Esta técnica surgió como resultado de un estudio conjunto de la Portland Cement Association (PCA) y la American Concrete Pavement Association (ACPA) para reducir al mínimo la cantidad de ruido en los pavimentos de hormigón. En la actualidad está técnica es ampliamente utilizada en calles urbanas y carreteras de todo EE.UU.
Eccentrically Loaded Small Scale Ring Footing on Resting on Cohesionless SoilIJERA Editor
A number of works have been carried out for the evaluation of a ultimate bearing capacity of shallow
foundation, supported by geogrid reinforced sand and subjected to centric load. Few experimental studies have
been made on the calculation of bearing capacity of shallow foundation on geogrid-reinforced sand under
eccentric loading. However these studies are for strip footings. This paper presents the behavior of ring footing
under eccentric loading on sand. The model tests have been conducted using ring footing with ring radii ratio
(Di/Do) = 0.4, 0.6, 0.8 for varring eccentricity ratio. Parametric studies have been made to find the impact of
eccentricity ratio, ring radii ratio and geogrid reinforcement on bearing capacity of the foundation.
The Geotechnical Properties of Jamshoro Soil (Shale) With CementIJMREMJournal
The geology of Jamshoro soil is nearly consist of multilayers in alternative form. The alternative layer of
Jamshoro soil occur in the form of lime stone and shale or vice versa. The basic aim of this research is to improve
the geotechnical properties of Jamshoro soil (shale) by using the cement as the stabilized material. This paper
reports the effect of cement on the geotechnical characteristic of the cohesive soil and swelling potential of the
Jamshoro soil. The soil sample used for testing purpose are thoroughly mixed to obtain the homogeneity. After
that thoroughly mixed was dried in the oven. Oven dried sample was mixed with cement at different proportion
that was 5% ,10%, 15% and 20% by the soil weight. Water content used in the mixture to form the specimens at
optimum moisture contents of the soil. The compacted this prepared soil specimen was done by followed the
procedure of standard proctor test. Compacted specimens were cured for the period of 1, 7, 14 and 28 days. After
the completion of curing duration of specimen direct shear test was done. On the base of experimental result, it
was concluded that the cement showed an appreciable improvement of the cohesion with the curing period.
EFFECT OF GROUTING ON STABILITY OF SLOPE AND UNSUPPORTED STEEP EXCAVATIONLakshmi Narayanan
Analysis of slopes for stability and safety is a major area of concern in civil engineering. To measure the effect of grouting on stability of slope, a scaled down prototype is created and cement grouting is applied by penetration method. The major finding of this project is a comparative study is based on application of grouting and the performance of the soil slope without grouting.
Objectives of the project
To determine the characteristics of soil and grouting materials.
To determine the physical properties and their applicability in different type of soil.
The main aim of the project is to find the effect of grouting on stability of slope.
The use of geo-grids in reinforced concrete sets a new dimension for employing
geo synthetics as reinforcement in structural concrete. The aim of the present study is
to investigate the use of geo-grid as a strengthening material to one way reinforced
concrete slabs. The experimental program contains testing of six RC slab
strengthened with different type of Geo-Grid and one reference slab. The specimens
have been tested under two line loads. Experimental results indicate that geo-grid
may be an effective alternative material for strengthening of reinforced concrete slabs
as compared to conventional confining techniques. Finally, A Finite Element model
(FEM) has been developed using ANSYS program to analyze the tested slabs, then the
experimental and theoretical results were compared.
Eccentrically Loaded Small Scale Ring Footing on Resting on Cohesionless SoilIJERA Editor
A number of works have been carried out for the evaluation of a ultimate bearing capacity of shallow
foundation, supported by geogrid reinforced sand and subjected to centric load. Few experimental studies have
been made on the calculation of bearing capacity of shallow foundation on geogrid-reinforced sand under
eccentric loading. However these studies are for strip footings. This paper presents the behavior of ring footing
under eccentric loading on sand. The model tests have been conducted using ring footing with ring radii ratio
(Di/Do) = 0.4, 0.6, 0.8 for varring eccentricity ratio. Parametric studies have been made to find the impact of
eccentricity ratio, ring radii ratio and geogrid reinforcement on bearing capacity of the foundation.
The Geotechnical Properties of Jamshoro Soil (Shale) With CementIJMREMJournal
The geology of Jamshoro soil is nearly consist of multilayers in alternative form. The alternative layer of
Jamshoro soil occur in the form of lime stone and shale or vice versa. The basic aim of this research is to improve
the geotechnical properties of Jamshoro soil (shale) by using the cement as the stabilized material. This paper
reports the effect of cement on the geotechnical characteristic of the cohesive soil and swelling potential of the
Jamshoro soil. The soil sample used for testing purpose are thoroughly mixed to obtain the homogeneity. After
that thoroughly mixed was dried in the oven. Oven dried sample was mixed with cement at different proportion
that was 5% ,10%, 15% and 20% by the soil weight. Water content used in the mixture to form the specimens at
optimum moisture contents of the soil. The compacted this prepared soil specimen was done by followed the
procedure of standard proctor test. Compacted specimens were cured for the period of 1, 7, 14 and 28 days. After
the completion of curing duration of specimen direct shear test was done. On the base of experimental result, it
was concluded that the cement showed an appreciable improvement of the cohesion with the curing period.
EFFECT OF GROUTING ON STABILITY OF SLOPE AND UNSUPPORTED STEEP EXCAVATIONLakshmi Narayanan
Analysis of slopes for stability and safety is a major area of concern in civil engineering. To measure the effect of grouting on stability of slope, a scaled down prototype is created and cement grouting is applied by penetration method. The major finding of this project is a comparative study is based on application of grouting and the performance of the soil slope without grouting.
Objectives of the project
To determine the characteristics of soil and grouting materials.
To determine the physical properties and their applicability in different type of soil.
The main aim of the project is to find the effect of grouting on stability of slope.
The use of geo-grids in reinforced concrete sets a new dimension for employing
geo synthetics as reinforcement in structural concrete. The aim of the present study is
to investigate the use of geo-grid as a strengthening material to one way reinforced
concrete slabs. The experimental program contains testing of six RC slab
strengthened with different type of Geo-Grid and one reference slab. The specimens
have been tested under two line loads. Experimental results indicate that geo-grid
may be an effective alternative material for strengthening of reinforced concrete slabs
as compared to conventional confining techniques. Finally, A Finite Element model
(FEM) has been developed using ANSYS program to analyze the tested slabs, then the
experimental and theoretical results were compared.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Experimental investigation was carried out to establish the feasibility of unprocessed stone
dust as fine aggregate in place of river sand which has become a scarcity now-a-days, by casting
cube and determining the compressive strength for the two grades of concrete M15 and M20. The
result obtained are compared with conventional concrete. It is concluded that compressive strength at
28 days of unprocessed stone dust used as fine aggregate in concrete gives 35% higher strength for
M15 and 4% for M20 grade concrete when compared to the reference concrete. The split tensile
strength of unprocessed stone dust concrete is 2.98 N/mm2
and 3.25 N/mm2
for M15 and M20 grade
respectively where as the reference concrete is 2.58 N/mm2
and 3.18 N/mm2
only. This investigation
has demonstrated that the unprocessed stone dust is equally good as fine aggregate like river sand
and hence can be used in making concrete
The following tests was performed by the students of Civil Engineering Department U.E.T Peshawar (the list of experiments can be seen in table of contents) under the supervision of Sir Engr. Zia Ullah..The main purpose of this lab was to investigate different types of soils through different tests and to compare them with the standards mostly ASTM.
A LABORATORY STUDY ON ACID MODIFIED BITUMINOUS MIXES IN COMPARISON FOR RUTTIN...civejjour
The rapid growth in trafficload intensity, tire pressure and traffic volume has put a hugedemand on pavements to perform satisfactorily for the design period. A number of efforts are made in the past to develop pavement materials that helped in attaining longer serviceability. Most of these efforts were directed towards improving the design of bituminous mix through modified bituminous binders. In this context an attempt is made to evaluate rutting characteristics of conventional bitumen modified with Poly phosphoric Acid (PPA). Immersion Type Wheel Rutting Machine was used for evaluation of rutting characteristics and is considered as one of the major critical criteria for design of pavement. Poly phosphoric Acid (PPA) is added as modifier to virgin bitumen (VG – 30) at regular interval of 1% up to 6% to the weight of Bitumen. Bituminous Concrete of Grade-II is considered for Analysis. Slabs of 400X300X50mm are prepared for evaluation of rutting characteristics. Stability, density, voids and flow parameters were determined using marshal test method for virgin and PPA modified mix. The result of immersion wheel rutting explains that acid modified binders resist more rutting compared to virgin binders. Acid modified mixes at 3% optimum performs better in rutting characteristics when tested in laboratory for induced applied pressures, load and number of passes.
A Laboratory Study on Acid Modified Bituminous Mixes in Comparison for Ruttin...civej
The rapid growth in trafficload intensity, tire pressure and traffic volume has put a hugedemand on
pavements to perform satisfactorily for the design period. A number of efforts are made in the past to
develop pavement materials that helped in attaining longer serviceability. Most of these efforts were
directed towards improving the design of bituminous mix through modified bituminous binders. In this
context an attempt is made to evaluate rutting characteristics of conventional bitumen modified with Poly
phosphoric Acid (PPA). Immersion Type Wheel Rutting Machine was used for evaluation of rutting
characteristics and is considered as one of the major critical criteria for design of pavement. Poly
phosphoric Acid (PPA) is added as modifier to virgin bitumen (VG – 30) at regular interval of 1% up to
6% to the weight of Bitumen. Bituminous Concrete of Grade-II is considered for Analysis. Slabs of
400X300X50mm are prepared for evaluation of rutting characteristics. Stability, density, voids and flow
parameters were determined using marshal test method for virgin and PPA modified mix. The result of
immersion wheel rutting explains that acid modified binders resist more rutting compared to virgin
binders. Acid modified mixes at 3% optimum performs better in rutting characteristics when tested in
laboratory for induced applied pressures, load and number of passes.
An experimental investigation was conducted to investigate the behavior of ultra-high strength reactive concrete (RPC) columns before and after strengthening with carbon fiber reinforced polymer (CFRP) sheets jacketing under eccentric axi al load. Twelve columns were tested up to failure, strengthened and retested to examine strengthening efficiency and to evaluate the effects of variation of the concrete type (normal or RPC), presence of steel fibers and main steel reinforcement ratio. Experimental results showed that CFRP jacketing increases the ultimate failure load of strengthened columns up to 185%, highly stiffens them (reduces lateral displacements) and allow more ductile failure than the original columns. Also, inclusion of steel fibers in RPC columns increases failure loads up to 86%, prevents palling of the concrete cover and increase the ductility.
An Investigation of the Interlayer Adhesion Strength in Deeper Layers of the ...AM Publications
A road pavement structure is typically composed of different layers arranged one on top of the other, all supported by a natural or improved subgrade. The main purpose of this configuration is to provide the most effective structure with adequate potential to spread traffic loading from the surface to the subgrade with minimum damage. In spite of material properties and construction techniques, researchers have shown that the overall pavement performance is significantly influenced by the interlayer adhesion condition throughout the pavement structure ([8], [11], [21], [22]). Lack of intimate contact between layers results in them acting as individuals rather than as a thick bonded unit. This therefore induces overloading of layers which leads to premature deterioration of the entire structure due to traffic induced distresses. This work, therefore investigated the interlayer adhesion characteristics between the granular base and the lightly cemented subbase of a typical South African pavement structure. The influence of bonding condition on the overall pavement performance was also studied. A series of interlayer direct shear tests was run on 300 x 300 mm samples made of two layers: a 100mm G2 Granular Base (GB) compacted on top of the 100mm Cement Treated Subbase (CTSB) composed of a G5 material stabilised with 1.8% of cement. Effects of the CTSB scarification, normal pressure and moisture conditions were analysed whereby the results of the interlayer strength tests were compared with those of intra-layer strength tests. The comparative analysis showed that scarifying the CTSB before laying the GB enhances intimate contact between two layers and stimulates the unison interaction which, according to structural modelling results, improves the overall pavement performance.
A comparative study between traditional method and mix design with industrial...Premier Publishers
Generally bituminous pavements face problems like cracks, rutting, depression and corrugation during it’s period of service. In this paper, we attempted various method of experiments both in traditional and mix design with bi products and therefore a comparative study has been made for extracting the finest results for the betterment of highway pavements (flexible) and for that our key elements were fly ash, geo-polymer and pieces of waste conveyer belt, added to bitumen for increasing the strength and overall capacity of pavements. Fly ash added to bitumen in the penetration test has shown improvement of 52 mm which was 40mm traditionally. Whereas, geo polymer and bitumen give the result of 74mm penetration. Ductility test with fly ash showed 37.23cm, very rigid. But geo-polymer and bitumen gave the result of 75.77cm. For increasing the bearing capacity of base soil we added pieces of waste conveyer belts and CBR value has shown the increment of 35% from 30%. So, those results convey that, the waste materials and bi products have enough quality to increase the strength and flexibility of pavements which will further help to the construction workers and engineers for maintaining and repairing flexible pavements which last long.
Fibre reinforced and ferrocement car park pavers by R Sri RavindrarajahSriravindrarajah Rasiah
Published at the Proceedings of the X International Symposium on Ferrocement and Thin Reinforced Cement Composites (FERRO 10),held in Havana, Cuba in Oct. 2012
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Experimental investigation was carried out to establish the feasibility of unprocessed stone
dust as fine aggregate in place of river sand which has become a scarcity now-a-days, by casting
cube and determining the compressive strength for the two grades of concrete M15 and M20. The
result obtained are compared with conventional concrete. It is concluded that compressive strength at
28 days of unprocessed stone dust used as fine aggregate in concrete gives 35% higher strength for
M15 and 4% for M20 grade concrete when compared to the reference concrete. The split tensile
strength of unprocessed stone dust concrete is 2.98 N/mm2
and 3.25 N/mm2
for M15 and M20 grade
respectively where as the reference concrete is 2.58 N/mm2
and 3.18 N/mm2
only. This investigation
has demonstrated that the unprocessed stone dust is equally good as fine aggregate like river sand
and hence can be used in making concrete
The following tests was performed by the students of Civil Engineering Department U.E.T Peshawar (the list of experiments can be seen in table of contents) under the supervision of Sir Engr. Zia Ullah..The main purpose of this lab was to investigate different types of soils through different tests and to compare them with the standards mostly ASTM.
A LABORATORY STUDY ON ACID MODIFIED BITUMINOUS MIXES IN COMPARISON FOR RUTTIN...civejjour
The rapid growth in trafficload intensity, tire pressure and traffic volume has put a hugedemand on pavements to perform satisfactorily for the design period. A number of efforts are made in the past to develop pavement materials that helped in attaining longer serviceability. Most of these efforts were directed towards improving the design of bituminous mix through modified bituminous binders. In this context an attempt is made to evaluate rutting characteristics of conventional bitumen modified with Poly phosphoric Acid (PPA). Immersion Type Wheel Rutting Machine was used for evaluation of rutting characteristics and is considered as one of the major critical criteria for design of pavement. Poly phosphoric Acid (PPA) is added as modifier to virgin bitumen (VG – 30) at regular interval of 1% up to 6% to the weight of Bitumen. Bituminous Concrete of Grade-II is considered for Analysis. Slabs of 400X300X50mm are prepared for evaluation of rutting characteristics. Stability, density, voids and flow parameters were determined using marshal test method for virgin and PPA modified mix. The result of immersion wheel rutting explains that acid modified binders resist more rutting compared to virgin binders. Acid modified mixes at 3% optimum performs better in rutting characteristics when tested in laboratory for induced applied pressures, load and number of passes.
A Laboratory Study on Acid Modified Bituminous Mixes in Comparison for Ruttin...civej
The rapid growth in trafficload intensity, tire pressure and traffic volume has put a hugedemand on
pavements to perform satisfactorily for the design period. A number of efforts are made in the past to
develop pavement materials that helped in attaining longer serviceability. Most of these efforts were
directed towards improving the design of bituminous mix through modified bituminous binders. In this
context an attempt is made to evaluate rutting characteristics of conventional bitumen modified with Poly
phosphoric Acid (PPA). Immersion Type Wheel Rutting Machine was used for evaluation of rutting
characteristics and is considered as one of the major critical criteria for design of pavement. Poly
phosphoric Acid (PPA) is added as modifier to virgin bitumen (VG – 30) at regular interval of 1% up to
6% to the weight of Bitumen. Bituminous Concrete of Grade-II is considered for Analysis. Slabs of
400X300X50mm are prepared for evaluation of rutting characteristics. Stability, density, voids and flow
parameters were determined using marshal test method for virgin and PPA modified mix. The result of
immersion wheel rutting explains that acid modified binders resist more rutting compared to virgin
binders. Acid modified mixes at 3% optimum performs better in rutting characteristics when tested in
laboratory for induced applied pressures, load and number of passes.
An experimental investigation was conducted to investigate the behavior of ultra-high strength reactive concrete (RPC) columns before and after strengthening with carbon fiber reinforced polymer (CFRP) sheets jacketing under eccentric axi al load. Twelve columns were tested up to failure, strengthened and retested to examine strengthening efficiency and to evaluate the effects of variation of the concrete type (normal or RPC), presence of steel fibers and main steel reinforcement ratio. Experimental results showed that CFRP jacketing increases the ultimate failure load of strengthened columns up to 185%, highly stiffens them (reduces lateral displacements) and allow more ductile failure than the original columns. Also, inclusion of steel fibers in RPC columns increases failure loads up to 86%, prevents palling of the concrete cover and increase the ductility.
An Investigation of the Interlayer Adhesion Strength in Deeper Layers of the ...AM Publications
A road pavement structure is typically composed of different layers arranged one on top of the other, all supported by a natural or improved subgrade. The main purpose of this configuration is to provide the most effective structure with adequate potential to spread traffic loading from the surface to the subgrade with minimum damage. In spite of material properties and construction techniques, researchers have shown that the overall pavement performance is significantly influenced by the interlayer adhesion condition throughout the pavement structure ([8], [11], [21], [22]). Lack of intimate contact between layers results in them acting as individuals rather than as a thick bonded unit. This therefore induces overloading of layers which leads to premature deterioration of the entire structure due to traffic induced distresses. This work, therefore investigated the interlayer adhesion characteristics between the granular base and the lightly cemented subbase of a typical South African pavement structure. The influence of bonding condition on the overall pavement performance was also studied. A series of interlayer direct shear tests was run on 300 x 300 mm samples made of two layers: a 100mm G2 Granular Base (GB) compacted on top of the 100mm Cement Treated Subbase (CTSB) composed of a G5 material stabilised with 1.8% of cement. Effects of the CTSB scarification, normal pressure and moisture conditions were analysed whereby the results of the interlayer strength tests were compared with those of intra-layer strength tests. The comparative analysis showed that scarifying the CTSB before laying the GB enhances intimate contact between two layers and stimulates the unison interaction which, according to structural modelling results, improves the overall pavement performance.
A comparative study between traditional method and mix design with industrial...Premier Publishers
Generally bituminous pavements face problems like cracks, rutting, depression and corrugation during it’s period of service. In this paper, we attempted various method of experiments both in traditional and mix design with bi products and therefore a comparative study has been made for extracting the finest results for the betterment of highway pavements (flexible) and for that our key elements were fly ash, geo-polymer and pieces of waste conveyer belt, added to bitumen for increasing the strength and overall capacity of pavements. Fly ash added to bitumen in the penetration test has shown improvement of 52 mm which was 40mm traditionally. Whereas, geo polymer and bitumen give the result of 74mm penetration. Ductility test with fly ash showed 37.23cm, very rigid. But geo-polymer and bitumen gave the result of 75.77cm. For increasing the bearing capacity of base soil we added pieces of waste conveyer belts and CBR value has shown the increment of 35% from 30%. So, those results convey that, the waste materials and bi products have enough quality to increase the strength and flexibility of pavements which will further help to the construction workers and engineers for maintaining and repairing flexible pavements which last long.
Fibre reinforced and ferrocement car park pavers by R Sri RavindrarajahSriravindrarajah Rasiah
Published at the Proceedings of the X International Symposium on Ferrocement and Thin Reinforced Cement Composites (FERRO 10),held in Havana, Cuba in Oct. 2012
Shear Behavior of Sand Reinforced with Plastic StripsEditorIJAERD
This research study presents the experimental work carried out to study the effect of plastic strips on shear
behavior of sand. Here, in this study sand has been used as base material and plastic strips as reinforcement material.
Small direct shear box applied as indicator test on sand in reinforced and plain/unreinforced conditions. Grain size
distribution tests and modified proctor tests were conducted on sand specimens in plain condition. In first attempt direct
shear tests were conducted under different normal stress conditions on representative specimens of sand in
plain/unreinforced conditions and various parameters of direct shear tests were considered. In second attempt sand
specimens were reinforced with random inclusions of plastic strips of different sizes and concentration of 0.1% and 0.2%
of the weight of dry soil specimen. Direct shear tests were repeated under different normal stress conditions as followed
in case of unreinforced conditions, and various parameters of direct shear tests were considered as followed in case of
plain/unreinforced sand specimens. Results of reinforced and unreinforced conditions specimens were matched. It was
observed that reinforced sand specimens yields better results than unreinforced sand specimens. An improvement in
angle of internal friction of sand was found as 16.67% with plastic strips dimensions of 6x15mm and at concentration of
0.2% of weight of sand specimen, so graphs of compression/dilation, shear stress and Mohr-Coulomb envelops of the
corresponding plastic strips dimension and concentration have been presented in this paper
Developing A Prediction Model for Tensile Elastic Modulus of Steel Fiber – Ce...IJRESJOURNAL
ABSTRACT: This paper attempts to develop a prediction model that can be used in line with prescribed laboratory experiments for indirect tensile test such that tensile elastic modulus can be predicted for cement stabilized lateritic soil reinforced with steel fiber using measured properties of the material. The results of the tensile elastic modulus obtained from the Derived Prediction Model almost nearly replicates that obtained from calculations from laboratory experimentation. Results obtained revealed that both the predicted values and calculated values have a linear correlation with an R2 of 96.4%. On this basis the Derived Prediction Model can be said to be valid within the limits of the study.
Modelling of Permanent Deformation on Flexible Pavement Using Accelerated Pav...IOSR Journals
Abstract: The two major distresses encountered on flexible pavement under Indian conditions are fracture
(cracking) and longitudinal permanent deformation (rutting) which affects the serviceability of pavement.
Accelerated Pavement Testing Facility (APTF) is a tool which is a vital link for testing and measuring full-scale
field behaviour of cracking and rutting of pavement at in-situ conditions. Recently, CSIR-Central Road
Research Institute (CRRI) in India has procured a linear Heavy Vehicle Simulator (HVS) type of APTF which is
presently being used for finding out the cracking and rutting behaviour of a flexible pavement consisting Dense
Bituminous Concrete (DBC) as wearing course and Dense Bituminous Macadam (DBM) as binder course apart
from the conventional granular layers above sub-grade.
The present paper deals with the development of a statistical model and its approach for pavement
rutting under numerous passes (bi-directional) for the layer specifications which are (i) 40 mm DBC (ii) 120
mm DBM (iii) 250 mm Wet Mix Macadam (WMM) and (iv) 300 mm Granular Sub-base (GSB) above the Subgrade,
which is an Indian Specification widely used for 30 Million Standard Axles (MSA) at 5% CBR. The
statistical model has been developed by observing / recording pavement surface profile using Laser
Profilometer (off board) for every 5,000 passes upto 50,000 passes, thereafter at every 10,000 passes upto
175,000 passes and then at every 25,000 passes upto 275,000 passes. The details of methodology adopted, load
applied, temperature and material properties have also been given in the paper.
Keywords: Flexible pavement, Rutting, Accelerated Pavement Testing Facility,Modelling,Profilometer
In the recent years, the rapid growths of population and industrialization levels have been
resulted in increased for demand of transportation. In addition, this growth increases the traffic loads
which cause several pavement distresses such as rutting. Several trials were made to control
pavement rutting by mix enhancement. These trials were already limited pavement rutting, but on the
other hand showed pavement cracking as a result of lower flexibility for the modified pavements.
This study aims at investigating the effect of crumb rubber on the characteristics of asphalt mixes. To
achieve this objective, crumb rubber with different percentages of fine aggregate (0, 4, 8, 12, 16, 20,
24 and 28%) were used to manufacture the investigated asphalt mixes. Marshall designs were used to
obtain the optimum asphalt contents and the corresponding characteristics of the investigated mixes.
Other mix characteristics including Marshall stiffness, loss of stability, tensile strength as well as
rutting resistance were measured for the investigated mixes. Loss of stability test, indirect tensile test
(ITT) and wheel tracking test (WTT) were conducted to measure these characteristics. Analyzing the
study results showed that, the use of crumb rubber has a noticeable effect on the characteristics of
asphalt mixes. It is noticed that, the use of rubber percent up to 16% by weight of fine aggregate
increases the pavement resistance to cracking and does not greatly affect the pavement resistance to
rutting.
EFFECT OF COMBINATION OF STEEL FIBRE AND CRUMB RUBBER ON THE PROPERTIES OF CO...AM Publications
This paper investigates the effect of combination of crumb rubber and steel fibre on the performance of concrete. Crum rubber ranging in size 20mesh was incorporated into normal concrete(NC) and steel fibre concrete with 0.75% volume fraction of hooked end steel fibres(SFC) mixes by partially replacing fine aggregate at four different ratios(5%,10%15% and 20%). The standard compressive strength test, splitting tensile strength test, and flexural strength test were conducted. Impact resistance test and abrasion resistance test were also applied on the mixes.
Experimental and Analytical Investigation of Drilling of Sandwich Composites:...IOSR Journals
A composite material is made out of a mixture or a combination of two or more distinctly differing
materials which are insoluble in each other and differ in form or chemical composition. The technological and
commercial interest in composite material lies in their superior properties of strength-to-weight, stiffness-toweight,
fatigue and thermal expansion compared to metals. Extensive use of composite in application such as
rockets, satellites, missiles, light combat aircraft, advanced light helicopter and trainer air craft has shown that
India is on par with the advanced countries in the development and use of composites in this area.
Drilling is probably the most important conventional mechanical process and it is the most widely used
machining operation. Prediction of cutting forces for any set of cutting parameters is essential in optimal design
and manufacturing of products. It has been predicted that most of the problem associated with hole making
operation, such as drilling, can be attributed to the force generated during cutting operation. Many
developments and experiments are going on drilling of Sandwich composite for damage free drilling along with
the quality of the hole and the effect of tool geometry and tool material.
This paper aims at the comprehensive analytical and experimental investigation work done on the
composites material. The conclusion of the paper discusses the development and outlines the trends for the
research in this field.
Rehabilitation of low volume flexible pavements by white topping a case studyeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
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Epav beneficios y ventajas cepillado de hormigon y ranurado de hormigonEPAV S.A.
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Indice de Condicion_de Pavimentos en Aeropuertos (PCI)EPAV S.A.
Esta metodología tiene el propósito de determinar la condición de pavimentos de aeropuertos a través de inspecciones visuales en superficies pavimentadas con asfaltos, incluyendo capas porosas de alto grado de fricción (Porous Friction Courses), y con hormigón, simple o reforzado, de cemento Pórtland con juntas, usando el Índice de Condición de Pavimentos (PCI) como método de cuantificación normalizado.
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Los estudios se programan de acuerdo con los objetivos de cada proyecto e incluyen, entre otros, medición de fricción, acumulación de agua en pista y condiciones de seguridad.
EPAV - Soluciones de Calzada por Nivel de ServicioEPAV S.A.
CONSERVACION PERIODICA
Las operaciones de Conservación Periódica se aplican al pavimento para efectuar ajustes o pequeños arreglos que generalmente es necesario realizar en forma cíclica, a distintos intervalos. Todo esto para corregir posibles fallas o prevenir daños mayores, producidos normalmente por efecto del clima, la composición del tránsito y el tiempo de servicio. Este servicio es un acuerdo de trabajo constante en el tiempo y busca así prevenir cualquier daño mayor y evitar mayores gastos cuando la superficie del pavimento está ya completamente damnificada.
CONSERVACION RUTINARIA
Las operaciones de Conservación Rutinaria tienen por objeto la conservación, limpieza y buen funcionamiento de la obra física y se llevan a cabo normalmente a intervalos regulares predeterminados. A diferencia de la Conservación Periódica, ésta es programada por fechas estipuladas.
CONTRATOS POR NIVELES DE SERVICIO
Los contratos por niveles de servicio, por estándares, o por resultados son una innovadora forma de llevar a cabo la conservación vial, en la cual empresas privadas pueden hacer un aporte singular a una conservación vial más efectiva. Bajo este tipo de contrato, es necesario conservar las vías siempre igual o mejor que las características que se hayan fijado, lo que ayuda a que efectivamente se logre mantenerlas en buen estado y a costos de largo plazo inferiores a los tradicionales.
La introducción de esta modalidad de contrato se enmarca dentro de una tendencia creciente en los organismos viales de considerar a los usuarios como clientes, a quienes debe ofrecerse el servicio de redes viales en buen estado. En la medida que esta tendencia se consolide, es dable esperar que las necesidades de los usuarios serán satisfechas de una mejor manera y se dispondrá de vías más seguras, confortables y económicas.
La recolección, encauzamiento y disposición de las aguas pluviales -tanto superficiales como subterráneas- son una tarea esencial para garantizar la estabilidad e integridad de una vía urbana e interurbana. A la par de sus otros servicios en
pavimentación, EPAV ofrece un servicio de Sistema de Drenaje vial para asistir la retirada de las aguas que se acumulan
en depresiones topográficas del terreno.
Lo anterior con el fin de dar durabilidad a la carpeta de rodado existente y asegurar el seguro tránsito de los vehículos, ayudando de paso a evitar el hidroplaneo y mejorar la adherencia de los neumáticos.
EPAV ofrece la aplicación de Sellos Asfalticos para aquellos casos en que se requiera impermeabilizar y mejorar la
adherencia de los vehículos a un determinado camino.
Estos sellos -hechos a base de delgadas soluciones de asfalto-, sirven también para reparar las vías dañadas por el clima, el uso indebido de vehículos pesados o el tiempo. Además, tienen la gran ventaja de que son rápidos de aplicar y se pueden utilizar a las pocas horas de haberse fijado.
EPAV - Sello de Juntas y Grietas en PavimentosEPAV S.A.
Las fallas por agrietamiento de los pavimentos son causadas principalmente por procesos de contracción y esfuerzos mecánicos de sobrecarga; a éstos se le suma el envejecimiento y oxidación generados por condiciones climáticas como lluvia, viento y sol.
Todo lo anterior hace que el agua penetre por estas fallas provocando un reblandecimiento de la base y, en el peor de los casos, el socavamiento bajo la carpeta de rodado por arrastre de finos, lo que resulta en el deterioro prematuro del pavimento.
El resello de juntas y sellos de grietas en pavimentos en un programa de mantenimiento que reduce el deterioro y ayuda a conservar el estado de este. La vida útil de un pavimento puede prolongarse al menos en 2 años realizando el sellado en el momento adecuado, permitiendo mantener la serviciabilidad del pavimento.
La circulación vehicular debe ser guiada y regulada a fin de que ésta pueda llevarse a cabo de forma segura, fluida, ordenada y cómoda. En ese sentido, la Seguridad Vial con su respectiva demarcación y señalética de tránsito es un elemento fundamental para alcanzar tales objetivos y evitar riesgos.
En el caso del trabajo en ruta y de manera de orientar el desplazamiento, evitar accidentes y asegurar la integridad de conductores, peatones, ciclistas o motoristas, EPAV puede realizar diferentes tipos de trabajos.
Las tareas de Reperfilado de la Superficie que realiza EPAV implican los trabajos necesarios para
reconformar la plataforma de los caminos de grava o tierra, incluyendo las cunetas.
Todo esto para conseguir una condición lo más parecida a la primitiva de diseño o a un diseño mínimo.
Se definen todas las labores que se requieren para que, actuando sobre el material existente, se logren
las mejores condiciones posibles de transitabilidad y geometría.
EPAV - Remocion del Caucho en Pistas de AeropuertosEPAV S.A.
El método consiste en el retiro en forma suave de todo el caucho, mediante el paso de un set de discos diamantados sobre la superficie y/o ranura en forma transversal a la pista, en una profundidad mayor o igual al espesor del caucho acumulado.
No es un método que induzca tensiones o que altere la estructura de la carpeta de rodado.
El pavimento recupera su condición de fricción inicial e incluso casos la mejora. Solo retira el caucho acumulado de la superficie por lo tanto se puede realizar tantas veces como se requiera.
Mediciones preliminares de fricción dan valores cercanos a 0,70.
EPAV - Recuperacion de Friccion Pavimentos AeropuertosEPAV S.A.
El texturado es una técnica innovadora, desarrollada en Chile que permite recuperar el coeficiente de rozamiento de la superficie de pistas de aterrizaje en pavimentos de hormigón.
Esta técnica es aplicada en forma transversal a la pista con lo cual el aeropuerto no pierde su operatividad durante la ejecución de sus trabajos.
La Recarga de Grava es una alternativa de servicio que ofrece EPAV en casos en que se requiera colocar una capa de grava sobre una carretera no revestida y así reemplazar la que se ha perdido por la acción del tránsito y del agua lluvia. De la misma el Recebo es una opción de tratamiento de relleno con grava fina, arena o suelo en la construcción del pavimento.
El Recapamiento Asfáltico es un recurso ampliamente utilizado en la recuperación de pavimento y presenta un desafío recurrente: "evitar el surgimiento de grietas reflectadas". Estas grietas no son más que una imagen reflejada de las fisuras o juntas de dilatación que el pavimento pretende recuperar y su surgimiento indica inequívocamente un proceso de destrucción del recapado.
La tendencia predominante de los principales países europeos y americanos ha sido la utilización de una geogrilla de refuerzo de alto módulo de elasticidad. La función principal es absorber las tensiones provenientes de las dilataciones o deformaciones de las placas de pavimento antiguo, provocadas por el tráfico de vehículos o dilatación y contracción térmica de los elementos del pavimento antiguo.
El refuerzo de fibra de vidrio absorbe así las capacidades que, de otro modo, estarían actuando sobre la capa de rodado aumentando su capacidad de deformación elástica. Este fenómeno reduce la falla del material por fatiga y es particularmente eficaz en ambiente de altas temperaturas, donde normalmente disminuyen las propiedades mecánicas del asfalto.
EPAV - Ranurado Transversal en AeropuertosEPAV S.A.
El despegue y aterrizaje de las aeronaves requiere en todo momento una buena interacción y contacto entre sus ruedas y la superficie del pavimento.
El ranurado transversal consiste en el acanalado del pavimento en forma perpendicular a la pista, de esta manera se generan ranuras que la cruzan en forma ininterrumpida.
Esta técnica se puede utilizar tanto en superficies de hormigón y como de asfalto.
El servicio de Pavimentos Delgados de hormigón aplicado por EPAV es una excelente alternativa para aquellos casos en se pretenda optimizar el uso del hormigón en un pavimento y dar una competitiva alternativa a la opción de aplicar asfalto.
Técnicamente este servicio implica la reducción de los espesores del hormigón, a través de la reducción de la longitud y ancho de las losas que componen el pavimento. Sin embargo lo anterior, tiene las mismas virtudes que un pavimento tradicional de concreto
EPAV - Pavimentacion Asfaltica y en HormigonEPAV S.A.
EPAV ofrece servicios de pavimentación de calles, carreteras, caminos rurales y pistas de aeropuertos. Al ser especialistas en la rehabilitacion de pavimentos, en las faenas de pavimentación conocemos todo tipo de material o técnica. Además, nuestro equipo puede dar asesoría sobre el mejor uso de materiales.
El Estabilizado de Losas de Hormigón consiste en el bombeo de una lechada de cemento para rellenar los vacíos, justo por debajo de las losas, con el fin de estabilizar el pavimento.
Normalmente la formación de vacíos se produce debido al bombeo producido por las cargas de tránsito pesado y la consolidación de la subrasante debido a altas deflexiones de esquina.
El Estabilizado de Caminos es una técnica que puede aplicar EPAV para aquellas rutas en que se necesite evitar el levantamiento de polvo
Para ello se puede aplicar una solución con sal y/o bischofita disuelta en agua en la capa de rodadura granular, que al combinarse con el material fino de la capa de rodadura se cohesiona, formando así una superficie que impide la liberación de polvo y brinda una mayor estabilidad y durabilidad a la capa de rodadura.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
Every time when lecturers/professors need to conduct examinations they have to sit down think about the questions and then create a whole new set of questions for each and every exam. In some cases the professor may want to give an open book online exam that is the student can take the exam any time anywhere, but the student might have to answer the questions in a limited time period. The professor may want to change the sequence of questions for every student. The problem that a student has is whenever a date for the exam is declared the student has to take it and there is no way he can take it at some other time. This project will create an interface for the examiner to create and store questions in a repository. It will also create an interface for the student to take examinations at his convenience and the questions and/or exams may be timed. Thereby creating an application which can be used by examiners and examinee’s simultaneously.
Examination System is very useful for Teachers/Professors. As in the teaching profession, you are responsible for writing question papers. In the conventional method, you write the question paper on paper, keep question papers separate from answers and all this information you have to keep in a locker to avoid unauthorized access. Using the Examination System you can create a question paper and everything will be written to a single exam file in encrypted format. You can set the General and Administrator password to avoid unauthorized access to your question paper. Every time you start the examination, the program shuffles all the questions and selects them randomly from the database, which reduces the chances of memorizing the questions.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
EPAV - Nueva Generacion de Bajo Mantenimiento de Pavimentos de Hormigon (ingles)
1. Development of the Next Generation Low
Maintenance Concrete Surface
Larry Scofield, P.E.
American Concrete Pavement Association
Paper prepared for presentation at the National Conference on
Preservation, Repair and Rehabilitation of Concrete Pavements,
St. Louis, Missouri, April 2009
January 2009
Development of the Next Generation Low Maintenance Concrete Surface
2. 1
Abstract
In 2005, the Portland Cement Association (PCA), through the American Concrete
Pavement Association (ACPA), funded research to improve the noise performance of
concrete pavements. The International Grooving and Grinding Association (IGGA),
through its affiliated contractors supported the research effort through equipment
development and test section construction.
The research was undertaken by Purdue University’s Herrick Laboratories using
their Tire Pavement Test Apparatus (e.g. TPTA). The TPTA is capable of testing any
pavement texture that can be produced. This allows evaluation of texture designs which
are not constrained by current construction capabilities or costs associated with field test
section construction and evaluation. More importantly, the TPTA allows evaluation of
textures without the resulting traffic control or safety issues.
Purdue’s concrete pavement research was targeted on both new construction and
pavement rehabilitation. Purdue’s preliminary efforts focused on evaluation of the
variables affecting tire-pavement noise generation characteristics of diamond ground
surfaces. This paper reports on the development and findings of that work.
The Purdue work evaluated the variables affecting construction of diamond
ground textures and the joint slab effect associated with transverse joint noise generation.
The findings of the Purdue work indicated that the geometric configuration of the blades
and spacers used to construct diamond ground textures was not the controlling factor in
noise generation; but rather the resulting fin profile was the most important factor. To
produce a low noise diamond ground surface required producing uniform and consistent
fin profiles.
To verify this finding, a new surface was produced that consisted of a very
uniform fin profile design with essentially only negative texture. This surface texture
produced the lowest tire-pavement noise levels produced in the research. The surface
was then constructed in the field using actual diamond grinding equipment to confirm the
laboratory based study. A new surface, now called the Next Generation Concrete Surface
(e.g. NGCS) was essentially implemented and is being constructed in test sections to
evaluate its long term performance.
NGCS is a term used to describe a category of texture(s) that have or will evolve
through current research. The term may apply to several textures that evolve for both
new construction and rehabilitation of existing surfaces. The desirable characteristics of
such textures will be a very smooth profile coupled with good micro texture and excellent
macro texture.
To date, three field trials have been constructed and one competitively bid
construction project. Friction testing and On-Board Sound Intensity (OBSI) levels have
been obtained at two of the sites and are reported herein.
3. 2
I Introduction
Recognizing the national interest in quiet pavements, in 2004 the PCA and ACPA
developed a program to research the surface characteristics of concrete pavements. This
program, funded by the PCA and administered by the ACPA, was designed as a three
year program which began in 2005. The IGGA and several of its members also provided
financial and creative support for the program. The program had three main objectives;
(1) evaluation and development of a quieter diamond ground surface, (2) evaluation and
development of new construction surfaces, and (3) evaluation of the joint slap effect.
Only the development of a quieter concrete diamond ground surface is discussed in this
paper.
II Purdue Tire Pavement Test Apparatus
Purdue University’s Herrick Laboratory conducted the research using their Tire
Pavement Test Apparatus (e.g. TPTA). The TPTA, shown in the right-hand side of
Figure 1, consists of a 38,000-pound, 12-foot-diameter drum that makes it possible to test
numerous types of pavement textures and compositions in combination with various tire
designs. Six, curved test-pavement sections fit together to form a circle. Two tires,
mounted on opposite ends of a beam, are then rolled over the test samples at varying
speeds while microphones and other sensors record data. As indicated in Figure 1, two
wheel tracks were constructed on each of the six curved test panels allowing 12 surface
textures to be tested in one setup. Speeds between 0- 30 MPH can be tested and test
temperatures ranging between 60-80 degrees are possible.
1 TPTA Equipment
Figure 1 Purdue Tire Pavement Test Apparatus and IGGA Diamond Grinding
Head
The left hand side of Figure 1 indicates the diamond grinding head that was
constructed by Diamond Surfaces, Inc of the IGGA. This head was used to grind all the
surfaces studied. It constructs an 8 inch wide diamond ground surface. Typical diamond
grinding units grind 3 ft and 4 ft wide paths and use 50-60 blades per foot. To fully
“stack” a head, it can cost $50K and take 6-8 hrs of stacking time. The use of a small, 8
TPTA
IGGA Diamond
Grinding Head
4. 3
inch-wide head, tremendously reduces the blade cost and set-up time. When comparing
different grinding blade/spacer configurations, this is a very important consideration.
The grinding unit replaces one of the wheel set ups as indicated in Figure 1. Once the
surfaces are diamond ground, the unit is removed, the test wheel apparatus re-installed,
and testing is conducted.
The Purdue TPTA was the innovative workhorse for the PCA/ACPA/IGGA
surface texture efforts. This device allows textures to be produced and tested that may
not currently be possible to construct with present day equipment. Additionally, testing
can be accomplished without requiring traffic control or endangering workers or
travelers.
2 TPTA Measurement Systems
Figure 2 indicates the OBSI equipment used to measure tire-pavement noise and
the RoLine laser used to measure texture profiles. As indicated in the left-hand side of
Figure 2, the OBSI equipment was mounted to the test tire support frame. Since two tires
are used during testing, it was possible to test with two different tire types at the same
time.
The right-hand side of Figure 2 indicates the texture measurement system.
Texture measurement was accomplished by removing one of the tire support frames and
installing an arm to support the RoLine sensor.
Figure 2 OBSI and RoLine Test Equipment Mounted to TPTA
3 Purdue Test Plan
The Purdue diamond grinding research was predicated upon varying the blade
width and spacer width to develop the optimum grinding configuration. It was
recognized that only one concrete mixture was to be used for all specimen preparation
and that this would limit the optimization to the given mix and aggregate type. However,
the belief was that any findings would be useful in understanding other mixes as well and
that additional research could be pursued if necessary. Historically, the industry
constructed field test sections for research purposes, and this almost always consisted of
varying the spacer and blade types. As such the industry requested that Purdue approach
their research by varying the blade and spacer widths and configurations.
5. 4
After evaluating the range of blade and spacer widths requested by the industry,
Purdue advised that no unique relationship could be found between spacer width, blade
width, and spacer/blade configuration. Instead, it appeared that the controlling variable
was the variability in the fin profile height resulting from the grinding process.
Figure 3 indicates a close up photo of the fin profile just after grinding and before
any fins are knocked down due to traffic and winter maintenance operations. As evident
in the photo, the harder aggregate stand “proud” in relationship to adjacent areas. Purdue
indicated that it was probably this variability in fin profile that affected the tire-pavement
noise generation. Textures with low variability were quieter than textures with high
variability. In conventional diamond grinding, the resulting fin variability is influenced
by the blade/spacer configuration, the concrete mixture, aggregate type, pavement
condition, equipment set up, etc. This makes it very difficult to control from an
experimental standpoint.
Figure 3 Variability of Fin Profile on Conventional Diamond Ground Surface on
MnROAD I-94
To evaluate this hypothesis, it was decided to produce a texture with essentially
no positive texture. That is, the surface would be diamond ground smooth and then
additional texture imparted by grooving. In this manner, the exact fin profile could be
controlled/anticipated at the time of production, unlike conventional diamond ground
(CDG) surfaces which are affected by many variables. Figure 4 indicates one of these
surfaces. It should be noted the that the CDG surface shown in Figure 3 produces texture
in the upward or positive direction while the Purdue surface produces texture in the
downward or negative direction. The Purdue texture, later called the Next Generation
Concrete Surface (NGCS) was desirable from the standpoint that it was more of a
“manufactured surface” and thus could be controlled as necessary from an experimental
basis.
When these new textures (NGCS) were tested on the TPTA they produced the
quietest of all surfaces tested to date. This was an epiphany in the research as it verified,
for the first time, what the controlling factor was for tire-pavement noise generation of
diamond ground surfaces.
Fin
6. 5
Figure 4 Photo of Purdue Negative Texture Profile (e.g. NGCS) and Land Area
III Test Section Construction
1 Proof of Concept Field Testing
The epiphany was soon confronted by reality. The Purdue grinding consisted of
grinding an 8 inch wide wheelpath for 6 ft for each of the specimens. When grinding
such small areas the heat generated by the head is not excessive. However, when
diamond grinding a pavement with a conventional machine, with a 3 ft or 4 ft head, this
is not the case. The typical 1/8 inch opening provided by a spacer between the grinding
blades allows water to circulate between them, cooling them and removing grinding
debris. This is an important consideration in production grinding. In addition, flush
grinding the surface prior to grooving requires approximately twice as many blades. For
an 8 inch head such as Purdue’s, this is not prohibitively expensive. To do it with a 3 or
4 ft grinding head could cost upwards of $60,000; quite a risk/investment for an unproven
strategy. The Purdue research indicated that the flush grind/grooved texture could
produce a quieter texture, but it could not verify whether it could be constructed with
conventional equipment in the field.
Prior to attempting field validation, two grinding/grooving configurations were
developed and tested in the laboratory at Purdue. The first was a grinding configuration
that used three smaller diameter blades stacked between two taller blades and the pattern
repeated across the grinding head. The taller blades were approximately 2 mm larger.
This arrangement provided a single pass operation that could grind the surface smooth
and also groove it on approximate ½ inch centers in one pass of the machine. The
smaller blades were used to flush grind the roadway and provide micro texture while the
taller blades were used to create grooves. The Purdue work had also demonstrated the
advantage of micro texture in reducing noise levels.
The second grinding configuration used the same smaller blades to “flush” grind
the pavement in the first pass over the surface. A second pass was then made using the
same taller blades with spacers between them to create the approximate ½ inch on center
Land Area
7. 6
spacing. This second pass provided grooves similar to what was constructed with the
single pass configuration.
The purpose for the two different configurations, designed to achieve the same
end result, was to allow consideration of either option by contractors. Some industry
representatives did not consider the single pass operation as a viable option in a
production environment due to excessive blade wear and the potential for ruining the
head/blades. Many believed the two stage process would be required. So both options
were pursued. Both surfaces produced similar results on the TPTA so field trials were
pursued.
The opportunity to construct field test sections became a reality when the
Minnesota DOT allowed construction of the test sections indicated in Figure 5 at the
MnROADS Low Volume Road Test Cell Number 37. At approximately this same
location, Diamond Surfaces, Inc. had equipment uniquely designed to construct the
proposed sections. The equipment consisted of a diamond grinding unit with a 2 ft head
designed for curb cuts. This device not only allowed for fewer blades to be used but also
was designed to allow quick blade changes. A head of blades could be changed in
approximately 45 - 60 minutes versus 6 – 8 hrs.
The test strips indicated in Figure 5 represented a compromise between the ability
to conduct OBSI testing at 60 mph and requiring as few blades to construct a test strip. It
was estimated that an 18 inch wheel track was the narrowest that that could be tested at
60 mph and still ensure the test wheel was within the test strip.
Additionally, the two Purdue surfaces were to be compared to a conventional
diamond grinding surface (e.g. CDG) to assist in determining the benefit achieved by
controlling fin profile. This resulted in the need to construct three diamond ground
surfaces.
Figure 5 Proof of Concept Field Test Strips at MnROADs Low Volume
Roads Test Area
Single Pass-Grind & Groove
Two Passes; Flush Grind First pass, Groove Second Pass
Conventional Diamond Grinding
Existing Random Transverse Tining
8. 7
The purpose of the test section construction was twofold: First, to verify the
hypothesis that controlling the texture (e.g. fin) profile in contact with the tire could result
in lower noise surfaces; and secondly, to verify that the results obtained using the TPTA
could be reproduced in the field on real pavements using actual construction procedures.
The standard diamond grinding wheel track (e.g. TS3 in Figure 5) was
constructed with the blades and spacers existing on the equipment to eliminate the need
to restack the head one more time. This resulted in TS3 being constructed 24 inches wide
while TS1 and TS2 were constructed 18 inches in width to reduce the number of blades.
The test sections were constructed upon a 14 year old PCCP that had originally been
textured with random transverse tinning.
Wheel tracks TS2 and TS1 were constructed with new “flush” grind blades which
had been dressed to ensure they were essentially the same diameter so that a flat surface
with micro texture could be produced. Taller new blades were also used which were
approximately 2 mm larger in radius than the “flush” grind blades. TS 2 was constructed
in two operations and TS1 in a single operation. The diamond grinding unit constructed
each wheel track in approximately 40 to 50 minutes. Equipment travel speed was on the
order of 10-12 feet per minute. Both the single pass and double pass procedures were
successfully constructed in June of 2007.
The findings, as discussed later, validated both that the Purdue Texture was
quieter, at the time of construction, than the conventional diamond grind texture and that
the Purdue TPTA results could be reproduced in the field using conventional equipment.
With the validation of the TPTA results, the next step was to construct a full-width test
section using a conventional diamond grinding machine. This would allow trafficking of
the test section as well as additional insight into the production side of the Purdue texture
(NGCS).
2 Mainline Construction
The first opportunity to construct a full lane-width test section occurred on the
Chicago Tollway on I-355. At this site, both a conventional diamond ground (CDG) test
section and a Purdue texture (eg NGCS) were successfully constructed in October of
2007. The sections were 1200 ft long and one lane-wide. This section of freeway was a
newly constructed alignment which had not been open to traffic prior to constructing the
test sections. The two pass process was used to construct the Purdue texture (e.g. NGCS)
The next opportunity to construct test sections occurred at MnROAD’s on the I-
94 section. A two-lane wide by 500 ft long section of Purdue texture (e.g. NGCS) was
constructed in a single pass on a 14 year old random transverse tined pavement in
October of 2007 on a new roadway. With the successful placement and performance of
the two mainline sections, the ACPA officially named the Purdue textures as the “Next
Generation Concrete Surface” (NGCS). This naming occurred to describe a category of
texture(s) that have or will evolve through current research. The term may apply to
several textures that evolve for both new construction and rehabilitation of existing
9. 8
surfaces. The desirable characteristics of such textures will be a very flat profile coupled
with good micro texture and excellent macro texture.
Two additional NGCS sections were constructed in the fall of 2008, one in
Wisconsin and one in Kansas. The Kansas NGCS was constructed as part of the Kansas
two lift PCCP test project. Other Kansas textures evaluated consisted of drag textures,
exposed aggregate, longitudinally tined, and a conventional diamond ground section.
The Wisconsin project is unique in that it was the only project in which the NGCS
section was bid as a normal construction project and not as a change order or section
constructed by the industry. The Wisconsin section was constructed too late in the year
to obtain meaningful test results. Additionally, the section was constructed through a
town that had a posted speed limit of 25 mph in the vicinity of the CDG section and 35
mph in the vicinity of the NGCS section. OBSI testing is typically conducted at 60 MPH.
All the NGCS sections were successfully constructed and were the quietest
textures placed. The OBSI and friction characteristics are discussed in subsequent
sections. The NGCS is still in the evaluation phase and ways of making the surface more
cost effective are being considered. Currently, this surface is considerably more
expensive than CDG surfaces.
IV On-Board Sound Intensity (OBSI) Measurements
The ACPA has conducted OBSI testing on the test sections to evaluate their long
term performance. The testing is conducted at 60 mph using a dual vertical-probe OBSI
system mounted to a Chevy Malibu with an ASTM SRTT test tire. This testing is used to
represent the tire-pavement noise generation of the respective surfaces.
1 Pre-Opening to Traffic
i Pre-Traffic OBSI Conclusions
The pre-traffic OBSI results for the MnROADs and Illinois test sections are
indicated in Figures 6 & 7. The proof of concept test section results conducted on the
MnROADs low volume road test sections are also presented. There are a number of
things to note in these figures: (1) the NGCS results were always lower than the CDG
results; (2) the NGCS results are consistent while the CDG are variable; (3) the NGCS
has a somewhat different spectral plot than the CDG as indicated in Figure 7. Testing
indicated that the NGCS surface is quieter below 1000 Hz and between 1000 Hz and
1600 Hz. Above 2000 Hz it is nosier. There is a significant drop in the spectrum at the
1600 Hz center band frequency for the NGCS surface.
It should be noted that no adjustments for the effect of temperature on OBSI
levels have been made.
10. 9
Figure 6 ACPA OBSI Results for MN I-94 & IL I-355 Sections
Figure 7 One Third Octave Spectral Plots for MN I-94 & IL I-355 Sections
104.3
100.1 100.2
99.6 99.4
99.1
102.0
94
96
98
100
102
104
106
108
110
SoundIntensityLevel,dBA
Pavement Section
I-94 WB
CDG
125B-
120S
I-94 WB
NGCS
SP
I-355 NB
CDG
125B-105S
I-355
NB
NGCS
DP
MnROAD
LV Road
NGCS
SP
MnROAD
LV Road
NGCS
DP
MnROAD
LV Road
CDC
125B-120S
75
80
85
90
95
100
105
500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
SoundIntensityLevel,dBA
1/3 Octave Band Center Frequency, Hz
MnROAD I-94 WB CDG
NGCS I-94 WB SP
NGCS Chicago I-355 NB
DP
Chicago I-355 NB CDG
NGCS MnROAD LV SP
NGCS MnROAD LV DP
MNROAD LV CDG
11. 10
ii Comparison to Other Textures on I-355 on 11-4-07
OBSI testing of the diamond ground surfaces was conducted on I-355 just prior to
opening and the results compared to other textures on this same segment of roadway.
The results are indicated in Figure 8 & 9. Figure 8 indicates the overall levels while
Figure 9 indicates the frequency spectrums. OBSI testing was conducted on all sections
at the same time and temperature.
Figure 8 Chicago I-355 OBSI Overall Level Results from 11-4-07
Figure 8 indicates that the NGCS surface was almost 5 dBA quieter than the
random transverse tined surface. Figure 8 also indicates that the CDG and NGCS are
similar in noise level. The longitudinal grooved drag texture was almost 2 dBA higher
than the NGCS suggesting that the grooves alone were not the solution.
2 Post Opening to Traffic Test Results
Both the I-94 and I-355 test sections are located in areas with harsh winters and
experience snow plow operations. Test results reported in this section represent
performance after one winter of snow and ice control and interstate level traffic. I-94 in
Minnesota has high percentages of truck traffic while I-355 has relatively low ADT and
truck traffic.
Figure 10 indicates the OBSI levels for each of the two field test locations that are
under traffic conditions. Both sites had received approximately five months of traffic at
the time of testing. The conventional diamond grinding (e.g. CDG) is indicated in light
100.5 100.7
103.1
102.0
105.2
94
96
98
100
102
104
106
108
110
SoundIntensityLevel,dBA
Pavement Section
Next
Generation
Concrete
Surface
(NGSC)
Conventional
Diamond
Grinding
1/2 "
Uniform
Transvers
e Tined 3/4"
Longitudina
l Grooved
Random
Transverse
Tined
12. 11
green and the NGCS sections indicated in dark green. For each location and surface type,
the oldest test result is displayed to the left of the most current result. The I-94 sections
are indicated in the left half of the figure and the I-355 sections in the right half. The
results shown are the average of three tests for each surface type. Figure 11 indicates the
spectral results for both locations.
Figure 9 Chicago I-355 OBSI Spectrum Results of Selected Textures Tested
11-4-07
104.3
100.7
100.1
99.0
100.7 100.9
100.5
100.9
94
96
98
100
102
104
106
108
110
SoundIntensityLevel,dBA
Pavement Section
Minnesota I‐94 Chicago I‐355
Conventional
Diamond
Grinding Next
Generation
Concrete
Surface
10‐25‐07
5‐12‐08
10‐25‐07
5‐12‐08
Conventional
Diamond
Grinding
Next
Generation
Concrete
Surface
11‐4‐07 5‐12‐08 11‐4‐07 5‐12‐08
Figure 10 Comparison of CDG to NGCS OBSI Levels Through 5-15-08
75
80
85
90
95
100
105
500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
1/3 Octave Band Center Frequency, Hz
SoundIntensityLevel,dBA
Next Generation Concrete
Surface (NGCS)
Conventional Diamond Grinding
(CDG)
Longitudinal Groove
1/2" Uniform Trans Tine (UTT)
Random Transverse Tine (RTT)
13. 12
When reviewing Figure 10 and 11, there are a number of things to note: (1) As
evident in Figure 11, the NGCS frequency pattern is slightly different than the CDG. The
NGCS has a characteristic dip at 1600 Hz and is typically lower in level at all frequencies
below this dip and higher in level at all frequencies above the dip. This is consisted with
the pre-traffic results. The NGCS produces a more broadband noise and may be less
objectionable. (2) The overall level of the CDG and NGCS are more similar in the
trafficked condition than in the as-constructed condition. This is a result of the wearing
down of the CDG fins (see Figure 12 and contrast this with Figure 3). (3) The NGCS has
produced more consistent results. That is, they are essentially at their final noise level at
the time of construction and do not have to wear away to a “finished level”.
Figure 11 1/3 Octave Spectra Plots for I-94 and I-355 CDG and NGCS Test
Sections
As indicated in Figure 10, the CDG and NGCS sections were only 0.2 dBA
different in level at the November 2007 testing with the NGCS being quieter. During the
May 2008 testing both surfaces produced similar results. The NGCS tested
approximately 0.4 dBA louder in May than the November measurements, while the CDG
tested 0.2 dBA louder. These differences are probably within the test repeatability of the
OBSI equipment. In addition, this site location exhibits a slight joint slap. To date, the
impact of the joint slap or diurnal change on test readings is undetermined.
75
80
85
90
95
100
105
500 630 800 1000 1250 1600 2000 2500 3150 4000 5000
SoundIntensityLevel,dBA
1/3 Octave Band Center Frequency, Hz
I-94 CDG 5-15-08
I-94 NGCS 5-15-08
I-94 CDG 10-25-07
I-94 NGCS 10-25-
07
I-355 NGCS 5-12-
08
I-355 NGCS 11-4-
07
14. 13
Figure 12 MnROAD I-94 Conventional Diamond Ground Texture After Five
Months of Traffic
It should be noted that the I-355 sections used ¾” center to center groove spacing
instead of the ½” center to center spacing developed at Purdue. This was to
accommodate the use of the same grooving equipment that was used to construct the
longitudinally grooved turf drag.
V Friction Performance Testing
The friction performance of the MnROADs I-94 test section has been monitored
by MnROADs since the construction of the test sections. Figure 13 indicates the time
series behavior of the sections for both the ASTM ribbed (E501) and smooth (E524) tires.
It should be noted that I-94 was closed to traffic on 4/2/08 to allow construction of new
test sections on the facility. So there is approximately five months of interstate traffic on
the test sections. The “traffic” occurring after the measurements obtained on 5/28/08
would have been construction traffic and winter maintenance operations. Therefore the
10/31/08 test results should represent changes to the surface subsequent to the 5/23/08
testing as a result of recent construction related/winter operations.
The 10/23/07 measurements reflect the friction of the surfaces just after original
diamond grinding and just prior to opening to traffic. The random transverse tined
section (e.g. RTT) is adjacent to the test diamond ground sections and is a 14 yr old
surface.
One of the more remarkable aspects of data presented in Figure 13 is that the
smooth tire results are higher than the ribbed tire results for the diamond ground surfaces.
This not the case for the random transverse tining which exhibits the difference found on
most typical surfaces. At this time this finding is not well understood by the author.
However, for the NGCS section, the data is essentially identical between the 5/28 and
10/23/08 testing as would be expected. This would suggest that the repeatability of the
15. 14
MnDOT testing is very good. Since the NGCS has large lands (see Figure 4), it would
not be expected to change much due to construction traffic or winter maintenance
operations.
The NGCS smooth tire results are essentially the same after five months of traffic
as when it was constructed. This would seem appropriate as the surface is essentially a
“manufactured” surface at the beginning and little change is expected.
The NGCS LITE is a recently developed surface to provide an economical
renewable surface for the NGCS. This surface is intended to develop more micro-texture
on the land area. It is a further development of the NGCS concept. The texture produced
by the NGCS LITE can be produced in the original NGCS construction or it could be
used to “touch-up” the texture on the land if it ever became necessary. The “touch-up”
process could be accomplished very cost effectively since little material is being
removed. It’s intended to re-establish or improve micro-texture.
Figure 13 Friction (SN40) as a Function of Surface Texture and Time
VI Lessons Learned
1 Acoustic Longevity of Diamond Ground Surfaces
One of the questions that arose during evaluation of the NGCS was the expected
acoustic longevity. Since it is less than a year old in implementation, the question could
not be directly answered. Instead as an alternative, it became of interest to benchmark
the existing CDG acoustic longevity. Although this maintenance strategy has been
around since the 1960’s, acoustic longevity curves were not readily available so ACPA
attempted to establish some findings in this regard.
51
36
51
48
44
49
45
49
74
66
57 58
54 55
48
56
0
10
20
30
40
50
60
70
80
Friction (SN40)
Texture Type
Ribbed Tire (SN40R)
Smooth Tire (SN40S)
Random
Transverse
Tined
Next Generation
Concrete Surface
NGCS
LITE
Conventional Diamond
Grinding
Shadow effect indicates
testing at construction
10/31/08
10/23/07
5/28/08
10/31/08
10/23/07
5/28/08
10/31/08 10/31/08
16. 15
With the advent of noise measurement technologies such as OBSI, introduced by
Caltrans into the highway industry in 2002, it became possible to develop acoustic
longevity curves for selected pavements fairly efficiently. The first ACPA attempt at this
occurred during the summer of 2008 on pavements in Kansas. The Kansas Department
of Transportation provided a list of projects and a suggested testing scheme to the ACPA
for OBSI testing. The selected pavements were intended to represent pavements of
similar type, joint design, environment, and traffic, but of various ages. Pavement ages
up to approximately 10 years old were evaluated. Limestone is the predominate
aggregate type found in Kansas and used on these pavement sections. The top size
aggregate is ¾” to reduce D-cracking potential.
Seventeen pavements were tested and the results indicated in Figure 14. As
indicated, there is a poor R2
with the regression equation suggesting that the data is
randomly associated and no trend exists. This indicates that the acoustic performance of
conventional diamond grinding remains almost constant throughout its early life. As
noted, the data only includes pavements up to ten years old. The pavements selected and
tested were all doweled pavements with little or no faulting, of uniform joint design, and
compression sealed joints.
The acoustic durability of the NGCS surfaces placed to date has provided similar
experience as the conventional diamond ground surfaces.
Figure 14 Acoustic Durability of Conventional Diamond Ground Projects in
Kansas
y = 0.047x + 101.58
R² = 0.0619
99.0
100.0
101.0
102.0
103.0
104.0
105.0
106.0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
OBSILevel(dBA)
Pavement Age
17. 16
2 Anisotropic Friction Behavior
The NGCS texture consists of a flush ground surface that has grooves on ½ inch
centers. Although the grooves do not currently provide a significant benefit from a noise
perspective, there is a belief that they would provide additional benefit in regards to wet
weather accidents.
Historically, studies have indicated that grooved pavements have demonstrated
reductions in wet weather accidents and often times with little or no change in ribbed tire
friction values. The conundrum of the increased safety with little or no additional
apparent improvement in friction value has always been difficult to explain.
To investigate this further, the IGGA contracted with MACTEC, Inc. to conduct
friction testing using the California Test Method 342. This rather unique device,
indicated in Figure 15, allows friction to be measured at various angles to the centerline
direction over a reasonable area. With this approach it is possible to gain insight into the
anisotropic friction behavior of selected textures.
One end of the device is attached to the hitch of a pickup truck with a hitch that
allows the device to pivot from directly behind the vehicle (e.g. direction of traffic) to 90
degrees to the centerline. Testing is conducted by lifting the wheel to 6 mm above the
pavement, attaining a speed of 50 mph, dropping the wheel to the pavement, and
measuring the distance the wheel travels along the pavement.
Once the wheel is dropped, there is no additional energy supplied to the wheel so
the kinetic energy of the wheel is transformed into potential energy of the springs that
attempt to restrain the wheel. The distance traveled is a function of the friction level and
kinetic energy of the wheel. Since the kinetic energy of the wheel is always known and
constant, the distance relates directly to the friction level of the surface under
investigation.
Testing was conducted at five angles (e.g. 0, 15, 30, 45, & 90 degrees) at each test
location. Three test locations were obtained for each surface type. For each test location,
except the astro-turf, the 0 degree test was repeated upon completion of the 90 degree test
to evaluate repeatability of the equipment. One hundred and seventeen friction tests were
conducted during the evaluation.
The shortcoming in the data collection effort was that the test procedure requires
testing to be conducted above 40o
F. During the time of year this was conducted, it was
not possible and testing occurred in the 33-35o
F range on pavements of variable wetness.
To minimize the viscosity problem associated with the lower temperatures,
friction was expressed in terms of a friction index as indicated in Figure 16. The friction
index is derived by dividing the friction value obtained at the specified angle by the
friction value obtained at 0 degrees (e.g. the direction of travel). Friction indexes greater
than one indicate an increase in friction compared to the direction of travel and lower
indices, less friction.
18. 17
Figure 15 Photo of California CT-342 Test Device and Selected Angles of Testing
Figure 16 Friction Index as a Function of Deviation from the Direction of Travel
(Uncorrected for Cross Slope)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 10 20 30 40
Friction Index Relative to Friction in Direction of Travel
Deviaton from Direction of Travel (Degrees)
CDG
Random Transverse Tined
Astro Turf
Grooved
19. 18
The grooved textures exhibited an increase in friction as the device was oriented
at an angle to the direction of travel (e.g. anisotropic behavior). This would suggest that
the grooves are providing additional benefit for vehicles attempting to lose control since
the friction increases. The astro-turf and CDG , on the other hand, appeared to behave
more like isotropic surfaces in regards to friction and indicated no apparent difference in
direction. The random transverse tined pavement decreased in friction in regards to
increasing deviation which is consistent with what would be expected as the tines are
already at right angles to the direction of traffic.
At this time these results should be considered preliminary until the experiment
can be repeated under more favorable environmental conditions that allow complete
adherence to the test procedure and employ replication of the results. It should also be
noted that the CT-342 test method uses glycerin on the surface in the test method.
3 NGCS LITE -- The Renewable Surface
As previously mentioned, the NGCS LITE surface was developed to provide
additional micro-texture on existing NGCS surfaces should it become necessary to do so.
With the large land size of the NGCS surface, the texture wear has been assumed to be
less than occurs on conventional diamond ground surfaces. As such it should have
extended life in comparison to CDG. With the advent of the NGCS LITE surface, it
provides an easily renewable surface that can be “touched up” in less time and cost than a
conventional diamond ground surface. Very little material is removed to create this
surface, providing a significantly faster operation. It is intended as a perpetual surface
strategy (PSS).
The first test section of the NGCS LITE surface was constructed in October 2008
and it became too cold to conduct proper OBSI equipment during 2008. Therefore, noise
results will not be available until next spring.
VII Summary and Conclusions
The NGCS diamond ground surface, although only one year in implementation,
has successfully demonstrated that it is a low noise concrete surface. The NGCS,
resembling a “manufactured surface,” provides its low noise benefits when initially
constructed and does not require a wear in period to break the fins down. In the test
sections constructed to date, the NGCS begins approximately 1-4 dBA quieter than a
conventional diamond ground surface and is approximately 0 to1 dBA quieter after the
first year. More time is necessary to establish the acoustic performance of the NGCS
pavement but as with conventional diamond ground surfaces; the acoustic performance is
not expected to change within the first ten years of its construction when implemented on
well designed concrete pavements.
The early friction results of conventional diamond ground surfaces have been
superior to the NGCS surface. The NGCS surface smooth tire results have not changed
since construction while the conventional diamond grind, which started out much higher,
is decreasing. At one year the conventional diamond grind still provides superior and
excellent friction results, as does the NGCS.
20. 19
The potential benefit of anisotropic friction behavior of the NGCS (eg
longitudinally grooved surfaces) surface needs to be further evaluated and verified as this
may provide additional safety to the traveling public.
The ability to improve/maintain the NGCS surface over time is an important
advantage as it provides a renewable maintenance strategy that can be economically
constructed. The efficacy of the PSS will require continued evaluation during 2009.