The document evaluates the physical and mechanical properties of two experimental cements - calcium sulpho-aluminate cement (CSA) and calcium fluoro-aluminate cement (CFA) - and compares them to a proprietary glass ionomer cement. It finds that both experimental cements have adequate setting times and compressive strength compared to glass ionomer cement. CSA performed better than CFA in flexural and compressive strength testing. Adding an inert filler like granite improved flexural strength but reduced compressive strength. Both experimental cements showed potential as dental materials, with CSA performing better than CFA.
Study on effect of Alccofine & Fly ash addition on the Mechanical properties ...ijsrd.com
This paper presents the results of an experimental investigation carried out for M-70 Grad Concrete and to evaluate the compressive strength and Flexural Strength of Concrete. High Performance Concrete is made by partial replacement of cement by alccofine, fly ash, silica fume. In this study the Class F fly ash used in various proportions 20 to 35%, alccofine 4 to 14% and silica fume 4% to 14% by weight of cement. The mix proportions of concrete had a water binder ratio for Alccofine mix concrete 0.30 and Silica-fume mix concrete 0.32.super plasticizer was added based on the required degree of workability. The total binder content was 600 kg/m3. The concrete specimens were cured on normal moist curing under normal atmospheric temperature. The compressive strength was determined at 7 , 28 , 56 days and flexural strength was determined at 28 and 56 days The results indicate the concrete made with these proportions generally show excellent fresh and hardened properties. The addition of Alccofine, silica fume shows early strength gaining property and that of fly ash shows a long term strength. The ternary system that is Portland cement-fly ash-Alccofine concrete was found to increase the compressive strength of concrete on all age when compared to concrete made with Portland cement-fly ash-silica fume.
Effect of Alccofine and Fly Ash Addition on the Durability of High Performanc...ijsrd.com
The aim of this Study is to evaluate the performance of concrete (HPC) containing supplementary cementitious materials such as Fly ash & Alccofine. The necessity of high performance concrete is increasing because of demands in the construction industry. Efforts for improving the performance of concrete over the past few years suggest that cement replacement materials along with Mineral & chemical admixtures can improve the strength and durability characteristics of concrete. Alccofine (GGBS) and Fly ash are pozzolanic materials that can be utilized to produce highly durable concrete composites. This study investigates the performance of concrete mixture containing Local Alccofine. in terms of Compressive strength, Sulphate Attack tests, Alkali test and RCPT (Rapid chloride penetration test) at age of 28 and 56 days. In addition find out the optimum dosage of alccofine and fly ash from that get M70 Strength, in final mix proportion perform a given test. Result show that concrete incorporating Alccofine and fly ash had higher compressive strength and alccofine enhanced the durability of concretes and reduced the chloride diffusion. An exponential relationship between chloride permeability and compressive strength of concrete is exhibited.
Durability Studies of Fly Ash Based Geopolymer ConcreteIJERA Editor
A detailed study on the durability of geopolymer concrete has been done. Geopolymer concrete is an
environment friendly concrete which has lower carbon footprint as compared to that of conventional concrete. In
this study, cement has been replaced by fly ash and the properties such as compressive strength, sulphur
resistance, acid resistance, water absorption, sorptivity and chloride attack have been studied. Class F fly ash has
been used and geopolymer concrete was heat cured for 24 hours under 75◦C. It was observed that use of
geopolymer in concrete not only reduces its greenhouse footprint but, also increases its strength and resistivity
to harmful acids.
A Study on Partial Replacement of Natural Granite Aggregate with Pelletized F...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Study on effect of Alccofine & Fly ash addition on the Mechanical properties ...ijsrd.com
This paper presents the results of an experimental investigation carried out for M-70 Grad Concrete and to evaluate the compressive strength and Flexural Strength of Concrete. High Performance Concrete is made by partial replacement of cement by alccofine, fly ash, silica fume. In this study the Class F fly ash used in various proportions 20 to 35%, alccofine 4 to 14% and silica fume 4% to 14% by weight of cement. The mix proportions of concrete had a water binder ratio for Alccofine mix concrete 0.30 and Silica-fume mix concrete 0.32.super plasticizer was added based on the required degree of workability. The total binder content was 600 kg/m3. The concrete specimens were cured on normal moist curing under normal atmospheric temperature. The compressive strength was determined at 7 , 28 , 56 days and flexural strength was determined at 28 and 56 days The results indicate the concrete made with these proportions generally show excellent fresh and hardened properties. The addition of Alccofine, silica fume shows early strength gaining property and that of fly ash shows a long term strength. The ternary system that is Portland cement-fly ash-Alccofine concrete was found to increase the compressive strength of concrete on all age when compared to concrete made with Portland cement-fly ash-silica fume.
Effect of Alccofine and Fly Ash Addition on the Durability of High Performanc...ijsrd.com
The aim of this Study is to evaluate the performance of concrete (HPC) containing supplementary cementitious materials such as Fly ash & Alccofine. The necessity of high performance concrete is increasing because of demands in the construction industry. Efforts for improving the performance of concrete over the past few years suggest that cement replacement materials along with Mineral & chemical admixtures can improve the strength and durability characteristics of concrete. Alccofine (GGBS) and Fly ash are pozzolanic materials that can be utilized to produce highly durable concrete composites. This study investigates the performance of concrete mixture containing Local Alccofine. in terms of Compressive strength, Sulphate Attack tests, Alkali test and RCPT (Rapid chloride penetration test) at age of 28 and 56 days. In addition find out the optimum dosage of alccofine and fly ash from that get M70 Strength, in final mix proportion perform a given test. Result show that concrete incorporating Alccofine and fly ash had higher compressive strength and alccofine enhanced the durability of concretes and reduced the chloride diffusion. An exponential relationship between chloride permeability and compressive strength of concrete is exhibited.
Durability Studies of Fly Ash Based Geopolymer ConcreteIJERA Editor
A detailed study on the durability of geopolymer concrete has been done. Geopolymer concrete is an
environment friendly concrete which has lower carbon footprint as compared to that of conventional concrete. In
this study, cement has been replaced by fly ash and the properties such as compressive strength, sulphur
resistance, acid resistance, water absorption, sorptivity and chloride attack have been studied. Class F fly ash has
been used and geopolymer concrete was heat cured for 24 hours under 75◦C. It was observed that use of
geopolymer in concrete not only reduces its greenhouse footprint but, also increases its strength and resistivity
to harmful acids.
A Study on Partial Replacement of Natural Granite Aggregate with Pelletized F...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
An Experimental Investigation of Use of Phosphogypsum and Marble Powder for M...IJERA Editor
In this paper, the detailed experimental investigation was done to study the effect of partial replacement of ce-ment by phosphogypsum (PG) and marble powder (MP) in combine proportion started from 5% PG and 25% MP mix together in concrete by replacement of cement with the gradual increase of PG by 5% upto 15% whe-reas MP is constant at 25%.Last proportion was taken after decreasing PG by 5% and increasing MP by 10%. The tests on hardened concrete were destructive in nature which includes compressive test on cube for size (150 x 150 x 150 mm) at 7, 14 and 28 days of curing as per IS: 516 1959, Flexural strength on beam (150 x 150 x700 mm) at 28 days of curing as per IS: 516 1959 and split tensile strength on cylinder (150 mm ø x 300mm) at 28 days of curing as per IS: 5816 1999. The work presented in this paper reports the effects on the behavior of con-crete produced from cement with combination of PG and MP at different proportions on the mechanical proper-ties of concrete such as compressive strength, flexural strength, and split tensile strength. Investigation reported that compressive strength decreases by 16.89% in compared with targeted strength and decreases by 12.78% compared with control concrete at 28 days, flexural strength decreases by 26.46% compared with control con-crete at 28 days, split tensile strength increases by 10.833% compared with conventional concrete at 28 days, were obtained at combination of (5% PG and 25% MP). Partial replacement of PG and MP reduces the envi-ronmental effects, produces economical and eco-friendly concrete.
Experimental Investigations on Fresh Properties of Binary and Ternary Blended...AbdulRazakBH
Abstract--- Binder-chemical admixture compatibility plays a vital role in deciding the performance of concrete especially in the fresh state. Optimum dosage of chemical admixture is helpful in controlling various fresh properties of Self Compacting Concrete(SCC) and avoiding the problems of segregation and bleeding in blended concrete with mineral admixtures such as Ground granulated Blast Furnace Slag(GGBS) and Alccofine(Ultrafine GGBS). The study focusses on optimization of chemical admixture dosage for binary and ternary blended concrete for the production of SCC. Various combinations of binary blended concrete and ternary blended concrete along with control mix(only OPC) are tested for workability properties for passing ability, filling ability and and resistance to segregation(V-Funnel Time). It was observed that concrete containing higher GGBS required lesser dosage of chemical admixture for satisfying workability properties as per EFNAARC guidelines. Alccofinewas added at 5% to compensate for hardened properties.
Keywords--- Ground Granulated Blast Furnace Slag (GGBS), Alccofine, Self Compacting Concrete (SCC).
Abstract
The paper presents the studies on properties of blended concretes containing various mineral admixtuers like fly ash, silica fume, ground granulated blast furnace slag and metakaolin as partial replacement to cement. By addition of these admixtures reduces the cement content so that it can minimize the enivornment impact from the producion of cement.Various properties of blended concretes are reviewed from different research articles.
Keywords- Blended Concrete, Binary Blended, Triple Blended, Quaternary Blended Concretes, Strength Properties, Durability Properties
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Evaluation of strength and performance characteristics of cold mix bitumen us...IJLT EMAS
An attempted has been made to evaluate the strength
and performance characteristics of cold mix bitumen using
reclaimed asphalt. An experimental result obtained from
laboratory testing of the physical and mechanical parameters of
the recycled material, in which the material from the existing
pavement layers were analyses. The air void content, Marshall
stability and flow of the recycled mixtures were investigated. The
tests were performed on the road base mixtures incorporating
reclaimed asphalt pavement (RAP) with bituminous emulsion. It
was observed that the reclaimed asphalt was having impact
strength of 10%, crushing strength of 8.2%. It is significant to
note that the reclaimed aggregate which was subjected to loading
condition already was still showing very good strength properties.
The maximum stability obtained from optimum binder content
was 384 kg which is a very good value for a cold mix made up of
reclaimed asphalt aggregate. The flow value obtained was also
5.06 mm as observed. The aim of the tests was to evaluate the
properties of the mixes in terms of the recycled aggregates.
Satisfactory results were obtained.
STUDY ON EFFECT OF HYBRID FRP LAMINATES WRAPPED EXTERNALLY (U-WRAP) ON REINFO...IAEME Publication
Recently fibre reinforced polymer composite material namely glass FRP, carbon FRP, basalt FRP etc, is being used as strengthening material. Each technique has its own merits and limitations. Experimental study have been conducted on Reinforced concrete beams which are externally strengthened with GFRP and CFRP as double layer one above the other and it is referred as Hybrid FRP techniques is attained with epoxy resin as adhesive compound. All the ingredients in the beam specimens were maintained with same consistency. A total six beams were cast for the experimental investigation. Out of that three were kept as control specimens and the remaining three were strengthened with double layer of CFRP and GFRP in the U-Wrap pattern. From the overall experimental investigation it can be observed that there is an appreciable increase in ultimate load carrying capacity of the beams strengthened with hybrid FRP laminates.
Effect of Nanoclay on the Structure and Properties of High Density Polyethyle...iosrjce
In this study we prepared high density polyethylene (HDPE)/ clay nanocomposites by melt
compounding in a twin screw extruder with rotational speed of 50rpm and the temperatures of the zones are set
to 180-210°C.Different screw configuration have been used to study the effect of screw elements on the
properties of nanocomposites. screw configuration changed from dispersive to distributive type. Cloisite 15A
was used as the filler and weight percent of clay was fixed to 3wt%. Maleated polyethylene grafted polyolefins
supplied from Reliance ltd. A new combination of maleic anhydride grafted polyethylene prepared in our lab
through grafting also taken as compatibilizer.the samples were then characterized by XRD,FTIR and DSC. The
results showed that PE/clay nanocomposites provide better exfoliation with high dispersive screw
configuration. The addition of clay also increased the dispersion and crystallinity of the composite. The clay
particles helped the nanocomposites to develop toruos path that prevent the leakage of gas through it.
Rheological results indicated an increase in the viscosity with the addition of nano clay to PE. wide angle x-ray
diffraction shows the better exfoliation of nano particle clays in the polymer matrix. The mechanical, thermal
and rheological characteristics were measured by using differential scanning calorimetry (DSC), X-ray
diffraction (XRD). XRD indicates that Compatibilizer –nanoclay ratio plays an important role in the exfoliation
of clay in the polyethylene.
Conocer las vocales a través de actividades lúdicas pedagógicas apoyadas con herramientas tic para afianzar los conocimientos de los alumnos del grado preescolar
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
An Experimental Investigation of Use of Phosphogypsum and Marble Powder for M...IJERA Editor
In this paper, the detailed experimental investigation was done to study the effect of partial replacement of ce-ment by phosphogypsum (PG) and marble powder (MP) in combine proportion started from 5% PG and 25% MP mix together in concrete by replacement of cement with the gradual increase of PG by 5% upto 15% whe-reas MP is constant at 25%.Last proportion was taken after decreasing PG by 5% and increasing MP by 10%. The tests on hardened concrete were destructive in nature which includes compressive test on cube for size (150 x 150 x 150 mm) at 7, 14 and 28 days of curing as per IS: 516 1959, Flexural strength on beam (150 x 150 x700 mm) at 28 days of curing as per IS: 516 1959 and split tensile strength on cylinder (150 mm ø x 300mm) at 28 days of curing as per IS: 5816 1999. The work presented in this paper reports the effects on the behavior of con-crete produced from cement with combination of PG and MP at different proportions on the mechanical proper-ties of concrete such as compressive strength, flexural strength, and split tensile strength. Investigation reported that compressive strength decreases by 16.89% in compared with targeted strength and decreases by 12.78% compared with control concrete at 28 days, flexural strength decreases by 26.46% compared with control con-crete at 28 days, split tensile strength increases by 10.833% compared with conventional concrete at 28 days, were obtained at combination of (5% PG and 25% MP). Partial replacement of PG and MP reduces the envi-ronmental effects, produces economical and eco-friendly concrete.
Experimental Investigations on Fresh Properties of Binary and Ternary Blended...AbdulRazakBH
Abstract--- Binder-chemical admixture compatibility plays a vital role in deciding the performance of concrete especially in the fresh state. Optimum dosage of chemical admixture is helpful in controlling various fresh properties of Self Compacting Concrete(SCC) and avoiding the problems of segregation and bleeding in blended concrete with mineral admixtures such as Ground granulated Blast Furnace Slag(GGBS) and Alccofine(Ultrafine GGBS). The study focusses on optimization of chemical admixture dosage for binary and ternary blended concrete for the production of SCC. Various combinations of binary blended concrete and ternary blended concrete along with control mix(only OPC) are tested for workability properties for passing ability, filling ability and and resistance to segregation(V-Funnel Time). It was observed that concrete containing higher GGBS required lesser dosage of chemical admixture for satisfying workability properties as per EFNAARC guidelines. Alccofinewas added at 5% to compensate for hardened properties.
Keywords--- Ground Granulated Blast Furnace Slag (GGBS), Alccofine, Self Compacting Concrete (SCC).
Abstract
The paper presents the studies on properties of blended concretes containing various mineral admixtuers like fly ash, silica fume, ground granulated blast furnace slag and metakaolin as partial replacement to cement. By addition of these admixtures reduces the cement content so that it can minimize the enivornment impact from the producion of cement.Various properties of blended concretes are reviewed from different research articles.
Keywords- Blended Concrete, Binary Blended, Triple Blended, Quaternary Blended Concretes, Strength Properties, Durability Properties
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Evaluation of strength and performance characteristics of cold mix bitumen us...IJLT EMAS
An attempted has been made to evaluate the strength
and performance characteristics of cold mix bitumen using
reclaimed asphalt. An experimental result obtained from
laboratory testing of the physical and mechanical parameters of
the recycled material, in which the material from the existing
pavement layers were analyses. The air void content, Marshall
stability and flow of the recycled mixtures were investigated. The
tests were performed on the road base mixtures incorporating
reclaimed asphalt pavement (RAP) with bituminous emulsion. It
was observed that the reclaimed asphalt was having impact
strength of 10%, crushing strength of 8.2%. It is significant to
note that the reclaimed aggregate which was subjected to loading
condition already was still showing very good strength properties.
The maximum stability obtained from optimum binder content
was 384 kg which is a very good value for a cold mix made up of
reclaimed asphalt aggregate. The flow value obtained was also
5.06 mm as observed. The aim of the tests was to evaluate the
properties of the mixes in terms of the recycled aggregates.
Satisfactory results were obtained.
STUDY ON EFFECT OF HYBRID FRP LAMINATES WRAPPED EXTERNALLY (U-WRAP) ON REINFO...IAEME Publication
Recently fibre reinforced polymer composite material namely glass FRP, carbon FRP, basalt FRP etc, is being used as strengthening material. Each technique has its own merits and limitations. Experimental study have been conducted on Reinforced concrete beams which are externally strengthened with GFRP and CFRP as double layer one above the other and it is referred as Hybrid FRP techniques is attained with epoxy resin as adhesive compound. All the ingredients in the beam specimens were maintained with same consistency. A total six beams were cast for the experimental investigation. Out of that three were kept as control specimens and the remaining three were strengthened with double layer of CFRP and GFRP in the U-Wrap pattern. From the overall experimental investigation it can be observed that there is an appreciable increase in ultimate load carrying capacity of the beams strengthened with hybrid FRP laminates.
Effect of Nanoclay on the Structure and Properties of High Density Polyethyle...iosrjce
In this study we prepared high density polyethylene (HDPE)/ clay nanocomposites by melt
compounding in a twin screw extruder with rotational speed of 50rpm and the temperatures of the zones are set
to 180-210°C.Different screw configuration have been used to study the effect of screw elements on the
properties of nanocomposites. screw configuration changed from dispersive to distributive type. Cloisite 15A
was used as the filler and weight percent of clay was fixed to 3wt%. Maleated polyethylene grafted polyolefins
supplied from Reliance ltd. A new combination of maleic anhydride grafted polyethylene prepared in our lab
through grafting also taken as compatibilizer.the samples were then characterized by XRD,FTIR and DSC. The
results showed that PE/clay nanocomposites provide better exfoliation with high dispersive screw
configuration. The addition of clay also increased the dispersion and crystallinity of the composite. The clay
particles helped the nanocomposites to develop toruos path that prevent the leakage of gas through it.
Rheological results indicated an increase in the viscosity with the addition of nano clay to PE. wide angle x-ray
diffraction shows the better exfoliation of nano particle clays in the polymer matrix. The mechanical, thermal
and rheological characteristics were measured by using differential scanning calorimetry (DSC), X-ray
diffraction (XRD). XRD indicates that Compatibilizer –nanoclay ratio plays an important role in the exfoliation
of clay in the polyethylene.
Conocer las vocales a través de actividades lúdicas pedagógicas apoyadas con herramientas tic para afianzar los conocimientos de los alumnos del grado preescolar
Primary Evidence - Ancient Egyptians came from Inner Africaafricaonline1
Ancient Text from Egypt reveals that the Ancient Egyptians sourced their Ancestors to inner Africa and that the Famine Stele is the oldest interaction between God and Man and was most likely the source of many Biblical Stories. The Hebrews by their own records source their entry into Egypt around the 12th Dynasty. They would not have been sheltered from the Famine Stele and its revelation that Khnum (The Potter Wheel God) had a dramatic interaction with Djoser/Neterkhet. Plates of inner Africa taken from Michael Tellinger's Book - Temples of the African Gods. Presented at 31st annual ASCAC Conference held at Essex County College, Newark New Jersey.
The Blueprint for Black Sovereignty by Bro. Reggieafricaonline1
The City is the Governmental Idea that controls Black Citizenship or not. The Road not taken is to completely by the power of Black Organization to completely control Cities. It is in the City where our Inalienable Rights and Pursuit of Happiness lays. It is the City that controls every aspect of Black Life.
The latest update on what Sensor Access Technology can offer in cutting edge solutions with smart card technology, Biometrics, CCTV integration, PoE and much more, Wireless Locking and much more.
To Study the Properties of Self-Compacting Concrete Using Recycled Aggregate ...paperpublications3
Abstract: This paper investigates the study of workability and durability characteristics of Self-Compacting Concrete (SCC) with Viscosity Modifying Admixture (VMA), and containing fly ash. The mix design for SCC was arrived as per the Guidelines of European Federation of National Associations Representing for Concrete (EFNARC). In this investigation, SCC was made by usual ingredients such as cement, fine aggregate, coarse aggregate, water, mineral admixture fly ash and demolished concrete at various replacement levels (5%, 10%, 15%, and 20%). To enhance the property of SCC made with the use of demolish concrete and fly ash, glass fiber has been added to the mix. Glass fiber in various % (i.e. 0.15%, 0.20% 0.30%, of Wt. of cement) has been added in the mix which contain demolish concrete and gave highest strength i.e. (10% demolish concrete).
Cement is the main construction material for making concrete. It provides good bonding between aggregates and also provides strength. But at the time of manufacturing, cement releases high amount of CO2. In order to reduce the environmental impact and to improve the property of concrete, Palm ash concrete are used. Palm ash concrete containing palm ash as partial substitute for cement. The replacement percentages are 10%, 20%, 30%. In these investigations, compressive strength and durability of palm ash concrete and normal concrete were found out. Results are tabulated and discussed. The properties of palm ash concrete are also compared with the conventional concrete. The palm ash concrete is very economical and also ecofriendly concrete
Aging is one of the real issues
service life of pavement. The
change after a period of time
service life and when exposed to the
this study local materials
including asphalt cement,
Portland cement and silica fume were used as mineral filler. Two types of specimens
were prepared and tested
mineral filler and the second
fume as mineral filler. The optimum asphalt content of mixture
to Marshall Design method. Optimum asphalt c
specimens that contain 100 % Portland cement as mineral filler and it was 5.1 % for
specimens that contain 50 % Portland cement and 50 % silica fume as mineral filler
Fifty one (51) of asphalt concrete specimens (Marshall Spe
For the purpose of studying the effect of short term aging, part of specimens was
placed in the oven and subjected it to a temperature of 135 ºC for (2 and 4 hr), while
for the long term aging, another part of specimens was placed in
subjected it to a temperature of 85 ºC for 72 hr (3 days) and 120 hr (5 days) according
to AASHTO R30. The results of Marshall Test showed that the stability
was increased by 13.63%, 27.27%, 51, 81 and 63.63% after
after L.T.A(3 and 5) days, respectively. Flow
and 4) hr and after L.T.A (
respectively. Also, the results showed that the air voids in total mixture were
after short and long term aging. Generally, the results showed that the use of 50%
silica fume as a mineral filler with 50 %Portland cement leads to
of aging on properties of Marshall
A Study on Partial Replacement of Natural Granite Aggregate with Pelletized F...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Acid resistance and corrosion protection potential of concrete prepared with aTalalSalem5
An experimental investigation was conducted on two key aspects of the durability characteristics of concrete
materials prepared with an alkali aluminosilicate hydraulic cement and with Portland cement, both cured at
room temperature. The durability characteristics evaluated concerned the acid resistance of concrete, and its
ability to protect the embedded reinforcing steel against corrosion under wet-dry cycles. Acid resistance was
evaluated through monitoring of mass and strength change over time under acid attack, visual observations, and
scanning electron microscopy (SEM). Corrosion resistance was evaluated through measurement of the corrosion
potential, visual observations and scanning electron microscopy. The acid resistance and corrosion protection
potential of the concrete prepared with the alkali aluminosilicate cement were found to be superior to those of
Portland cement concrete.
Experimental Study on Durability Characteristics of High Performance Concrete...theijes
High performance concrete (HPC) is developed gradually over the last 15 years with respect to production of concrete with higher and higher strength. To enhance the properties such as durability, strength, workability, economy has increased due to the usage of mineral admixtures in making high performance concrete. The scope of the present study is to investigate the effect of mineral admixtures and by-products towards the performance of HPC. An effort has been made to concentrate on the mineral admixture of silica fume towards their pozzolanic reaction and industrial by-product of bottom ash and steel slag towards their hydration reaction can be contributed towards their strength and durability properties. The strength characteristics such as compressive strength, tensile strength and flexural strength were investigated to find the optimum replacement of mineral admixture and by-product admixture. HPC with mineral admixture of silica fume at the replacement levels of 0%, 5%, 10%, 15% & 20% were studied at the age of 28 days and industrial by-products of bottom ash and steel slag aggregate at the replacement level of 10%, 20%, 30%, 40% & 50% were studied at the age of 28 days. There were a total of 15 mixes created with different material contents. Out of 14 were HPC mixes and 1 were conventional concrete mixes. Finally strength has enhanced with the mix of silica fume can replaced by cement with 5% and bottom ash and steel slag can replaced by fine and coarse aggregate with 10% can be achieved higher strength when compared with other percentage of mixes. The combination mixes can be classified as binary and ternary mixes. Binary mixes involved combinations of silica fume and bottom ash (SF+BA), silica fume and steel slag aggregate (SF+SSA), bottom ash and steel slag aggregate (BA+SSA) and Ternary mixes involved combination of three materials such as silica fume, bottom ash and steel slag aggregate (SF+BA+SSA) in High performance concrete. The investigation revealed that the combined use of silica fume, bottom ash and steel slag aggregate improved the mechanical properties of HPC and thus there 3 materials may use as a partial replacement material in making HPC. The durability studies such as acid resistance, salt resistance, sulphate resistance & water absorption were conducted. From the experimental investigation, it was observed that mineral admixture of silica fume and industrial by-products of bottom ash & steel slag aggregate plays a vital role in improving the strength and durability parameter itself.
Contents
Introduction
Basic concept & context of Work
Objective of Work
Literature Review
Fly Ash
Mix Design
Compressive Strength of Concrete
Experimental Work
Cylinder Select
Sample Preparation
Used Materials
Concreting
Curing
Laboratory Test
Result and Analysis
Conclusion
Employing of novel poly (amine-ester) with Pentaerithritol core as a new poly...IJERA Editor
A novel hyperbranched poly (amine-ester) (HBPAE) with a high number of hydroxyl end groups has been prepared and successfully applied as new polymeric admixture for ordinary Portland cement (OPC) after its complete characterization via GPC, IR, 1H-NMR, TGA and DSC. The effect of polymer addition on the cement paste was investigated by measuring the effect of 1, 3 and 5 wt. % HBPAE solutions on the properties of OPC. The results clarified that the addition of HBPAE to OPC pastes decreased the water of consistency while increased the compressive strength with no effect on the chemical composition of the cement phase. The SEM images indicated that the incorporation of HBPAE in cement phase affected the physical state, shape, size, morphology and microstructure of the formed hydrates. Generally, the addition of hyperbranched poly amine-ester (HBPAE) improved the physico-mechanical properties of cement.
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June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
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Digital Tools and AI for Teaching Learning and Research
2008 iej 4
1. Modification of mineral trioxide aggregate. Physical
and mechanical properties
J. Camilleri
Department of Building and Civil Engineering, Faculty of Architecture and Civil Engineering; Faculty of Dental Surgery, University
of Malta, Malta
Abstract
Camilleri J. Modification of mineral trioxide aggregate.
Physical and mechanical properties. International Endodontic
Journal, 41, 843–849, 2008.
Aim To evaluate the physical and mechanical prop-
erties of two cements with a similar chemical compo-
sition to mineral trioxide aggregate and to attempt to
improve their properties by producing a composite
material.
Methodology Two cement types were used: a mix-
ture of calcium sulpho-aluminate cement and Portland
cement (CSA) and calcium fluoro-aluminate cement
(CFA) in conjunction with an admixture to improve the
handling characteristics. Cements were mixed with an
inert filler to produce cement composite. The setting
time of the cements was evaluated using an indentation
technique. The flexural and uni-axial compressive
strengths and solubility of the cements and cement
composites were evaluated. The properties of the
materials were compared with proprietary brand
glass–ionomer cement.
Results The setting time of the CSA and CFA cements
was less than 6 min. The use of an admixture to
improve the handling properties tended to retard
setting. CSA was stronger then CFA in both compres-
sion and flexure (P < 0.001). Addition of granite
increased the flexural strength of both cements but
reduced the compressive strength (P < 0.01). CFA
absorbed more water then CSA. Addition of granite
reduced the water uptake of both cements.
Conclusions Both CSA and CFA cements had ade-
quate setting times and compressive strength values
when compared with proprietary brand glass–ionomer
cement. CSA was superior to CFA and had more
promise as a prospective dental material.
Keywords: accelerated cements, compressive stre-
ngth, flexural strength, Portland cement, setting time.
Received 31 January 2008; accepted 4 April 2008
Introduction
Mineral trioxide aggregate (MTA) is composed of Port-
land cement and bismuth oxide (Torabinejad & White
1995). MTA was developed as a root-end filling material
following apicectomy and to repair root perforations (Lee
et al. 1993, Pitt Ford et al. 1995). The material has been
used successfully in this regard and indeed, its use has
been extended. For example, MTA has been reported to
be suitable for use as a pulp capping agent (Pitt Ford et al.
1996, Bakland 2000); as a dressing over pulpotomies of
permanent (Holland et al. 2001) and primary teeth
replacing the formocresol pulpotomy procedure
(Eidelman et al. 2001); for obturation of retained
primary teeth (O’Sullivan & Hartwell 2001), and
permanent immature (Hayashi et al. 2004) and mature
teeth (Vizgirda et al. 2004); for single visit apexification
procedures for immature teeth with necrotic pulps
(Whiterspoon & Ham 2001), thus acting as an apical
barrier material (Shabahang & Torabinejad 2000); and
as a root canal sealer cement (Holland et al. 1999,
Geurtsen 2000). Unfortunately, MTA has limited
applications in operative dentistry because of its long
setting time and low compressive strength compared
Correspondence: Dr Josette Camilleri, PhD, Department of
Building and Civil Engineering, Faculty of Architecture and
Civil Engineering, University of Malta, Malta (Tel.: 00356
2340 2870; fax: 00356 21330190; e-mail: josette.camilleri
@um.edu.mt).
doi:10.1111/j.1365-2591.2008.01435.x
ª 2008 International Endodontic Journal International Endodontic Journal, 41, 843–849, 2008 843
2. with other materials (Torabinejad et al. 1995). The
extended endodontic uses and its potential use in
operative dentistry necessitate the development of a
new formulation of the material based on Portland
cement, which optimizes both its strength and its setting
time without compromising its biocompatibility.
Portland cement takes a minimum of 4 h to achieve
a final set (Taylor 1997). The rate of reaction is
controlled by the calcium sulphate (gypsum) which is
added by the manufacturer for that purpose. The
calcium sulphate reacts with the tricalcium aluminate
in Portland cement to produce a high-sulphate calcium
sulpho-aluminate (ettringite). In the absence of calcium
sulphate, the tricalcium aluminate forms a hydrated
calcium aluminate of cubic structure leading to a flash
set. Thus, the calcium sulphate is added by the
manufacturer to avoid the formation of the hydrated
calcium aluminate thus delaying the hydration mech-
anism (Taylor 1997).
The setting time of Portland cement can be reduced
by addition of an accelerator, the removal of gypsum
from the cement and addition of calcium aluminate
cement (Neville 1981). Removal of gypsum results in a
flash set which can be controlled by superplasticizing
admixtures (Camilleri et al. 2005). When calcium
aluminate cement is added to Portland cement the
former reacts to the calcium sulphate (gypsum) in the
Portland cement leaving the tricalcium aluminate free
to flash set, thus resulting in a shorter setting time
(Neville & Wainwright 1975). Cements produced by
addition of calcium aluminate cement to Portland
cement have a reduced compressive strength (Camilleri
et al. 2006). The compressive strength of the cement
can be improved by reduction in the water to cement
ratio. This is achieved through the use of super-
plasticing admixtures. The plasticizing action of
water reducers is related to their adsorption and
dispersing effects in the cement–water system (Hattori
1978).
The aim of the study was to test the suitability of two
cement types based on Portland cement and to improve
their properties by admixing them with an inert
material. The physical and mechanical properties of
these materials were evaluated and compared with
proprietary brand glass–ionomer cement.
Materials and methods
Two cement types were used:.
1. CSA: calcium sulpho-aluminate cement mixed in
the following proportions
• 3 parts calcium aluminate (Lafarge Special Cements,
Nottingham, UK)
• 8 parts white Portland cement (Lafarge Asland,
Valencia, Spain)
• 1 part synthetic anhydrite (Lafarge Special Cements,
Nottingham, UK)
2. CFA: calcium flouro-aluminate cement (Italcementi
SPA, Bergamo, Italy).
A super-plasticizing admixture (Degussa Construc-
tion Chemicals, Manchester, UK) was added to the
mixing water to increase the workability of the mix and
also to reduce the amount of water required by the
cement during mixing. A cement composite made up of
the cement mixed with granite (Halmann, Iklin, Malta)
was also tested (CSAG, CFAG). The granite used was
obtained by grinding a slab to very fine particles
retained on a 150 lm sieve. The proportion of cement
and granite was calculated using the Theory of Particle
Admixtures (Dewar 1999). Glass–ionomer cement
(GIC; Ketac Molar, 3M Seefeld, Germany) was used as
the control.
Setting time of cements
The setting time of the cements with and without the
addition of the super-plasticizing admixture was tested
using the Vicat apparatus (British Standard Institution
2005b). Four hundred grams of the cement was mixed
with water on a moistened aluminum tray with a small
trowel at a water/cement ratio of 0.25 as suggested by
the manufacturer. The super-plasticizing admixture
was added at the end of the mixing process. The dosage
was adjusted to 0.8 L per 100 kg of cement, again as
suggested by the manufacturer. The mix was then
compacted in a two-part brass mould and initial and
final setting times were determined. The Vicat assembly
was placed in an incubator at 37 °C. The test was
repeated thrice.
Flexural and compressive strength
The flexural and compressive strengths of the cements
were tested according to British Standard Institution
(2005a). A total of 270 g of cement was mixed
thoroughly with water at the pre-determined water/
cement ratio for 2 min. The cement was then loaded
into a prism mould 40 · 40 · 160 mm in size previ-
ously coated with mould oil (Separol, Sika, Switzer-
land). The cement was compacted in two layers and a
vibrating table was used during the compaction to
avoid air entrapment in the cement mix. After casting
MTA modification Camilleri
International Endodontic Journal, 41, 843–849, 2008 ª 2008 International Endodontic Journal844
3. was complete, the moulds were covered with a plastic
sheet to avoid loss of moisture and the cements were
allowed to cure for 24 h. Twenty-four prisms were cast
of each cement type. They were then removed from the
mould and cured at 37 °C in water. Flexural strength
as performed after 1 day, and then after 7, 28 and
56 days. The prisms were mounted in a flexure testing
jig. This jig allowed for 3-point bending to be
performed. The distance between the lower rollers
was 100 mm and the upper roller was placed in the
middle. The flexure jig was mounted between the
platens of a compression machine (Controls spa,
Bergamo, Italy). A 15 kN load cell was used and the
load applied was accurate to 0.1%. The cements were
loaded at 50 N s)1
until they failed. Flexural strength
was calculated using the following formula:
Rf ¼
1:5  Ff  l
b3
where Rf is the flexural strength in N mm)2
, Ff is the
load applied to the middle of the prism at fracture, l is
the distance between the supports in mm and b is the
side of the square section in mm.
After flexural strength was determined the prism
halves were tested in compression at 14.4 kN s)1
. A
250 kN load cell was used for this test with an
accuracy up to 0.1%. Compressive strength was
calculated using the following formula:
Rc ¼
Fc
1600
where Rc is the compressive strength in N mm)2
, Fc is
the maximum load at fracture in N,
1600 = 40 mm · 40 mm is the area of the platens in
mm2
.
In addition to the cements, cement composite was
also tested. The composite was produced by addition of
granite to the two cement types.
Preliminary tests to establish the relative density
(British Standard Institution 1999b), the loose bulk
density (British Standard Institution 1998), the mois-
ture content (British Standard Institution 1999a) and
the water absorption (British Standard Institution
2000) of the granite were performed. Tests on cement
were carried out to establish the relative density (British
Standard Institution 1992), the moisture content
(British Standard Institution 1999a) and the fineness
(British Standard Institution 1992). After performing
the preliminary tests on the cements and aggregate, the
proportion of granite to cement was deduced using the
Theory of Particle Admixtures (Dewar 1999). Quanti-
ties of each material required to achieve the best
particle packing and optimal physical properties were
thus calculated. The cement composite was tested in
both flexure and compression in the same way as
described for the cements.
Solubility
The solubility of CSA, CFA, granite admixed cements
(CSAG, CFAG) and glass–ionomer cement was calcu-
lated by measuring the water uptake of the cements.
Twelve samples each 10 mm in diameter and 2 mm
thick were made for each cement type. Six were cured
in water and the rest were cured at 100% humidity at
37 °C. The weight of the samples was recorded after 1,
7, 28 and 56 days.
Statistical analysis
For all tests carried out, the data were evaluated using
statistical package for the social sciences (SPSS
Inc., Chicago Ill, USA) software. The distribution was
first evaluated to determine the appropriate statistical
test. The data were plotted and the distribution curve
was analysed together with the Kolmogorov–Zmirnov
test with P = 0.05. The P-value of >0.05 signified a
normal distribution and thus parametric tests were
performed. With normally distributed data, analysis
of variance (anova) with P = 0.05 was performed
to evaluate variations between the means. Then
two-tailed independent sample t-tests at 95% confidence
level with P = 0.05 was used to analyse the data.
Results
Setting time of cements
The setting times of the cements is shown in Table 1.
Both cement types had a very rapid set, with CFA
setting faster than CSA; however, this difference was
Table 1 Means of initial and final setting times of different
cement types ± SD (n = 3)
Cement
type
Water
%
Admixture %
weight of
fine material
Initial set
minutes
Final set
minutes
CSA 28 0.5 2.41 ± 0.37 4.05 ± 0.09
CFA 27 0.5 1.83 ± 0.29 3.08 ± 0.14
CSA and
admixture
25 0.5 3.67 ± 0.14 5.25 ± 0.25
CFA and
admixture
25 0.5 3.05 ± 0.18 5.42 ± 0.14
Camilleri MTA modification
ª 2008 International Endodontic Journal International Endodontic Journal, 41, 843–849, 2008 845
4. not statistically significant. The use of a super-plasti-
cizing admixture retarded the final setting time of the
cements, reduced the water required by the cements
and improved the handling properties.
Flexural and compressive strength
The results for the physical properties of the cements
and aggregate are shown in Table 2. The moisture
content of the cements was minimal, thus they were
used without desiccation. The quantities of material
required to produce the cement composite as calculated
by the Theory of Particle Admixtures (Dewar 1999) are
shown in Table 3.
The results for the flexural strength testing of the
cements are shown in Fig. 1a and for the compressive
strength tests in Fig. 1b. The CSA cement was stronger
than the CFA cement both in compression and in
flexure at all curing times (P < 0.001) except for
flexural strength at 1 day where no difference between
the two cements was demonstrated (P > 0.05). Addi-
tion of granite to the CSA cement resulted in an
increase in flexural strength at 28 and 56 days but a
reduction in the compressive strength at all ages
(P < 0.001). Addition of granite to CFA increased the
flexural strength up to 28 days (P < 0.01) but the
flexural strengths of the cement and the cement
composite were the same at 56 days (P > 0.05). The
compressive strength of the calcium fluoro-aluminate
cement did not change markedly with addition of
granite. All the cements tested failed in the normal
mode.
Solubility
The results for the water uptake and loss of the cements
and cement composites is shown in Table 4. The CFA
cement absorbed more water than the CSA cement at
all ages (P < 0.01). Both cement composites absorbed
less water in comparison with the parent cement
(P < 0.001). The glass–ionomer cement did not show a
progressive water uptake or loss with time with the
peak water absorption being at 7 days of curing. The
CSA cement and composite were quite stable and both
lost minimal amounts of water when cured at 100%
humidity (P > 0.05). Both the CFA cement and com-
posite exhibited extensive water loss at all ages.
Discussion
Compressive strength testing of dental cements is usually
performed according to British Standard Institution
(2003). In a previous paper (Camilleri et al. 2006)
testing various proprietary brands, it was concluded that
compressive strength testing depends on specific test
conditions. The cements were not susceptible to changes
in the compressive strength testing procedure at 1 and
7 days, but at 28 days all the fast setting cements had a
significantly higher strength with a particular testing
mode. Abnormal failure occurred when testing accord-
ing to British Standard Institution (2003) and the
standard deviations for the tests carried out were large.
Compressive strength testing of prototype dental
cements was thus performed according to British
Standard Institution (2005a).
The setting time of the cement was controlled by
addition of calcium aluminate. The gypsum present in
the Portland cement system reacts with the calcium
aluminate to produce ettringite as the main by-product
of the hydration reaction. Once the gypsum is depleted,
the calcium silicate hydration reaction is accelerated.
This has already been investigated in a previous paper
(Camilleri et al. 2006) where Portland cement was
admixed with calcium aluminate cement; This resulted
in poor compressive strengths. In the present experi-
ment, excess sulphate ions provided by the synthetic
anhydrite reacted with the calcium hydroxide produced
Table 2 Results of preliminary tests carried out on (a)
granite ± SD; (b) cements ± SD
Test Result
(a)
Relative density kg m)3
2.68 ± 0.56
Loose bulk density g ml)1
1.11 ± 0.1
Moisture content % 0.02 ± 0.01
Water absorption % 1.4 ± 0.19
Test
Cement type
CSA CFA OPC
(b)
Relative density kg m)3
2.95 ± 0.08 2.85 ± 0.04 2.94 ± 0.01
Moisture content % 0.08 ± 0.06 0.06 ± 0.01 0.54 ± 0.05
Fineness m2
kg)1
450 450 421 ± 0.9
The fineness of the CSA and CFA was determined by the
manufacturer.
Table 3 Percentage ratio of materials used in the mix design
Cement type % cement % granite % water % admixture
CSA 100 0 25.00 0.5
CFA 100 0 25.00 0.5
CSAG 58.25 41.60 15.19 0.5
CFAG 58.64 41.36 15.28 0.5
MTA modification Camilleri
International Endodontic Journal, 41, 843–849, 2008 ª 2008 International Endodontic Journal846
5. by the hydration of the tricalcium silicate that increased
the ettringite deposition and resulted in an increase in
initial strength (Kno¨fel & Wang 1993). Strength
development seemed to show a maximum within the
first few days. A qualitative explanation of this behaviour
is based on a combined process of expansive cracking and
0
2
4
6
8
10
12
14
16
18
CFAGCSAGCFACSA
Cement type
FlexuralstrengthNmm-2
1 day
7 days
28 days
56 days
0
20
40
60
80
100
120
140
CFAGCSAGCFACSA
Cement type
CompressivestrengthNmm-2
1 day
7 days
28 days
56 days
(a)
(b)
Figure 1 (a) Mean flexural strength testing of cements and cement composites over a period of 56 days ± SD (n = 6). (b) Mean
compressive strength testing of cements and cement composites over a period of 56 days ± SD (n = 12).
Table 4 Percentage water absorption/shrinkage of cements cured at 100% humidity or immersed in water over a period of
56 days ± SD (n = 6)
Cement type
%water absorption of cements cured in water
at 37 °C/days
%water absorption of cements cured at 37 °C and
100% humidity/days
1 7 28 56 1 7 28 56
CSA 4.16 ± 0.6 4.81 ± 0.5 5.60 ± 0.6 5.90 ± 0.8 )0.80 ± 0.1 )1.09 ± 0.1 )1.62 ± 0.2 )1.97 ± 0.3
CSAG 0.99 ± 0.1 1.29 ± 0.1 2.17 ± 0.1 2.72 ± 0.1 )0.63 ± 0.2 )1.14 ± 0.1 )1.21 ± 0.1 )1.37 ± 0.2
CFA 5.61 ± 0.3 7.57 ± 0.3 7.76 ± 0.2 8.32 ± 0.2 )7.27 ± 0.5 )7.37 ± 0.6 )6.64 ± 0.8 )6.43 ± 0.8
CFAG 2.22 ± 0.6 3.23 ± 0.8 3.22 ± 0.7 3.57 ± 0.7 )5.10 ± 0.2 )5.14 ± 0.1 )4.83 ± 0.2 )4.81 ± 0.2
GIC 1.32 ± 0.0 5.05 ± 2.1 2.92 ± 0.1 3.32 ± 0.2 )2.17 ± 0.3 )3.36 ± 0.4 )3.19 ± 0.4 )3.87 ± 0.5
Camilleri MTA modification
ª 2008 International Endodontic Journal International Endodontic Journal, 41, 843–849, 2008 847
6. self-healing, the balance of which appears to determine
the course of expansion and strength development
(Bentur et al. 1975). The extent of ettringite-related
expansion depends on the conditions of curing. It
increases with increasing amounts of water taken up
from the environment while ettringite is formed, indi-
cating the participation of swelling phenomena in the
expansion process (Odler & Cola´n-Subauste 1999).
Curing in water enhances early ettringite formation
and increase in strength. The fluoro-aluminate cement
contains sufficient tricalcium silicate to achieve high
early strengths (Costa et al. 2000). Utilization of calcium
fluoro-aluminate leads to slow ettringite formation,
which could explain the low compressive strength as
compared with the sulpho-aluminate cement.
Attempts at improving the material strength were
made by using a superplacticizing admixture and by
addition of inert filler. The superplasticizing admixture
causes particle dispersion and allows workability at low
water/cement ratios. Maximum particle packing is
attained by dispersion of the cement grains at low
water/cement ratios with the use of high levels of a
dispersing agent. There is a practical limit to the
reduction of water/cement ratio as the mixture would
become unworkable. The flocculated nature of the
cement particles does not permit fluid suspensions
unless they are dilute (Malhotra et al. 1978). In
addition, the cement was mixed with an inert material
of different particle size in an attempt to improve its
flexural strength. In a particle admixture macroscopic
porosity remains as a result of air entrainment and
defective particle packing. To attain the ideal structure
of strong cement paste, maximum particle packing with
minimal total porosity and elimination of macroscopic
voids is necessary. The use of cement on its own to
produce any kind of material is difficult because of
development of microcracks. The addition of an aggre-
gate is thus mandatory. The strength of a composite
material is influenced by the ratio of cement to mixing
water, the ratio of cement to aggregate, the grading,
surface texture, shape, strength, and stiffness of aggre-
gate particles, and the maximum size of the aggregate
(Gilkey 1961). The Theory of Particle Admixtures
(Dewar 1999) utilizes parameters calculated by phys-
ical tests carried out on the raw materials to calculate
the percentages of materials required to produce
optimal particle packing for maximum strength.
Glass–ionomer cements exhibited hygroscopic
expansion on immersion in water. This expansion
reached its peak after 7 days immersion. Both proto-
type cements showed higher water absorption than
glass–ionomer cement. Addition of granite to the
cements reduced the water exchange within the
material. Both calcium sulpho-aluminate cement and
its composite lost less water when cured at 100%
humidity than glass–ionomer cement. The results
obtained for the prototype dental cements are compa-
rable with those of proprietary brand glass–ionomer
cement (McCabe et al. 1990, Pereira et al. 2002,
Piwowarczyk et al. 2002).
Conclusions
The CSA and CFA cements had adequate setting times
and compressive strength values when compared with
proprietary brand glass–ionomer cement. CSA was
superior to CFA and had more promise as a prospective
dental material. The improved properties of the modified
cement could allow for a reduction in the chair-side time
and amount of visits per treatment when the cement is
used for apexification procedures and pulpotomies, and
enable the material to withstand packing pressures of
restorative materials if used as a pulp capping agent.
Acknowledgements
The University of Malta for funding. Dr J. Newman of
the Department of Civil and Environmental Engineer-
ing, Imperial College London for his help with the mix
design, Mr Gavin Gartshore at Lafarge Special Cements
section, Nottingham, UK and Dr Umberto Costa of
Italcementi SPA, Italy for providing the cement sam-
ples, Mr Roy Jones of Degussa Construction Chemicals,
Manchester, UK for providing the admixture and 3M
Healthcare Limited, Leicestershire, UK for providing the
glass–ionomer cement. Mr Nicholas Azzopardi for his
help with the laboratory work.
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