Two-Lift Paving - Project Background, Tasks, and Findings
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Two-Lift Paving - Project Background, Tasks, and Findings

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A Two-Lift concrete Paving (2LCP) workshop was organized as a part of the Texas Department of Transportation (TxDOT) project 0-6749: Feasibility Study of Two-Lift Concrete Paving (2LCP). This workshop ...

A Two-Lift concrete Paving (2LCP) workshop was organized as a part of the Texas Department of Transportation (TxDOT) project 0-6749: Feasibility Study of Two-Lift Concrete Paving (2LCP). This workshop was conducted at the J. J. Pickle Research Campus (PRC), The University of Texas at Austin, Austin, TX on May 23rd, 2013. Dr. Jiong Hu, Texas State University, Research Supervisor, and Dr. David Fowler, The University of Texas at Austin, Co-Research Supervisor, co-chaired the workshop. The workshop offered the option of attending in person or remotely through webinar. Fifty-one attendees were present remotely or in person; 28 in person and 23 persons remotely.

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Two-Lift Paving - Project Background, Tasks, and Findings Two-Lift Paving - Project Background, Tasks, and Findings Presentation Transcript

  • Two-Lift Concrete Paving Workshop 5/23/2013 Texas State University & University of Texas at Austin
  • Welcome and opening comments Mr. Darrin Jensen Dr. Jiong Hu 2
  • Self introduction of attendees 3
  • Background of project: Why two-lift paving? Dr. David Fowler 4
  • What is two-lift paving?  Placing two layers of concrete, wet on wet, rather than the usual single lift of concrete.  Bottom layer is much thicker, e.g. 8 or 9 in, and the top layer is much thinner, e.g. 2 or 3 in.  Bottom layer can contain aggregates that are not suitable for top layer.  Top layer contains better quality aggregates 5
  • Major benefits 1. Permits concrete with lower unit cost to be used for lower layer  significant amounts of local materials including aggregates that are inappropriate for surface courses including recycled and high CTE coarse aggregates and carbonate fine aggregates which reduces transportation  Lower cement contents  Higher amounts of supplementary cementitious materials 6
  • 2. More efficient and economical use of specialized mixtures to produce desirable surface characteristics for top layer  Improved skid resistance  Reduced noise  Improved durability 7
  • Importance to TxDOT  Some areas including Dallas and Fort Worth are faced with depleting sources of quality natural silica sands.  The carbonate manufactured sands make good concrete but are not suitable for concrete pavement surfaces due to polishing.  Fine aggregates have the greatest influence on skid resistance in concrete pavements.  Softer carbonate fines tend to polish faster than harder silica aggregates 8
  • Skid Resistance – Aggregate Test  The test adapted by most highway state agencies is the acid insoluble residue test (AI).  It was originally 28% in Texas and effectively omitted all carbonate fine aggregates.  When the specifications were rewritten in 1993, the limit was set at 60% because that was representative of the value used by the districts. 99
  • Skid Resistance – AI Test The minimum acid insoluble residue limit in Texas was originally 28%. This limit effectively omitted all carbonate fine aggregates. Between 1982 and 1993, some districts had started using higher requirements by plan note. When the specifications were rewritten in 1993, the limit was set at 60% because that was representative of the value used by the districts. 1010
  • Skid Resistance – Fine Aggregates 11 Hard siliceous FA Original Section Abraded Section Soft limestone FA Texture created by finishing technique 11
  • High Microfine (aggregates passing #200) MFA Implementation Project Sect 1 – 5% Sect 2 – 10% Sect 4 – Optimized Sect 3 – 15% 1212
  • Section 1 – 5% Microfine Addition (Right lane) On Wheel Paths Between Wheel Paths 1313
  • Skid Resistance - Concrete 14 Locked-Wheel Skid Trailer Dynamic Friction Tester (DFT)14
  • DFT60 vs. SN(50)smooth Measured (concrete: carpet drag + tined) 1515
  • Field Sections – Blended vs. 100% MFA 1616
  • Friction Results at 160,000 Cycles for Blended Sands 17 17
  • What is the implication for two-lift paving?  100% carbonate fine aggregates can’t be used.  Blending may permit up to 60% carbonate fines in top lift and 100% in bottom lift. 18
  • Reduction in amount of natural sand  For single lift 100% natural sands = 100% N.S.  For two lift, 10” bottom lift and 2”  top lift using 100% natural sand  = 2/12 x 100 = 16.7% N.S.  For two lift with 40% N.S. and 60%  MFA for 2” top lift = 0.4 x 16.7 = 6.7% N.S. 19
  • What we hope to learn  Under what conditions is two-lift paving appropriate for Texas?  This involves many factors:  Economics  Materials  Equipment  Construction  Specifications 20
  • Project Tasks Dr. Jiong Hu 21
  • Project Tasks Project 0-6749: Feasibility Study of Two-lift Concrete Paving  Task 1 Literature survey of past experience of 2LCP  Task 2 Evaluation of the state-of-the-practice of 2LCP  Task 3 Summary of construction perspectives of implementation of 2LCP  Task 4 Cost effectiveness analysis and best practice of 2LCP 22
  • Task 1 Literature survey of past experience of 2LCP 23 Task 1.1 Summary of previous experiences and past performance of 2LCP Task 1.2 Summary of potential benefits, challenges and cost effectiveness of 2LCP
  • Task 1.1 Summary of previous experiences and past performance of 2LCP 24 Year Country /State Highway/Location EAC? Length (mi.) Traffic (ADT) References EuropeanExperience 1989 Austria Freeway A1 Y NA (Tompkins 2009) (SHRP2) 1994 Austria A1 near Eugendorf Y NA 56,000 (Tompkins 2009) (SHRP2) 1994 Austria A1 near Traun Y NA 55,000 (Tompkins 2009) (SHRP2) 1999 Austria A1 nearVorchdorf Y NA 56,000 (Tompkins 2009) (SHRP2) 2003 Belgium N511 at Estaimpuis* Y 0.8 2,000 (Debroux 2005) 2005 Belgium E34 motorway in Zwijndrecht * 1.9 (Rens 2008) 2008 Germany A6 Near Amberg Y 13 80,000 (Tompkins 2009) (SHRP2) NA France Highway A71 NA (Cable 2004) NA Germany Munich Airport NA (Cable 2004) USExperience 1976 Iowa US 75 NA (Bilec 2010) 1976 North Dakota US 2 b/w Rugby and Leeds NA (Bilec 2010) 1977 Florida US 41 2.5 (Bilec 2010) (Cable 2004) 1994 Michigan I-75, NB Y 1 (Smiley 2010) (Bilec 2010) 1997 Kansas NA Y 0.7 (Cable 2004) (Wojakowski 1998) 0.4 0.8 2008 Kansas I-70 in Saline County Y 5 (Fick 2009) (CP Road Map 2010) 2008 Pennsylvania Mon-Fayette Expressway NA (Bilec 2010) 2010 Minnesota I-94, Cell 71 Y NA 27,500 (Akkari 2011) (Tompkins 2011)I-94, Cell 72 Y NA 27,500 2012 Illinois Tollway 4.2 (Gillen 2012) Avg 3.03 43,429 *CRCP section
  • Task 1.1 Summary of previous experiences and past performance of 2LCP 25 Year Country /State Highway/Location Bottom Lift Thicknes s (in.) Aggregate Slump (in.) Air (%) Strength (psi) EuropeanExperience 1989 Austria Freeway A1 8.5 RCA and RAP 1994 Austria A1 near Eugendorf 8.3 RCA, MSA 1.26" 1994 Austria A1 near Traun 7.9 RCA, MSA 1.26" 1999 Austria A1 nearVorchdorf 8.3 RCA, MSA 1.26" 2003 Belgium N511 at Estaimpuis* 6 Porphyry 0.59 5 2005 Belgium E34 motorway in Zwijndrecht * 7 Broken stone, max 60% RCA 2008 Germany A6 Near Amberg 10 River gravel NA France Highway A71 NA Local limestone NA Germany Munich Airport 9.5 Local gravel USExperience 1976 Iowa US 75 9 60% RCA, 40% RAP 1976 North Dakota US 2 b/w Rugby and Leeds 6 NA 1977 Florida US 41 9 Limestone 1994 Michigan I-75, NB 7.5 Dolomitic limestone 5000 1997 Kansas NA 7 15% RAP 7 High abs. limestone 7 Limestone & pea gravel 2008 Kansas I-70 in Saline County 11.8 Limestone 1.3 7 2008 Pennsylvania Mon-Fayette Expressway 8 NA 2010 Minnesota I-94, Cell 71 6 50% RCA, 1 I-94, Cell 72 6 Relaxed agg. Grad. 1 2012 Illinois Tollway 8 RAP& CM-11 Limestone 3 6.5 3500 Avg 7.9 1.4 6.2 4250
  • Task 1.1 Summary of previous experiences and past performance of 2LCP 26 Year Country /State Highway/Location Top Lift Thickne ss (in.) Aggregate Slump (in.) Air (%) Strengt h (psi) EuropeanExperience 1989 Austria Freeway A1 1.6 Harder aggregate 1994 Austria A1 near Eugendorf 1.6 Diabase aggregate, MSA 0.31" 1994 Austria A1 near Traun 2 Diabase aggregate, MSA 0.43" 1999 Austria A1 nearVorchdorf 2 Diabase aggregate, MSA 0.43" 2003 Belgium N511 at Estaimpuis* 2 Porphyry 1.2 4 2005 Belgium E34 motorway in Zwijndrecht * 2 Broken stone, with polishing resistance requirement 2008 Germany A6 Near Amberg 2 Crushed granite, gap-graded, MSA 0.31" NA France Highway A71 2 Harder aggregates NA Germany Munich Airport 5.5 Crushed granite USExperience 1976 Iowa US 75 4 All virgin materials 1976 North Dakota US 2 b/w Rugby and Leeds 3 Crushed rock and sand 1977 Florida US 41 3 Limestone 1994 Michigan I-75, NB 2.5 Ontario trap rock (crushed basalt) 5500 1997 Kansas NA 3 Limestone 3 Rhyolite 3 Limestone & pea gravel 2008 Kansas I-70 in Saline County 1.6 Rhyolite 1.9 7.5 2008 Pennsylvania Mon-Fayette Expressway 4 NA 2010 Minnesota I-94, Cell 71 3 ½” and 3/8” W. Chips Granite 1 5600 I-94, Cell 72 3 ½” W. Chips and 3/8” W. Chips 1 5600 2012 Illinois Tollway 3.5 CM-11 Limestone 3 6.5 3500 Avg 2.7 1.62 6 5050
  • Task 1.2 Summary of potential benefits, challenges and cost effectiveness of 2LCP 27 Additional requirements for 2LCP  Time lag between lifts (up to 30 mins/ 30-60 mins)  Additional mixing plants (drums), paving machines, belt placer and extra trucks.  Additional crew members and better trained workforce  Well organized jobsite and scheduling of operating additional equipment  Bottom lift concrete was placed with spreader, spreader box, Rex Belt placer, or two belt spreader.Top lift was placed with slip-form paver in every project.
  • Task 1.2 Summary of potential benefits, challenges and cost effectiveness of 2LCP  Benefits of using 2LCP - Use low quality materials in bottom layer and high quality materials in top layer.  Locally available low quality/high polish materials can be used in bottom lift. Recycled material can be used.  Top lift is relatively thinner and less high quality aggregate needed; makes it an economical choice.  Challenges of using 2LCP  Required additional equipment and construction requirements, including a second paver, second batch plant etc.  Construction scheduling and planning is also considered as a major challenge to adoption of the 2LCP concept in the United States.  While experiences in Europe shows comparable cost (of 2LCP comparing to traditional one lift paving), for these experimental projects the cost of 2LCP was twice than the conventional concrete pavement. 28
  • Task 2: Evaluation of the State-of-the- Practice of 2LCP Task 2.1 Surveys and interviews of contractors and agencies with experience in use of 2LCP. Task 2.2 Surveys and interviews of contractors and TxDOT personnel regarding concerns with 2LCP Task 2.3 2LCP workshop 29
  • Task 3 Summary of construction perspectives of implementation of 2LCP 30 Properties of each lift  Material requirements, thickness of two lifts, slump, air content, set time and permeability Minimum requirements of material  Aggregate gradation, recycled aggregate limits, admixture requirements, compressive strength, modulus of rupture and durability Surface characteristics  Type of aggregate, skid resistance, friction, noise and splash
  • Task 3 Summary of construction perspectives of implementation of 2LCP 31 Additional equipment, construction, and scheduling requirements  a second paving machine  a second batch plant (or second mixer and additional aggregate bins)  a second belt placer/spreader (in place of a second paving machine)  extra hauling and extra labor for hauling and running the second batch plant (mixer) and placer/spreader
  • Task 3 Summary of construction perspectives of implementation of 2LCP 32  Concerns of Implementation of 2LCP  Extra permits and land space for two paving plants  Well organized jobsite and scheduling of operating additional mixing plant, paving machines and trucks  Clear definition of “stiff” of bottom lift  Pavement vibration system to minimize potential for segregation  Minimum thickness of the top lift  Maximum/optimum time lag to eliminate potential debonding (In K-96 project minimum waiting time of 30 minutes was necessary to prevent mixing of the two lifts. In the same project, low w/c concrete was used in top lift without any debonding problem)  Durability (In Florida 23 sections out of 33 sections are still in service.The other ten sections were removed within 2 years of service. )
  • Task 4 Cost effectiveness analysis and best practice of 2LCP Task 4.1 Cost effectiveness of 2LCP Task 4.2 Feasibility study of the most promising practice of 2LCP 33
  • Task 4.1 Cost effectiveness of 2LCP 34 Changes (increases) of labor and equipment costs between two-lift pavements and traditional single lift pavements need to be quantified to effectively determine if material and/or life-cycle costs can offset the additional costs on a project specific basis. Research team will work with PM & PMC to develop case studies of potential cost benefit (both construction cost and life cycle cost) in selected districts facing aggregate shortages to justify cost effectiveness. Also included, will be an analysis of potential economic benefits of surface improvements.
  • Task 4.1 Cost effectiveness of 2LCP 35 Type of Pavement Thickness Cost of Materials (CY) Pavement Cost-in- Place (CY) Cost of Pavement (SY) Standard Mix 12” $57 $99 $33 Durable Mix 12” $102 $144 $48 Two- Lift Bottom-Lift 10” $57 $108 $30 Surface Lift 2” $102 $190 $11 Identifies $/SY of 2LCP to be $8 more than a standard mix and $7 lower than a durable mix. (Hoard 2009) Case Study - Kansas I-70 2008
  • Task 4.1 Cost effectiveness of 2LCP Rao S., Darter M.I., Composite Pavement Systems – A Sustainable Approach for Long-Lasting Concrete Pavements, 10th International Conference on Concrete Pavements, 2012. Case Study - MnRoad SHRP2 2010 36
  • Task 4.1 Cost effectiveness of 2LCP Krummen S., Constructing a Composite Pavement from Subgrade Up, 91st AnnualTRB Meeting, January 22, 2012. Case Study - MnRoad SHRP2 2010 Conventional Concrete Composite Concrete Mix Production $5,501,000 $4,850,000 Pavement Placement $809,000 $1,325,000 Total Pavement Cost $6,310,000 $6,175,000 Unit Cost $20.38/sy $19.94/sy $135,000 Net Cost Advantage $0.44/cy less (2% Discount) 37
  • Task 4.1 Cost effectiveness of 2LCP 38 One-Lift Paving (Local Agg.) One-Lift Paving (Imported Agg.) Two-Lift Paving Material Costs Top Lift -   Bottom Lift NA NA  Constructi on Costs Mixing Plants - -  Pavers - -  Extra Equipment - -  Extra Labor - -  Current Costs ?() ? () ? () Maintenance Costs   ?() LCC ? ? ?
  • Task 4.2 Feasibility study of the most promising practice of 2LCP  Research team will provideTxDOT with a recommended best practice protocol for implementing and managing a cost effected 2LCP project. 39
  • Findings from Tasks 2 Mr. Michael Grams (Texas State University) Mr. Md Sarwar Siddiqui (CTR, University of Texas) 40
  • Task 2.1 Surveys and interviews of contractors and agencies experience with 2LCP Mr. Michael Grams (Texas State University) 41
  • Task 2: Evaluation of the State-of-the- Practice of 2LCP Task 2.1 Surveys and interviews of contractors and agencies with experience in use of 2LCP. Task 2.2 Surveys and interviews of contractors and TxDOT personnel regarding concerns with 2LCP Task 2.3 2LCP workshop 42
  • Task 2.1 Surveys and interviews of contractors and agencies experience with 2LCP A detailed sixteen question survey was issued through Survey Monkey to both domestic and European contractors, suppliers, researchers, and Department of Transportation personnel who were identified through a literature review as having experience with 2LCP. The survey was divided into 5 categories that covered: general information of the respondent, mix design and material properties, construction, cost, and overall experience of 2LCP. Over 100 invitations were sent out. A total of 26 individuals responded and took the survey, including 9 through phone interviews. 43
  • Task 2.1 Personnel Participated Surveys 44 Name Affrications Project Peter Schöller Österreichische Betondecken Arge Europe Ronald Blab Vienna University of Technology Austria, Germany and Slowenia Luc Rens FEBELCEM - EUPAVE Belgium Thomas Sorel MnDOT MnROAD Thomas Kazmierowski Ontario Ministry of Transportation Highway 407,Toronto José Tadeu BALBO USP NA ArjanVenmans provincie Noord-Brabant The Netherlands Veghel,The Netherlands, secondary road N279 Jussara Tanesi FHWA-TFHRC-HRDI Aggregate/Petrographic Lab (APL) Kansas I-70 Ben Worel Minnesota Department of Transportation MnROAD (Interstate - 94) James Crites Parsons Corp (on behalf of DFW Airport) NA Richard Abell Highways Agency Kessignland, Suffolk Mark B Snyder ACPA - PA Chapter Pennsylvania Turnpike - Mon-Fayette Expwy Mark Watson Minnesota Department of Transportation MnROAD I-94 Suneel N.Vanikar FHWA Several demonstration projects in USA Denis Thebeau Ministere des transports du Quebec Hwy 15 Mirabel Northboun Quebec Canada John Donegan Aggregate Industries UK A449 - South Wales, UK Alfred Weninger-Vycudil PMS-Consult GmbH, Naglergasse 7,Vienna,Austria Austria and Germany Steven Gillen Illinois Tollway I-88 Illinois Tollway Robert Rasmussen Transtec I-70, Europe Jim Grove FHWA Kansas I-70 Tom Cackler CP Tech Kansas I-70 James Cable Cable Construction NA Gary Fick Trinity Construction Kansas I-70 Tim Gerhardt Koss Construction Kansas I-70 Ron Meskis Gunter & Zimmerman NA
  • Task 2.1 Surveys and interviews of contractors and agencies experience with 2LCP 45
  • Task 2.1 Survey – General Information 46  Question2: How many years do you have with paving experience?  Question3: Which of the following best describe your field of experience in paving? Results from 25 valid responses Results from 25 valid responses 4% 0% 8% 88% 0 to 5 6 to 10 11 to 15 Over16 24% 32% 40% 4% Design Construction Research Equipment
  • Task 2.1 Survey A – General Information/Cost 47  Question5: Major reason for using 2LCP vs. traditional paving?? Results from 22 valid responses  Question11:Which of the following attributed to the greatest impact to overall 2LCP project cost? Results from 19 valid responses 6% 28% 13% 44% 9% Agg. Availability Surface Char. Economic Experimentation Others 0% 66% 3% 8% 13% 10% Extra Supervision Extra Equipment Extra Manpower Unexpected Expenditures Preplanning Others
  • Task 2.1 – General Information/Mix Design & Materials Properties 48 Lane Mile ADT Top LiftThickness Bottom LiftThickness Count 8 7 11 10 Max 7450 140000 6.0 8.3 Min 0.19 4000 1.6 6.0 Avg 954 47214 3.0 6.9 Stdev 2625 45170 1.2 1.0 AggregateType Top – Coarse Aggregate Basalt rocks and diabase rocks, Porphyry, Dolomitic sandstone, Granite, Flint gravel, whinstone, limestone Top – Fine Aggregate River sand, manufacture sand, natural sand Bottom – Coarse Aggregate Old pavement, RCA, Porphyry - Limestone - Recycled concrete , Flint Gravel Bottom – Fine Aggregate River sand, natural sand
  • Task 2.1 Survey A – Construction 49  Question 9: Please rate the following aspects of 2LCP vs. traditional paving methods  Question10: Please identify the way(s) that challenges of 2LCP were overcome most. Results from 22 valid responses Results from 24 valid responses 13% 0% 73% 14% Extra Supervision Unexpected Expenditures Preplanning Others 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Scheduling Additional equipment Aggregate selection Mixing Placing Consolidation Curing QA/AC 5=substaintial 4 3=extra effort required 2 1=the same
  • Task 2.1 Survey A – Overall Experience 50  Question12: On a scale of 1-5 (1=worse and 5=best), please rate your overall experience with 2LCP  Question13:Would you like to participate on another 2LCP project? Results from 22 valid responsesResults from 22 valid responses 0% 0% 41% 45% 14% 1=worse 2 3 4 5=best 91% 9% Yes No
  • Task 2.1 Survey A – Overall Experience 51  Question14: On a scale of 1-5 (1=immediate need and 5 = no need at all), please rate your opinion on need for a 2LCP at this time  Question15: If you chose there is not a need for 2LCP at this time, when do you think there will be a need? Results from 11 valid responsesResults from 22 valid responses 9% 14% 36% 23% 18% 1=immediate need 2 3 4 5=no need at all 37% 27% 18% 9% 9% In 1 to 2 years In 3 to 5 years In 6 to 10 years In 11 to 20 years More than 30 years
  • Task 2.1 Survey A - Comments regarding needs for 2LCP 52 Comments Pros  With the 2LCP it is possible to create a higher-quality concrete surfaces and the opportunity to recycle old concrete pavements.With the two layer you can use different consistencies between the upper and lower concrete. In Austria, we are convinced of this 2LCP method since decades.  Higher priority needs at this time, but technology has technique has interest due to potential for sustainability benefits.  Better utilization of local aggregates or recycled aggregates; friction; reduced noise. Decrease in supply of high quality aggregate and higher transportation (trucking) costs  Desirable to ensure most economic use of aggregate  Contractor unable to achieve required ride quality with single layer  Depends on location and aggregate availability - its something new that must also be accepted as an option  Choice is ultimately left to the owner  Main reason is reduced noise level of fine exposed aggregate concrete. However, comparable noise levels have recently been met with a single layer concept of exposed aggregate concrete. So, the question is if it is worth facing the extra efforts and risks. Cons  XXX is fortunate to have very good quality aggregate available across most of the state. We have not felt the need for 2LCP.  Original reason is traffic noise nowadays we would make a concrete road with a silent asphalt topping  Experience was mainly for skid resistance issue but up to now, we are disappointed even if we used hard aggregates. Need 2 sets of paving machine or special piece of kit. Since resistance asked of 35 MPa is pretty low, powerful brushing equipment for exposed aggregate cannot be used within 24 hrs so we have problems of uniformity of texture.  Method is new and therefore higher bids are received and should be accepted as an option
  • Task 2.2 Surveys and interviews of contractors and TxDOT personnel regarding concerns on 2LCP Mr. Md Sarwar Siddiqui (CTR, University of Texas) 53
  • Task 2.2 Surveys and interviews of contractors and TxDOT personnel regarding concerns on 2LCP  Contact contractors and TxDOT personnel from the larger urban districts and the Construction Division’s Pavements and Materials and Tests for their initial inputs regarding concerns with 2LCP.  Prepare survey for this focused group and summarize those survey and obtain specific information. 54
  • Survey for Potential Two-Lift Paving (2LCP) Users  Target audience is TxDOT personnel and pavement contractors.  Online survey was the primary method of response.  Total of 12 responses were received. 55
  • Survey Responders Distribution 42% 50% 8% Contractors TxDOT Others 56
  • Paving Experience (Years) 8% 38% 0% 54% 0-5 6-10 11-15 Over 16 57
  • Field of Experience in Paving 23% 54% 23% 0% Design Construction Research Equipment Manufacturer/Designer 58
  • Experience with Two Lift Concrete Paving 39% 31% 15% 15% have heard not familiar participate in a project like the opportunity to participate 59
  • Major Issues to Implement 2LCP 90.9% 81.8% 0.0% 18.2% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Constructability Increased cost Maintenance Material compatibility 60
  • Major Concern with 2LCP 53.8% 69.2% 0.0% 23.1% 15.4% 0% 10% 20% 30% 40% 50% 60% 70% 80% Constructability Increased cost Maintenance Material compatibility I do not have any major concerns with 2LCP Responders also selected additional labor and equipment and coordination of two plant batching as other potential concerns.61
  • Degree of Concern of Various Aspects 8% 25% 17% 0% 33% 17% 0% 0% 42% 42% 8% 8% 17% 25% 17% 17% 42% 33% 25% 25% 17% 25% 25% 42% 8% 0% 17% 42% 25% 8% 25% 8% 0% 0% 33% 25% 8% 17% 33% 33% Very Strong Strong Moderate Low None 62
  • Likelihood of Implementing 2LCP 7% 46%31% 8% 8% No Low Moderate Strong Very Strong 63
  • Need of 2LCP 8% 8% 8% 38% 38% No Low Moderate Strong Very Strong 64
  • Summary  More than 50% of the respondents have over 16 years of experience.  Approximately half of the respondents are experienced in construction followed by design and research. No equipment manufacturers participated in the survey.  About 30% of the participants had never heard of 2LCP. About 40% had heard and 15% had participated in 2LCP projects. 65
  • Summary  Constructability and increased cost are the two major concerns in implementing 2LCP.  Most of the survey takers have low to moderate likelihood of implementing 2LCP.  76% of the participants indicated strong to very strong need for 2LCP. 66
  • Invited Presentations 67
  • TxDOT Prospective Mr.Andy Naranjo,TxDOT 68
  • Introduction of two-lift paving Dr. Peter Taylor, CP Tech Center 69
  • Designers’ viewpoints Mr. Luc Rens, EuPave 70
  • Environmental performance Mr. Joep Meijer,The Right Environment 71
  • Agency viewpoints Mr. Shreenath Rao ARA, IL Tollway 72
  • Contractors’ viewpoints Mr.Tim Gerhardt, Koss Construction 73
  • Pavement equipment suppliers Mr. Kevin Klein, Gomaco 74
  • Two-lift paving research Mr.Alex Brand, University of Illinois 75
  • Organized Discussions 76
  • Summary of Major Issues and Findings Dr. David Fowler 77
  • Action Items Dr. Jiong Hu 78
  • Adjourn 79