01026032

Component

Portland cement concrete (PCC) has a positive coefficient of thermal expansion (CTE). The CTE is an important input parameter for the Jointed Plain Concrete Pavement (JPCP) design following the Mechanistic-Empirical Pavement Design Guide (MEPDG) because of its effect on critical PCC slab stresses and also on joint and crack openings. MEPDG suggests the use of PCC CTE input at three hierarchical levels depending upon the efficacy of design – level 1 from actual tests for highest accuracy; level 2 from less than optimal testing or by calculations considering the PCC as a matrix of aggregates and hardened cement paste and knowing their individual CTE’s; and level 3 from agency database or knowledge. The effect of these hierarchical input levels of CTE on the predicted JPCP performance for six in-service pavement sections in Kansas were studied in this paper. The CTE results from the Long Term Pavement Performance (LTPP) projects in Iowa, Kansas, and Missouri were also reviewed. The results show that the range of measured PCC CTE values in Kansas according to the AASHTO TP-60 protocol is quite wide. The calculated PCC CTE value is always higher than the measured value. The effect of PCC CTE input on predicted roughness International Roughness Index (IRI) is more pronounced for JPCP with thinner slab or lower PCC strength. A combination of high cement factor and higher PCC CTE would result in higher JPCP faulting. In general, faulting is very sensitive to this input. PCC CTE also has a very significant effect on slab cracking. However, it does not affect the predicted IRI for a JPCP with widened lane and tied PCC shoulder. Level 2 CTE input may result in more conservative JPCP design than that using Level 1 input. The detrimental effects of high CTE value can be mitigated using higher PCC slab thickness, larger diameter dowel bars or widened lane with tied PCC shoulder. Among these alternatives, the widened lane appears to be the most effective solution since no additional cost is necessary for this strategy.

01020180

06-2573

English

21p

2006

Transportation Research Board 85th Annual Meeting

CD-ROM

Figures (3) ; References (8) ; Tables (6)

Coefficients; Concrete pavements; Mechanistic design; Portland cement concrete; Thermal expansion

International Roughness Index

Coefficient of thermal expansion

Kansas; Missouri

Design; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways

Transportation Research Board Annual Meeting 2006 Paper #06-2573

TRIS, TRB

Mar 3 2006 11:04AM