Optimizing Concrete Pavement Type Selection Based on Aggregate Availability
Record Type: DOT
Coarse aggregate occupies about 40 percent of Portland cement concrete (PCC) volume, and thus has substantial effect on PCC properties, such as coefficient of thermal expansion (CoTE), modulus of elasticity, and drying shrinkage. On the other hand, its effect on strength is not as significant. Effort was made to incorporate PCC properties as affected by coarse aggregate type in rigid pavement designs, most recently in NCHRP 1-37(A), in the development of mechanistic-empirical pavement design guide (MEPDG). However, the approach was limited to the effect of coarse aggregate type on required slab thickness. According to the FY 2010 Texas Department of Transportation Pavement Management Information System (TxDOT PMIS), TxDOT has 12,345 lane miles of continuously reinforced concrete pavement (CRCP) and 1,399 punchouts. All the distresses recorded as punchouts in the Amarillo, Childress, Dallas, Fort Worth, Lubbock, and Wichita Falls districts were visually investigated under TxDOT rigid pavement database project (0-6274). The findings indicated that one-third of the distresses recorded as punchouts in PMIS were actually large spalling and distresses caused by delaminations. They were not due to the structural deficiency of the pavement system. In Texas, spalling and delaminations normally develop in CRCP when certain coarse aggregate types are used. TxDOT recognized this, and sponsored several research studies since the mid-1980s to address this issue, with no solutions obtained. On the other hand, these coarse aggregate types have been used in plain jointed concrete pavement -- called concrete pavement contraction design (CPCD) -- in Texas, with almost no spalling issues. The fundamental design concepts and structural behaviors of CRCP and CPCD are vastly different, and these coarse aggregate types are not compatible with CRCP behavior, resulting in spalling and delaminations. On the other hand, they are quite compatible with CPCD behavior; and the performance of CPCD with those aggregates has been satisfactory. Proper selection of PCC pavement type, based on coarse aggregate type, will enhance overall PCC pavement performance, thus minimizing maintenance and repair costs.
Start date: 2011/9/14
End date: 2012/8/31
Status: Active
Contract/Grant Number: 0-6681
Total Dollars: 170000
Source Organization: Texas Department of Transportation
Date Added: 05/04/2012
Index Terms: Concrete pavements, Pavement type selection, Concrete aggregates, Portland cement concrete, Properties of materials, Paving, Spalling, Delamination, Mix design, Texas Department of Transportation,
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