Paper and Presentation by Moon Won from ASCP 4th Concrete Pavements Conference 2017
As of 2016, there are 21,799 lane kilometres of continuously reinforced concrete pavement (CRCP) managed by the Texas Department of Transportation (TxDOT). CRCP is a premium pavement type, with a higher initial construction cost than jointed plain concrete pavement (JPCP), primarily due to the material and installation cost of steel reinforcement. In Texas, the long-term performance of CRCP has been far superior to that of JPCP. Based on the performance histories of the two Portland cement concrete (PCC) pavement types in Texas, in 2001, TxDOT made it a policy to utilize CRCP when a rigid pavement is selected for projects.
Over the years, CRCPs designed and built in accordance with TxDOT’s design standards and specifications have provided overall excellent performance; however, some premature distresses have been observed in CRCP. Since CRCP is more expensive than JPCP, and is placed where heavy truck traffic volume is high, minimizing premature distresses and thus eliminating the need for lane closures for any maintenance work is of prime importance to TxDOT. To achieve the goal of developing near zero-maintenance CRCP, TxDOT has initiated a number of research studies and forensic evaluations, with a primary goal of identifying the mechanisms of premature distresses and developing design standards and construction/materials specifications that would result in minimizing premature distresses and extending CRCP pavement life.
The major findings from those studies and investigations included; (1) structural distresses in CRCP are rare in Texas where tied-concrete shoulders and stabilized bases were utilized, (2) most, if not all, of the distresses are due to deficiencies in quality control for materials and construction, (3) many of what appear to be full-depth failures are actually partial-depth failures, (4) transverse crack spacing does not appear to have significant effects on longterm performance, (5) concrete properties, especially the coefficient of thermal expansion (CTE), have significant effects on major spalling development, and (6) the use of lower amounts of longitudinal steel than the generally accepted 0.6 % resulted in poor performance.
Based on these findings, TxDOT revised its CRCP design standards in 2013 and construction/material specifications in 2014. The implementation of those design standards and specifications is expected to further enhance long-term CRCP performance in Texas.