The effect of superplasticizer admixture on the engineering characteristics of roller-compacted concrete pavement

Abstract

This study investigates the effect of using different amounts of superplasticizer (SP) (0.25% and 0.50%) on fresh and hardened properties, durability, ultrasonic pulse velocity (UPV) and thermal conductivity of two RCC pavements with cement contents of 12% (269 kg/m3) and 15% (325 kg/m3). The test results demonstrate that the use of 0.50% SP in RCC pavement containing 12% and 15% cement decreased Vebe time about 22% and 27%, respectively. Also, an increase in cement content from 12% to 15% decreased the Vebe time about 18%. With the use of 0.50% SP, the 28–day compressive strength for RCC pavements containing 12% and 15% cement increased by 9% and 14%, respectively. In addition, the use of 0.50 SP reduced the porosity of RCC pavement, to about 8% for RCC pavement with 12% cement and 4% for RCC pavement with 15% cement. The results demonstrated that using 0.5% SP increased the thermal conductivity of RCC pavements containing 12% and 15% cement around 19% and 7%, respectively. Generally, the UPV and Field Emission Scanning Electron Microscope (FESEM) test results showed that the use of SP in RCC pavement may lead to a denser structure.