Thermal Stresses of PCC Pavements Containing Fly Ash and Slag

Abstract

With the current demand for portland cement concrete (PCC) sustainability, supplementary cementitious materials (SCMs) are often used in concrete mixtures to improve the mixture properties in both fresh and hardened concrete. In this research, sixteen concrete mixtures (one control mixture, three binary mixtures, and twelve ternary mixtures) with various combinations of fly ash, slag, and portland cement were fabricated. The thermal and mechanical properties of the selected ternary mixtures were measured at various ages, and the critical temperature gradient through the slab thickness was generated by using the enhanced integrated climatic model (EICM). By using the measured mechanical properties, nonlinear temperature gradients obtained from EICM, and CTE gradients throughout the slab thickness, Westergaard-Bradbury solution was used to calculate the critical tensile stress on the PCC pavements. The analysis results show that all the ternary mixtures with the replacement of 30% slag and 30% fly ash, and replacement of 50% slag and 20% fly ash did not exceed 100% tensile stress-to-strength ratio at all ages.