Internally Cured Concrete for Pavement and Bridge Deck Applications

Laboratory and full-scale slab testing programs were conducted to evaluate the performance of internally cured concrete (ICC) using lightweight aggregates for application in bridge decks and concrete pavement. The laboratory testing program evaluated three standard mixes (SM) and three ICC mixes with the same water-to-cementitious materials (w/cm) ratio and cementitious content. The amounts of water-reducing admixtures needed for the ICC mixes to achieve the same workability was less than that needed for the corresponding standard mixes. The compressive strength, flexural strength, elastic modulus, splitting tensile strength, and coefficient of thermal expansion of the ICC mixes were lower than those of the SM mixes with the same w/cm ratio. Restrained shrinkage testing indicated that the ICC mixes, despite having higher drying shrinkage, had a substantially greater resistance to shrinkage cracking than the standard mixes. One SM and two ICC test slabs were constructed to evaluate the performance of ICC in pavement slabs. The results of the critical stress analysis from finite element models show that, at a critical loading condition, the computed stress-to-strength ratios for the ICC slabs were lower than those of the SM slab. Heavy vehicle simulator (HVS) testing of the SM slab produced some hairline cracks next to the wheel path. These hairline cracks possibly occurred when microshrinkage cracks developed into hairline cracks after the slab was loaded repetitively by the HVS. No surface cracks were observed for the two ICC slabs after HVS testing. Based on these results, the ICC test slabs had higher resistance to cracking than the SM test slab.