Studies on Temperature Differential for Different Types of Overlay Over Cement Concrete Pavement

Temperature is an important factor influencing the design and functioning of concrete pavements. The study involves determination of temperature differential in cement concrete slab casted with alternative materials when bituminous overlay is provided. In this study, cement concrete slabs of dimensions of 500 × 500 × 100 mm and 500 × 500 × 200 mm were casted for M40 grade, and an overlay of 40 mm thickness was casted with bituminous concrete (BC), stone matrix asphalt (SMA), open-graded friction course (OGFC) and two-lift concrete having recycled concrete aggregates (RCAs) in lower lift and fly ash with upper lift consisting of virgin aggregates. Temperature was measured at different depths, i.e. surface, mid-depth, bottom for above-mentioned categories. Temperature differential was found to be maximum for BC overlay having maximum positive temperature differential of 11.2° and minimum negative temperature differential of 6.1° in corner region for 100-mm concrete overlay. Similarly, the minimum temperature differential was observed for RCA slab having maximum positive temperature differential of 2.1 at corner and minimum negative temperature differential of 4.4 in edge region in 100-mm concrete overlay. However, it was observed that there was no appreciable temperature differential for SMA, OGFC mixes when compared to BC mix at corner, edge and middle regions.