Effects of Modulus of Rupture of Concrete on Performance of Unbonded Jointed Plain Concrete Overlay

Abstract

Rehabilitation of existing jointed plain concrete pavements (JPCP) by using unbonded concrete overlay (UBCO) is increasingly being used all over the world. The design and performance of un-bonded overlays is affected by various factors including climate, traffic volume, concrete material properties, existing pavement condition and future design life. Modulus of rupture (MOR)/flexural strength of concrete is an important material property that has significant impact on the performance of concrete pavements. A true estimation of modulus of rupture would improve the accuracy of cracking prediction. This study examines the impact of variability of flexural strength of concrete on the mechanistic-empirical performance predictions of UBCOs. Simulations were conducted using pavement ME design software with varying flexural strength values and keeping all other design variables as constant. The results indicated that MOR has a significant impact on overlay performance. With decrease in concrete’s MOR, the performance of UBCOs is adversely affected with increased transverse cracking. The adverse effects of lower flexural strength can be compensated by increasing the thickness of overlay concrete slab or by decreasing the transverse joint spacing.