Response of instrumented concrete pavement slabs to vehicular loads

Jointed plain concrete pavements are designed on the basis of edge stresses developed at the bottom of the slab, under environmental and vehicular loads. Various parameters related to material, traffic, environment and surrounding conditions of the pavement slab influence these stresses. This paper presents the effect of tie bars, aggregate interlocking, interface friction and lateral placement of wheel load on edge load stresses. An instrumented concrete pavement section with a dry lean concrete base layer was constructed and load tests were conducted. The test results indicated a significant reduction in edge load strains due to tie bars and aggregate interlocking at saw-cut longitudinal joints. An average load transfer efficiency of 60% was achieved at tied saw cut joints. The friction at the interface of concrete slab and underlying dry lean concrete base layer also considerably reduced the bottom tensile strains. Extra-widening of the slab by a minimum of 250 mm or providing a tied concrete shoulder showed an equivalent effect in reducing the bottom edge strains.