Experimental Studies on Interface Bond Strength Of ultra thin Whitetopping Pavements under Static and Dynamic Loading Conditions

Abstract

The concrete overlays on existing asphalt pavements are classified into three categories newlinenamely whitetopping, thin-whitetopping and ultra-thin whitetopping (UTW). The newlineinterface bond strength between the existing hot mix asphalt (HMA) pavement and the newlineUTW overlay is the key factor towards the success of UTW overlays. newlineThe aim of the present work is to study the interface bond strength of UTW newlineoverlays subjected to different interface treatment techniques. Because loss of bond and newlinelayer delamination affects the composite behavior of UTW overlay. This will leads to newlinepremature failure and reduction in design service life of UTW overlays. Therefore, a newlinegood surface preparation method is required to improve the interface bond strength and newlineto meet the design service life of UTW overlays. In order to achieve the objective of newlinethe present work experimental studies were conducted under laboratory conditions. An newlineoptimized cementitious fiber reinforced concrete (FRC) mix proportion for UTW was newlinearrived using Taguchi method. The HMA mixture specimens of cylindrical and prism newlinewere casted using superpave gyrator and compression loading machine, respectively. newlineLater, HMA-UTW composite specimens such as cylindrical and prism were casted with newlinedifferent interface treatment techniques. The different interface treatment techniques newlineadopted for cylindrical specimens are single groove (SG), double groove (DG), piercing newlineand piercing with different percentage of bonding. The HMA-UTW prism composite newlinespecimens with different percentage of bonding at the interface were adopted. To newlineenumerate the interface bond strength for different interface treatment techniques two newlinetest methods were adopted namely direct shear test and flexural test. Both the tests were newlineconducted under (i) static and (ii) dynamic loading conditions newlineFrom direct shear test the effect of different interface treatment techniques on newlineinterface shear bond strength, k-modulus and number of cycles at failure were obtained. newlineSimilarly, in the flexural test, the flexural bon