Abstract
Roller compacted concrete (RCC) has similar properties as conventional concrete; it is brittle, less ductile and has poor tensile strength. When used for pavement applications, it is also subjected to repetitive fatigue loads and flexural stresses. In addition, dowel bars or reinforcement cannot be used due to the way it is consolidated. These shorten the pavement life and increase the cost of maintenance. Therefore in order to reduce these defects by reducing the pavement deterioration and improving its service life, one of the possible ways is by incorporating additives such as polymers, fibers or crumb rubber (CR) into the RCC mix where it will absorb the deformation and strain energy caused by the repetitive loadings. The aim of this study was to improve the flexural strength, flexural toughness and ductility of RCC pavement. CR was used to partially replace fine aggregate at different percentages (0%, 10%, 20% and 30%) to produce roller compacted rubbercrete (RCR), and nano silica (NS) was added by weight of cementitious materials at 0%, 1%, 2% and 3% to mitigate loss in strength caused by CR. The findings showed that both flexural toughness and ductility index of RCC increases with increasing CR content. Similarly, the flexural strength of RCR increases for up to 20% replacement of fine aggregate with CR. The addition of NS increases the flexural strength of RCR; however it decreases toughness and ductility index, thereby making the RCR more rigid. Lastly response surface methodology (RSM) analysis was used to develop model for predicting the flexural toughness and ductility index of RCR using CR and NS as the variables. The analysis of variance (ANOVA) showed that the developed models have a good degree of correlation and predicting ability. (C) 2017 The Authors. Published by IASE. This is an open access article under the CC BY-NC-ND license.