EFFECT POLYPROPYLENE OF FIBER ON DRYING SHRINKAGE CRACKING OF CONCRETE PAVEMENT USING RESPONSE SURFACE METHODOLOGY

In concrete when tensile stress surpasses the strength of the traction contributes to cracking, which is called shrinkage cracking. Shrinking allows for curling and folding of concrete. The principal goal of this research work is to develop optimal Eco-friendly concrete mixtures by using Response Surface Methodology (RSM), including different quantities of polypropylene fiber used in concrete pavement, identify the shrinkage factor (shrinkage cracking) in the concrete pavement. The testing program included using of thirty mixtures to investigate four parameters namely cement content (300,400 and 500) kg / m3, steel fiber (0, 0.075, and 0.15 vol. %), three separate amounts of polypropylene fiber (0, 0.35, and 0.7 vol. %), and (0, 5, and 10 %) silica fume by cement weight. The results indicated that the amount of cement is the higher factors affecting the shrinkage cracking of concrete. For the purpose of obtaining the best mixture for optimal components to design concrete mixtures used in the concrete pavement that give the compressive strength [> 30 MPa], flexural strength [> 4.1 MPa], minimum CO2 emissions, less cost, and fewer cracks width according to requirements and Iraqi specifications are cement [385.94] kg/m3, silica fume [0.000198Vol.%], steel fiber [0.0564 Vol.%], PP fibers [0.2926 Vol.%], Carbon dioxide emissions [379.59] kg CO2 -e / m3, total cost 99.96 USD / m3, and crack width [0.1]mm.