MODULUS OF ELASTICITY AND ULTRASONIC PULSE VELOCITY OF CONCRETE CONTAINING POLYETHYLENE TEREPHTHALATE (PET) WASTE HEATED TO HIGH TEMPERATURE

Abstract

This study aims to produce and optimize Eco-efficient self-compacting concrete (SCC) mixes using multiwaste substitutions. The main input parameters of mixes were total binder, fine aggregate and water contents whereas slump flow and compressive strength were the two main operational responses of produced concrete. Limestone powder (LP) and waste Polyethylene Terephthalate (PET) were used in concrete as parts of cement and fine aggregate respectively with high range water reducing admixture (SP) as part of water. Response Surface Methodology (RSM) and multi-objectives optimization using Minitab 17 statistical software were employed for this purpose. Twenty SCC mixes were designed and checked experimentally using Central Composite Design (CCD) concept in RSM. Mathematical models were established and evaluated using analysis of variance test (ANOVA) according to the experimental results. This is in order to define the effectiveness degree of design parameters on the properties required and to adjust the derived mathematical models. Multiobjectives optimization process was adopted to determine the optimum values of the input parameters. The optimization revealed that the optimum values of the input factors, LP, PET and SP were 20.1%, 2.4% and 1.16% by weight respectively. These theoretical values were checked experimentally and the achieved responses were quiet similar or higher than the best proposed mix. It was deduced that the developed models can be used to ensure a speedy mix design process by achieving maximum tested properties of eco-efficient SCC.