Strength and stiffness properties of the optimum mix composition of cement-less wastepaper-based lightweight block (CWLB)

Abstract

The cement-less wastepaper-based lightweight block (CWLB) is a newly developed eco-friendly non-load bearing block manufactured from majorly cellulosic wastes without the use of cement. The main constituents of CWLB includes; wastepaper aggregate (WPA) produced from post-consumer wastepaper, waste additive and sand. This study was conducted to determine its optimum mix composition and the corresponding strength and stiffness properties. The experimentations carried out covered; the optimization of the mix composition of CWLB using the Taguchi statistical optimization technique (TSOT) and the determination of the compressive strength, density, elastic modulus and the ultrasonic pulse velocity (UPV) of the optimal CWLB specimen. The findings from the TSOT ascertains that the optimum mix composition of CWLB comprises of processing parameters including; 2.5 WPA/sand ratio, 0.75 water/binder ratio, and 3.5 Metric ton (i.e. 13.7 MPa) compacting force. Also, it was found that the optimal CWLB exhibited; an average compressive strength of 2.71 MPa, an average density of 901.5 kg/m3, an average UPV of 989.9 m/s and an estimated elastic modulus of 883.4 MPa. The comparison of these properties with the applicable standard requirements indicates the suitability of CWLB for non-load bearing application. In addition, the presence of 75% waste content in the mix composition of CWLB indicates its eco-friendliness and its potential to contribute to the sustainability in the construction industry through reduction in natural resources consumption. The innovation presented in this study includes; the development of a suitable optimum mix composition of constituent materials for the novel CWLB, the identification of factors that affects it strength properties and the determination of its engineering properties. Future work will investigate other relevant properties of CWLB which include; capillary water absorption, thermal conductivity, and the reaction to fire.