Mechanical Properties of Crumb Rubber Mortar Containing Nano-Silica Using Response Surface Methodology.

Syafiqah Shahrul,M M A Wahab,Bashar S Mohammed,M S Liew

doi:10.3390/ma14195496

Abstract

Crumb rubber (CR) from scrap tires is used as a partial replacement of fine aggregates in cement paste. This promotes the sustainable development of the environment, economy, and society, as waste tires are non-biodegradable and flammable. They occupy large landfill areas and are breeding grounds for mosquitoes and rodents. Inclusion of CR in mortar leads to several improvements on the mixture properties such as ductility, toughness, and impact resistance. However, it exhibits lower strengths and Modulus of Elasticity (ME). Therefore, to promote the use of mortar containing CR, it is vital to improve its mechanical strength. Past studies proved that nano-silica (NS) improves the strength of concrete due to the physico-chemical effects of NS. This study aims to examine the mechanical properties of crumb rubber mortar containing nano-silica (NS-CRM) and to develop models to predict these properties using Response Surface Methodology (RSM). Two variables were considered, CR as partial replacement to sand by volume (0%, 7.5%, 15%), and NS as partial replacement to cement by weight (0%, 2.5%, 5%). The results demonstrated a significant improvement in the mechanical properties of CRM when incorporating NS, and the models developed using RSM were acceptable with a 2% to 3% variation.

Highlights

As the world’s population grows, so does the need for automobiles, especially in urban areas [1]
Reuse of scrap tires in construction will contribute to environment-friendly solutions for scrap tire disposal problems
Extensive research works conducted on concrete containing-crump rubber (CR) as partial replacement to fine aggregate are well documented

Summary

Introduction

As the world’s population grows, so does the need for automobiles, especially in urban areas [1]. Scrap tires are flammable and non-biodegradable, due to the presence of stabilizers, additives, and the cross-linked structure of the elastomeric polymer material [3], and they pose serious environmental, health, and aesthetic problems globally. They are bulky and require a large area in landfills. Due to their convex shape, they provide excellent breeding grounds for mosquitoes and rodents. Extensive research works conducted on concrete containing-CR as partial replacement to fine aggregate are well documented. Research works on mortar containing CR are scarce and very limited

Objectives

Methods

Results