Physicomechanical Assessments and Heavy Metals’ Leaching Potential of Modified Asphalt Binders Incorporating Crumb Rubber and Tin Slag Powders

Ali Huddin Ibrahim,Ramadhansyah Putra Jaya,Kok Keong Choong,Sharvin Poovaneshvaran,Megat Azmi Megat Johari,Ashiru Sani,Mohd Rosli Mohd Hasan,Tracy Leh Xin Wong,Antonio Gloria

doi:10.1155/2021/2137957

Abstract

Industrial solid waste has been widely used as an alternative additive for bituminous material modification. This study aims to evaluate the basic properties and quantify the leaching potential of modified asphalt binders incorporating crumb rubber powder (CRP) from waste tires and tin slag (TS) for a local smelting company. Three percentages of CRP and TS, at 5, 10, and 15%, were considered. The conventional asphalt binder (PEN 60/70), CRP, and TS-based modified asphalt binders were analyzed for toxicity, softening point, penetration value, elastic recovery, torsional recovery (TR), and coatability index. The findings indicated that the addition of the waste materials led to no significant heavy metal content in the asphalt binder mix. Moreover, the basic and physical properties of the asphalt binders were also improved by 5, 10, and 15% of the waste, respectively. However, TS waste exhibited limited effects on all the parameters and had a 5% optimum dosage. The modified binders’ results showed that the CRP modified asphalt binders had fewer heavy metals and responded more to elastic recovery and coatability.

Highlights

In Malaysia, the escalated usage of vehicles on roads generates a huge amount of waste tires at the end of their life cycle [1]
The tires can serve as the crash barrier, a bumper, and an artificial reef [3, 6, 7]. e utilization of waste tires is effective in overcoming the issue associated with solid scrap tire disposal, and the recycled tires such as crumb rubber can act as a good modifier for enhancing the properties and performance of asphaltic concrete [2, 8, 9]. e utilization of polymer-modified bitumen is a cost-effective and efficient alternative to improve the performance of asphalt pavements [10, 11]
E collected leachates of the samples were analyzed for the heavy metals by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). e initial Toxicity Characteristic Leaching Procedure (TCLP) test was performed on raw material, namely, crumb rubber powder, tin slag, and unmodified asphalt binder

Summary

Introduction

In Malaysia, the escalated usage of vehicles on roads generates a huge amount of waste tires at the end of their life cycle [1]. Is issue can be overcome by recycling scrap tires to protect the environment from pollution [4, 5]. Since the last few decades, recycled waste tires are being utilized as a modifier in asphalt paving mixtures, additives in Portland cement concrete, and lightweight fillers. E utilization of waste tires is effective in overcoming the issue associated with solid scrap tire disposal, and the recycled tires such as crumb rubber can act as a good modifier for enhancing the properties and performance of asphaltic concrete [2, 8, 9]. The tires can serve as the crash barrier, a bumper, and an artificial reef [3, 6, 7]. e utilization of waste tires is effective in overcoming the issue associated with solid scrap tire disposal, and the recycled tires such as crumb rubber can act as a good modifier for enhancing the properties and performance of asphaltic concrete [2, 8, 9]. e utilization of polymer-modified bitumen is a cost-effective and efficient alternative to improve the performance of asphalt pavements [10, 11]

Objectives

Methods

Results