Evaluation of Laboratory Methods of Determination of SBS Content in Polymer-Modified Bitumens.

Maria Ratajczak,Artur Wilmański

doi:10.3390/ma13225237

Abstract

The article deals with the issue of determination of the content of SBS (Styrene-Butadiene-Styrene) in polymer-modified bitumens (PMBs). The effect of SBS copolymer on the physical and rheological properties of bitumens has been thoroughly investigated and widely described in the literature. Condition surveys of structures and evaluation of the properties of materials used at construction sites have become a huge challenge for construction engineering. Determination of the content of SBS modifier in various building materials (asphalt mixtures and bituminous waterproofing compounds) is a good example in this respect. Based on the laboratory tests, mid-infrared spectroscopy was found to be the most effective analytical method. It can be used for easy detection of the presence of SBS in a modified bitumen. However, quantitative analysis is an issue that calls for research. Currently, there are no standard guidelines, whether national or European, that would regulate the method of testing. Three test methods were assessed in this study: the AASHTO T302–15 standard method and two Australian methods described in codes of practice (T521 and Q350) developed by the local authorities, which define a standard way of determining the amount of SBS in polymer-modified bitumens. The tests were carried out on standard controls and samples sourced from the industry. The above-mentioned test methods were assessed in terms of accuracy of determination, reliability of results obtained on the industrial samples, level of complexity of the test procedure, sample preparation techniques and the type of the required reagents.

Highlights

Bitumen became a popular building material quite recently, namely at the beginning of the 20th century and already at that time the first modification attempts to improve its performance were made [1,2,3]
The developed methods of determination of SBS content in modified bitumens were verified through testing of industrial samples
A small variability was noted in the SBS contents measured on the industrial samples (Figure 8) among the controls, samples after RTFOT and samples recovered from hot mix asphalts (HMAs)

Summary

Introduction

Bitumen became a popular building material quite recently, namely at the beginning of the 20th century and already at that time the first modification attempts to improve its performance were made [1,2,3]. Systematic research on the effect of various admixtures on the properties of bitumens began in the late 1960s and early 1970s. The purpose of modification is to improve the bitumen’s properties, widen the viscoelastic region of the bitumen behavior or increase its resistance to permanent deformation [5,7,8]. The history of SBS as a modifier started with the need to recycle waste, namely scrap tires, which after grinding into powder were added to bitumen. SBS was used primarily for production of sports footwear

Methods

Discussion

Conclusion