Impact Resistance of Styrene-Butadiene Rubber (SBR) Latex-Modified Fiber-Reinforced Concrete: The Role of Aggregate Size.

Muhammad Rehan Ashraf,Nauman Khurram,Ahmed F Deifalla,Usman Akmal,Fahid Aslam

doi:10.3390/ma15041283

Abstract

Improvements in tensile strength and impact resistance of concrete are among the most researched issues in the construction industry. The present study aims to improve the properties of concrete against impact loadings. For this purpose, energy-absorbing materials are used along with fibers that help in controlling the crack opening. A polymer-based energy-absorbing admixture, SBR latex, along with polypropylene fibers are used in this study to improve the impact resistance. Along with fibers and polymers, the effect of the size of aggregates was also investigated. In total, 12 mixes were prepared and tested against the drop weight test and the Charpy impact test. Other than this, mechanical characterization was also carried out for all the 12 concrete mixes. Three dosages of SBR latex, i.e., 0%, 4%, and 8% by weight of cement, were used along with three aggregates sizes, 19 mm down, 10 mm down, and 4.75 mm down. The quantity of polypropylene fibers was kept equal to 0.5% in all mixes. In addition to these, three control samples were also prepared for comparison. The mix design was performed to achieve a normal-strength concrete. For this purpose, a concrete mix of 1:1.5:3 was used with a water to a cement ratio of 0.4 to achieve a normal-strength concrete. The experimental study concluded that the addition of SBR latex improves the impact resistance of concrete. Furthermore, an increase in impact resistance was also observed for a larger aggregate size. The use of fibers and SBR latex is encouraged due to their positive results and the fact that they provide an economical solution for catering to impact strains. The study concludes that 4% SBR latex and 0.5% fibers with a larger aggregate size improve the resistance against impact loads.

Highlights

Concrete is widely used in various civilian and military buildings in Pakistan and is one of the most important construction materials used all over the world
The compressive strength results indicate that all concrete mixes attained the value of compressive strength, ranging from 27 MPa to 38 MPa, which can be considered as normal-strength concrete
When fiber was added to concrete, the strength of the fibrous mixes was slightly dropped, and this observation is in line with the previous research studies on fiber-reinforced concrete

Summary

Introduction

Concrete is widely used in various civilian and military buildings in Pakistan and is one of the most important construction materials used all over the world. Terrorism is the biggest problem of many countries on the globe these days. Among these countries, Pakistan has witnessed many major terrorism attacks on important public and private sector buildings in the recent past, which inflicted many deaths and left hundreds with wounds. It has been observed that the major cause of loss of life was the severe damage of structural elements during terrorist attacks resulting in the failure of the building. Investigations have highlighted that the conventional concrete used in those structures subjected to blast loadings was not resistant enough to bear such high strain loadings [1,2]

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Conclusion