Improved mechanistic performance of natural rubber latex modified pavement concretes in sulfate environments

Abstract

ABSTRACT Sulfate attack causes significant degradation in the concrete matrix, including softening, expansive cracking, and other disruptive processes. This research examined the impact of incorporating a Natural Rubber Latex (NRL) additive on the mechanical and durability improvement of concrete pavements. The study evaluated the influence of water to cement (w/c) ratios and dry rubber to cement (r/c) ratios on compressive and flexural strengths, as well as flexural fatigue characteristics, before and after immersion in a 5% sulfate solution at various intervals. Optimal r/c ratios for the highest flexural strength and fatigue life were 0.58, 1.16, and 1.73 for w/c ratios of 0.3, 0.4, and 0.5, respectively. The highest durability was achieved at an r/c ratio of 5.78, resulting in a compressive strength loss of 4.2–7.7 times lower compared to that of normal concrete, hence extending the service life against severe environment. The fatigue model equation proposed by the Portland Cement Association (PCA) was utilised to predict the fatigue life of both normal and NRL-concretes. The outcome of this research will lead to a fundamental knowledge in the development of a design guideline of sustainable concrete pavements, and eventually promote the usage of NRL, which is abundant in Southeast Asia, including Thailand.