Performance of natural rubber latex modified concrete in acidic and sulfated environments

Abstract

Deterioration of concrete due to chemical aggression is a serious menace to the two major properties of concrete; strength and durability. Hence, precautionary measures towards curtailing chemical attack on concrete could be of great importance. This paper reports experimental findings regarding performance of natural rubber latex (NRL) modified concrete in acidic as well as sulfated environments. Normal and modified concretes were developed and subjected to two simulated aggressive curing mediums; 5% sulfuric acid (H2SO4) and 2.5% sodium sulfate (Na2SO4). Latex/water ratio was varied from 0% to 20%. Concrete phases were studied through SEM. In addition, capacities in moisture ingress, being the main gateway to chemical attack on concrete was also investigated through water absorption test. Results have shown that inclusion of appropriate quantity of latex into concrete plays a significant role in curbing attack from H2SO4 and Na2SO4. For instance, considering Na2SO4 alone, strength gain in the modified concrete was 86.2% higher than the corresponding value in normal concrete within a period of 84 days. However, physical observations revealed a high volume change associated with latex in the modified specimens subjected to H2SO4 which suggests attack by acidic agents on hydrocarbon substances.