NO-FINE LIGHTWEIGHT AGGREGATE CONCRETE MODIFIED WITH STYRENE BUTADIENE RUBBER

Abstract

No-fines concrete is a form of lightweight concrete obtained when fine aggregate is omitted. No-fine concrete mainly used for both load bearing and non-load bearing for external walls and partitions and in in-filling panels in framed structures. The essential objective of this work is to investigate the effect of incorporation of polymer (SBR) on the performance of no-fine concrete made from lightweight aggregate (porcelinite) and to suggest possible applications of this type of concrete. Three concrete mixes with different aggregate/cement ratios (A/C) (6:1, 8:1 and 10:1) by volume were selected. Each of these mixes included six mixes which differed in polymer/cement ratios, (0%, 5%, 10%, 15% and 20%) by weight to find the optimum polymer/cement ratio. Density, compressive strength, splitting tensile strength and drying shrinkage were conducted on all concrete mixes. The test results showed that the compressive strength of no-fine lightweight aggregate concrete increased with the increase in polymer/cement ratio up to 15%, and the compressive strength reduced at polymer /cement ratio of 20% . At polymer/cement ratio of 15%, the percentage of increase in compressive strength measured relative to reference mixes was about 50%. On the other hand, the splitting tensile strength was increased with the increase in polymer/cement ratio for all mixes. The percentage of increase in splitting tensile strength compared with reference mixes increased fr0m about 30 to 90% with the increase of polymer/cement ratio fr0m 5 to 20 %. Also the drying shrinkage strains of no-fine concrete decrease, with the increase in polymer/cement ratio. The percentages of decrease in drying shrinkage strain at 56 days were fr0m 5 to 30% with the increase of polymer/cement ratio fr0m 5 to 20%.