Author(s)

A R Khaloo, Y Khalighi & M Irajian

Abstract

No-fines concrete has considerable drainage property and a relatively low strength. A wide aggregate grading range, with higher percentage of aggregate in lower bound, improves strength properties, however such grading results in lower drainage capability. The objective of this paper is to make high- performance single-sized No-fines Concrete mixes using polymer modification. An experimental program was carried out to study the parameters of water- cement ratio, aggregate-cement ratio, type of polymer, polymer content, setting time and curing period. The test specimens were 6x12 in. cylinders and were cast using hand rodding compaction in accordance with ASTM C 31-69. Initially a proper capping method was established to minimize its influence on the concrete strength. Then water-cement ratio of the concrete was optimized based on elimination of aggregate segregation in the fresh concrete and reaching the highest possible strength. Later, two mixes with different ratios for aggregate- cement were selected, one with low cement content, and another with high cement content. These mixes were polymer modified by Styrene-butadiene and Acrylic latex. Test results indicate that Styrene-butadiene polymer improves the strength performance of low-cement No-fines concrete, however Acrylic latex is beneficial in both mixes, The Acrylic modified mixes were more time sensitive than the Styrene-butadiene mixes. As a result, the Styrene-butadiene mixes are more applicable in practice.

Keywords