Evaluation on compactibility and workability of roller-compacted concrete for pavement

Abstract

ABSTRACTThe use of roller-compacted concrete pavement or RCCP has increased steadily in the past few decades. It is an economical version of conventional concrete pavement; whereas the construction cost of other types of pavement is constantly rising. In its mixture design, compactibility is an important factor for achieving high strength while workability is an essential factor for providing workable material. However, the satisfaction of both properties is difficult to achieve because of the effect of various factors such as aggregate gradation and water content. Appropriate combination of materials is significant for providing adequate compactibility and workability of this concrete. In this study, twenty-one mixtures of roller-compacted concrete (RCC) with six different water contents for each of four aggregate gradations were evaluated using Modified Proctor and Vebe tests. Dry density was used to characterise compactibility of RCC while Vebe time was used to express its workability. It was found that Vebe time increased as sand/aggregate, or s/a, ratio increased and decreased when water content rose. On the other hand, maximum dry density decreased as s/a increased. The well-graded aggregates, 58 and 50% of s/a, were found to give its maximum dry density with satisfactory workability. Interestingly, it was learned that the range of appropriate water content corresponding to acceptable workability is narrower than that of appropriate water content corresponding to the acceptable dry density which indicated that it is more crucial and difficult to get appropriate workability than acceptable dry density.