Abstract:
Self consolidating concrete (SCC) is the new emerging technology in the construction industry offering great flexibility of placement in situations of congested reinforcement and complex structural elements leading to higher construction speeds and reduced labor. Self consolidating concrete (SCC) consists of a system of different sized aggregates like normal concrete. The cement paste fills the voids of the aggregate system and provides workability / flowability to the SCC in fresh state as the paste is vehicle for aggregate part of the mix. Literature suggests that some negative properties of SCC like creep and shrinkage are directly related to the paste content and also the cost of powder to form the paste is much higher as compared to other constituents in the SCC. Therefore it is highly desirable to reduce the paste content in SCC. This can be achieved by optimizing the aggregate grading curve in order to minimize the void content of the aggregate system. The reduced void content of the aggregate system will consequently leads to lower paste demand for providing the standard workability / flowability requirements of SCC. The present study focuses on the determination of the optimized grading curve for the self consolidating mortar system. The objective was achieved by following the Modified Andreassen Model and studying the effects of packing density of fine aggregate on the fresh and hardened properties of the self consolidating mortar systems. The packing density of fine aggregates varies with the distribution modulus of the Modified Andreassen Model, for present study the distribution modulus was varied from „0.20‟ to „0.50‟ and it was found that the grading curve with distribution modulus of „0.35‟ produces the highest packing density; resulting in minimum voids content (about 35.7%) in the aggregate mix hence bringing higher flowability, improved durability and strength self consolidating mortar systems. Based on the results it can be stated that packing density affects the properties of self consolidating mortar system and Modified Andreassen Model can be used for design and optimization of SCC mixes.
