FLOW AND STRENGTH CHARACTERISTICS OF SCC CONTAINING LIMESTONE AND CHALK POWDERS

摘要

An investigation of the use of different types of limestone powders and chalk powder as fillers in Self-Compacting Concrete (SCC) and their effects on the flow and strength characteristics of the concrete mixes iS presented．With minor adjustments in the dosage of the superplasticiser,it was possible to develop concrete mixes with suitable self-compactability by using the limestone powders．The morphology of the powders had a significant influence on flow behavior and the best deformabilities were obtained in the SCC mixes containing the fine limestone powder whereas the coargcr chalk powder gave a relatively poor performance．Besides particle size，the shape of the powdcr particles also had a significant influence on deformabilitv．The deformability of the SCC mix with the relatively coarser but spherically shaped fly ash particles was comparable to that of the SCC mixes with the much finer but irregularly shaped limestone powder particles．The slump flow retentivity of the SCC mixes with the superplasticiser was monitored over a period of two hours after casting and was found to be satisfactory except jn the mixes with the coarser chalk powder．However,the plastic viscosity of the mixes with the higher powder addition Ievels Was found to significantly increase with time．The compressive strength of the SCC mixes containing the fine limestone powder was significantly greater at all ages than the controI SCC mix with the same powder content,particularly at early ages.