Review of self-compacting concrete mix design methodology and the assessment of fresh properties

Abstract

Self-compacting concrete (SCC) is a highly workable concrete which does not require any external vibration for compaction. In its fresh state, SCC is proportioned to flow under its own weight through dense reinforced formworks without segregation and bleeding. This dissertation was done in order to evaluate self-compacting mortar (SCM) and selfcompacting concrete in their fresh and hardened properties. The work was performed to develop an experimental based mix-design methodology based on previous studies. Due to the high demands on the fresh properties requirements, the mix design process is complex when compared to normal vibrated concrete (NVC). SCC has higher content of powder material such as cement and mineral admixtures (in addition to cement), when compared to NVC. A number of mix design methodologies from various studies focused on the SCC mix proportions and its effects in its fresh state. These were briefly reviewed in this study for comparisons of results. This study also included the effects when replacing part of the cement content with globigerina limestone filler (GLF) and calcium carbonate filler (CC). The effect of both fillers were investigated with a series of paste mixes prepared with different water to powder ratios (W/P) and super plasticiser (SP) dosages. The miniature cone, mini slump cone and the marsh cone were used to assess the paste fresh properties. The effects of aggregate grading, size shape, angularity and texture of the upper coralline limestone (UCL) were evaluated to obtain the required paste volume for the selected type of aggregate used in this study. Subsequently, the mortar mixes were proportioned by volume. A number of mortar mixes were designed by replacing part of the cement content with either the GLF or CC filler. The aim was to reach same workability levels using the GLF to that achieved by CC mortar mixes at different SP % dosages. The mini slump flow and mini v-funnel were used to test the mortar fresh properties. The hardened properties were also studied to compare the compressive strengths between the two filler mixes. Finally, a number of trial mixes were done for SCC with CC filler and compared to with the previous studies.