Evaluation of Self-Consolidating Concrete Mixtures used with Mineral and Chemical Admixtures​

In this study, we evaluate past academic research on “Self-Consolidating Concrete” (SCC) that uses different combinations of mineral and chemical admixtures to achieve similar fresh properties and hardened properties of conventional Portland Cement Concrete (PCC) with flowable characteristics. The mineral admixtures such as fly ash, slag, metakaolin and Rice Husk Ash (RHA) are the waste byproduct materials usually dumped in landfills. Previous studies mainly discussed the effects of fly ash and superplasticizers on improving the workability and flowability of  SCC. The use of high volume fly ash (HVFA) replacements in concrete have generally been known to encounter problems such as low early strength developments and delayed setting time during cold weather. Through the evaluation of the mineral admixtures such as slag, silica fume, metakaolin, and RHA, it was found that the toughness, stability, and durability of the SCC mixtures were improved when combined with HVFA. Different combinations of admixtures in SCC have shown varying results, such as changing the concentration of certain admixtures may invalidate the concrete mix that it no longer can be classified as SCC. On the other hand, experiments have also shown that the use of optimum SCC mixture combinations improved the fresh and hardened concrete properties. The maximized utilization of fly ash content in concrete with the addition of slag, silica fume, and RHA to achieve SCC properties will reduce the demand for cement mining, hence significantly reducing the carbon footprint of the industry. Also, the use of the byproduct materials such as fly ash, slag, metakaolin and RHA may lower the cost of producing usable concrete, thus can prevent those byproducts from being dumped into the landfills.