Effects of different mineral additives on self-compacting concrete properties

Self-compacting concrete (SCC) is a special type of concrete that has become widespread in the construction sector due to its high fluidity. SCC has the ability to fill the frame works without any need for vibration and that reduce the noise pollution generated by vibration in frequently equipped building elements. SCC production is increasing rapidly due to its advanced features and advantages in terms of application. However, there were problems with sustainability in relation to materials used in SCC production, and the environmental impacts caused by the concrete industry have been a major concern in recent years. In addition, Portland cement (PC) production, an important component of SCC, is responsible for the consumption of approximately 13% of the world's industrial energy and approximately 7% of global CO2 emissions. In SCC, PC is replaced by fly ash (FA), ground granulated blast furnace slag (GGBFS), silica fume (SF) etc. The use of puzolanic additives not only reduces the total material cost of SCC, but also makes significant contributions to sustainable development and reducing environmental impacts. The utilizing of FA and GGBFS as minerals admixtures in SCC improves the physical, mechanical and durability of concrete in fresh and hardened situations. The aim of this study was the investigation the effect of different mineral admixtures on physical and mechanical properties of SCC by using ground granulated blast furnace slag (GGBFS), fly ash (FA) and perlite powder (PP) as cement substitution. Cement substitutions percentages were 35%,45% and 55% for GGBFS, 10%, 20% and 30% for FA and 0%, 5% and 10% for PP. In order to investigate the effect of curing conditions on SCC performance, SCC samples were cured in a standard normal water cure (NC) (23.5 ±2 °C) and controlled temperature and humidity (32±2 °C and 70% relative humidity) environment (LC) to simulate hot air and high humidity conditions. The compressive strength was determined in 3, 7, 28 and 90 days. Freeze – thaw according to ASTM C666 and ultrasound velocity pulse tests in were applied to 28-day samples. The results showed that LC curing method was effective on the compressive strength in 3 and 7 age of concrete. Reference mix showed the highest compressive strength in early age. however, the mix with 30% of FA, 35% of GGBFS and 5% of PP showed the highest results of compressive strength in 90 days.