1 گروه مهندسی عمران، واحد قزوین، دانشگاه آزاد اسلامی، قزوین، ایران
2 گروه مدیریت ساخت، دانشکده مهندسی کاربردی، فناوری و ایمنی، تهران، ایران دانشگاه میلرزویل، میلرزویل، پنسیلوانیا، ایالات متحده آمریکا
عنوان مقاله [English]
This study deals with the development of an environmentally sustainable roller compacted concrete (RCC). Response surface methodology (RSM) has been used to design and optimize the mixtures. The variables used were; high volume fly ash (HVFA) at 50%, 60%, and 70% replacement by volume; crumb rubber at 10%, 20%, and 30% replacement by volume of fine aggregate; nano silica at 0%, 1%, and 2% addition by weight of cementitious materials. Multi-objective optimization was carried out to determine the optimized mixtures by maximizing the 28 days compressive, flexural and splitting tensile strength. An optimized HVFA RCC mix can be achieved by partially replacing 10% fine aggregate with crumb rubber by volume, replacing 53.72% of cement with fly ash by volume, and the addition of 1.22% nano silica by weight of cementitious materials. To further study the effect of crumb rubber and nano silica on the properties of HVFA RCC, new mixtures were prepared using a constant fly ash content as replacement to cement (50%) and varying the percentage replacement of fine aggregates with crumb rubber (at 0%, 10%, 20%, and 30%), and the percentage addition of nano silica at (0%, 1%, 2%, and 3%). Compared to conventional RCC pavement, HVFA RCC exhibited lower fresh density, Vebe time, compressive strength, splitting tensile strength and flexural strength compared to conventional (control) RCC pavement. However, at after 1 year, HVFA RCC pavement shows higher compressive strength than the conventional (control) RCC pavement. Partially replacing fine aggregate with crumb rubber leads to a reduction in fresh density, Vebe time, compressive strength, flexural strength and splitting tensile strength. The addition of nano silica increases the Vebe time, fresh density, compressive strength, flexural strength, splitting and tensile strength of HVFA RCC.