Xử lý đá phế phẩm thành cát nghiền và nghiên cứu tính công tác của hỗn hợp bê tông thương phẩm sử dụng cát nghiền

Abstract

This study provides a background for using of recycled materials in the production of commercial concrete, to provide a solution for the source of waste materials in quarrying and to replace natural sand. This study carried out the survey and assessment of crushed-sand sources and waste rock (the grain diameter is less than 5 mm) in ​​Da Nang city. Material sampling, testing and quality assessment were conducted according to TCVN 9205-2012 standard. Research results show that current material source has not met the criteria of aggregate particles used in cement concrete. It is necessary to take steps to treat the ratio of fine particles by washing decantation, wet sorting or dry separating in the fine-grained processing stage of crushed sand production technology for local waste rock sources. The study focused on the design of the commercial concrete mix using treated ground sand to replace river sand at a rate of 0%, 30%, 50%, 70% and 100% on a guaranteed basis. on work (slump) 16 ± 2 cm, slump retention for more than 90 minutes and ensure strength criteria for concrete.