Influence of crushing index on properties of recycled aggregates pervious concrete

• Published in: Construction & building materials 2017-03, Vol.135, p.112-118
• Main Authors: Zhang, Zhiquan, Zhang, Yufen, Yan, Changgen, Liu, Yunxiao
• Format: Article
• Language: English
• Subjects: Analysis; Chemical properties; Crushing index; Mechanical properties; Permeability; Pervious concrete; Recycled aggregates; Recycled materials; Statistics; Water permeability
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2016.12.203

•Natural aggregate was replaced with discarded concrete and clay brick aggregates.•Addition of recycled clay brick aggregates increases the crushing index.•Increase of crushing index exerts a negative impact on mechanical properties.•The effects of crushing index on the porosity and permeability can be ignored. In this study, recycled aggregates (RA) produced by mechanical shredding from discarded concrete and clay bricks were used to make pervious concrete. Six groups of recycled aggregates pervious concrete (RAPC) were designed with different crushing index of aggregates under the condition of same concrete mixture ratio. The crushing index of aggregates increases with the replacement of RA increases. Experiments about compressive strength, elasticity modulus, flexural strength, permeability coefficient, total void ratio were conducted, including freezing and thawing cycle test. Test data of RAPC indicated that compressive strength, flexural strength and elasticity modulus of 28days decreased by 36%, 28% and 21% respectively when crushing index changed from 9% to 37%, simultaneously strength loss rate increased from 6.6% to 18.7% and mass loss rate increased from 2.3% to 8.5%. Especially when crushing index is greater than 24%, except permeability coefficient and total void ratio, other properties of RAPC decreased significantly due to the lower quality of RA. Therefore, experimental results show that increase of crushing index has significant effects on compressive strength, elasticity modulus, flexural strength and freeze-thaw durability of RAPC. However, the effects of increasing crushing index on the permeability coefficient and total void ratio of RAPC can be ignored.