Enhancing Compressive Strength of Pervious Concrete for Use as Pavement Layer in Urban Roads Aper

Abstract

South African Drainage and Stormwater Systems in urban roads has been of great concern, more so with recent flash floods in Gauteng and KwaZulu Natal Province in South Africa. Pervious concrete can be used to mitigate these challenges for urban roads. Pervious concrete is a concrete that contains no fines or only a small amount is added for binding. It consists of single sized rounded aggregates between 9.5mm to 12.5mm and bonded by cement and water at points of contact to create a high porosity system that drains water. The research focused on developing different structural pervious concrete mixes, with varying (a) aggregate sizes (7mm, 9.5mm and 19mm) (b) including (river fine aggregates, rubber flakes, fly ash and steel reinforced fiber) and combinations thereof. Results indicated that strong pervious concrete mixes can be developed using a combination of 9.5mm aggregate, river fine aggregates and fly ash, with a recorded maximum yield of 25MPa, and an accompanying Voids Content of 16%. Furthermore, against this performance, it was found that final compressive yield strength of 25MPa falls shy of the 35MPa COTO standard specifications for road and bridge works for south African road authorities (2020 edition). The derived pervious concrete mix was found to satisfy Class 4b Minor Collector Arterial in urban zones, with capacity to withstand up to 10 000 Average Daily Traffic