Experimental study on properties of pervious concrete made with recycled aggregate

Abstract

This paper investigates recycled aggregate (RA) obtained from construction waste, with a particular focus on the properties of pervious concrete. The authors reveal the mechanical performance and permeability of pervious concrete with regard to volume fraction of the binder (binder/voids between aggregate), type of binder (cement paste and styrene-butadiene latex modified paste), particle size of aggregate, and aggregate to cement ratio. The three nominal diameters of the aggregate were 3.6 mm, 7.2 mm and 11.1 mm. The volume fraction of the binder ranged between 0.3 and 0.5, by varying the nominal diameter of the aggregate. The authors designed and cast concrete specimens with water to binder ratios (w/b) of 0.35. The authors conducted laboratory testing of mixture proportions for various properties, such as workability, unit weight, compressive strength, flexural strength, porosity and permeability. The results show that mechanical strength decreases as permeability increases. Decreasing the aggregate to the cement ratio enhances mechanical strength but may reduce permeability, and styrene-butadiene latex greatly enhances flexural strength. From an economic point of view, the authors' recommendation to achieve optimal strength and permeability in pervious concrete using recycled coarse aggregate is: w/b=0.35, nominal diameter of 11.1 mm for the recycled aggregate; the volume fraction of 0.5 for the binder; and aggregate to cement ratio of 3.9. The permeability coefficient for the above mentioned mix was 0.33 cm/sec with the 28-day compressive strength and flexural strength reaching 12.6 MPa and 2.1 MPa, respectively. The mixture for RA pervious concrete developed in this study satisfies the typical requirement for concrete sidewalks and is thus applicable for civic paving projects.