Effects Of Aggregate Shape, Aggregate Size, And Water-To-Cement Ratio on Compressive Strength, Permeability, And Abrasion Resistance of Pervious Concrete Mixture

Abstract

Impermeable concrete often contributes to the extent of flooding prevalent in the Philippines, as it prevents natural infiltration of runoffs to the ground. One appealing solution to this problem is the application of pervious concrete, whose high void content allows water to pass through it. However, due to this property, its compressive strength is compromised. Other important properties necessary for pavement, like abrasion resistance, have not been thoroughly studied yet, as well - locally. As part of preliminary studies for the applicability of pervious concrete as part of the pavement system, this paper aims to evaluate the effects of aggregate size, aggregate shape, and water-to-cement (w/c) ratio on the compressive strength, permeability, and abrasion resistance of the concrete mixture. In this study, it was found that the compressive strength and permeability rate are higher for pervious concrete made of angular aggregates, and there is not much difference in the abrasion resistance between the samples made from either angular or round aggregates. An optimized pervious concrete mixture was also obtained, consisting of single-sized 9.5 mm angular aggregates with a w/c ratio of 0.306. This led to a theoretical maximum compressive strength of 22.696 MPa and corresponding permeability of 3.93 mm/s, which is applicable for low-traffic pavements like parking lots. Furthermore, a Spearman correlation value of 0.207 showed that there is a weak, positive relationship between the compressive strength and the percent weight loss of the concrete due to abrasion. This means an inverse relationship between the compressive strength and abrasion resistance exists. However, the finding may not be the actual relationship between the two, as the p-value on the Spearman correlation exceeded the significance value of 0.05.