Effect of mix proportion on the structural and functional properties of pervious concrete paving mixtures

Abstract

In recent years, pervious concrete pavement (PCP) is emerging as a novel pavement technology that is gaining a lot of attention amongst academicians due to its storm water runoff capabilities and mitigating urban heat island. This pavement technology consists of special types of concrete which has little amount of fines or no fines and interconnected voids. The different types of aggregate gradation, water-to-cement (w/c) and cement-to-aggregate, and compaction techniques with variations in efforts plays an important role in providing an optimum balance in the mixture designing of PCP mixtures. Therefore, the present study is an attempt to explore the possibility of variation of different aggregate gradation types with different proportion of w/c ratios for the production of PCP mixtures. Also, to study the effect of these mix properties on structural, functional as well as durable properties of PCP mixtures. Five aggregate gradation types and variability in w/c ratios were adopted in the present study viz. G1, G2, G3, G4 and G5, respectively. G1 and G2 consisted of larger-sized and well graded aggregates, while, G4 and G5 consisted of natural fines in proportion of 5% and 10%. Meanwhile, G3 consisted of binary blended single-sized aggregates: 30% of 10 mm and 70% of 4.75 mm. The above considered gradations were studied for porosity, density, permeability, compressive strength, flexural strength, and resistance to sulphate attack, at varied w/c ratios 0.30, 0.35, and 0.38, respectively. From an extensive laboratory investigation, it was observed that the G3 mix showed the best-balanced relation between all the afore-stated parameters, required for PCP mixtures. Hence, it can be recommended that the utilization of binary blended single-sized aggregates at a w/c ratio of 0.35 would provide an optimal solution keeping in mind the desired parameters of pervious concrete pavement mixtures are met.