Pervious concrete pavement is a permeable pavement with a large volume of interconnected voids to satisfy the need for both pavement surface and storm water management. It is made from a mixture of cement, coarse aggregates, and water. However, it contains little or no sand, which results in a porous open-cell structure that water passes through. Enhancement of its physical and mechanical properties is the main objective of this work. Clogging is perceived as a major problem for permeable pavement, so this study is focusing on the clogging phenomena. Eight mixtures of pervious concrete were cast using polypropylene fibers (0.1, 0.15, and 0.2) % by volume of concrete and a waste industrial material (8, 10, 12) % partial replacement of cement as main variables in this research. The specimens were tested at 7, 28, 90 and 120 days. Physical tests included the evaluation of density, water absorption, permeability and clogging. Mechanical tests included the evaluation of compressive strength, splitting tensile strength and flexure strength. The results showed that using polypropylene fiber improved the mechanical properties and water permeability of pervious concrete. The waste industrial material improved the mechanical properties up to 10% replacement of cement. Also increasing the waste industrial material replacement ratio improved the clogging resistance.

Water plays an important role in the concrete industry. The research aims to study the effect of using seawater in mixing and curing concrete and indicating its effect on fresh properties of concrete such as slump and mechanical properties like compressive, tensile and flexural strength. The main variables of this paper are type of water (sea and fresh water), percentage of fly ash and metakaolin. The percentage of fly ash is 20%, 30% and 40% as a replacement of cement content. In addition, metakaolin with 3%, 5% and 7% as a replacement of cement content was used. Mineral admixtures are materials that have a softer degree compared to cement, and this leads to have denser concrete and less permeable concrete, which enhances the lower overall porosity of the system due to the filling of capillary pores. That leads to reduce the penetration of chloride and sulfate ions into the concrete. The results show that using mineral admixture gave the ability to use seawater in plain concrete, as a compressive strength of 49 MPa was achieved when seawater was used in mixing and curing concrete with 7% metakaolin and 30% fly ash. The results also showed an improvement in tensile and flexural strength.

Different methods were used to repair concrete cracks. Recently, microbial induced calcium carbonate precipitation is presented as a self-healing technique for concrete manufacture, which is proposed as an eco-friendly method. It is a bio-mineralization process. Microbial activities induced precipitation that can heal cracks. Effect of bio-mineralization in concrete by incorporation of ureolytic species such as Bacillus Megaterium is investigated. Fresh and hardened tests were carried out on concrete at various ages. "Bacillus Megaterium" (Bm) with a cell density of 2× CFU/mL was used when added to mixtures with two ratios of 0.5% and 0.25% of cement weight. Calcium lactate, Calcium acetate, and Calcium format were added as nutrition to bacteria by 0.25% and 0.125% of cement weight. Test results indicated that the inclusion of Bm in concrete enhanced properties. Bacteria addition and all nutritions used revealed varied decreases in the rate of water absorption and capillary permeability coefficient. Bm 0.5% with acetate nutrition concrete mix had a maximum increase in compressive strength at all ages. It had compressive strength value 152.99% of that of the compressive strength of the control concrete mixture at 28days. Bm 0.5% with lactate nutrition concrete mix had flexural strength value 162.74% of that of control concrete flexural strength at 28days. Enhancement of properties was due to calcite deposition on the bacteria cell surfaces within the pores. SEM imaging indicated the formation of calcite crystals in different shapes according to the added nutrients of bacterial concrete specimens.