Water proofing performance assessment of hydrophobic agent-based Portland cement concrete: A multi-dimensional experiment approach

Heavy rainfall led to excessive water infiltration and saturation in the concrete surfaces, resulting the dampness. This can adversely affect the aesthetical view, durability and strength of the concrete over time. However, hydrophobic cement is a specialized type of cement that has been developed to exhibit resistance to water penetration in the cement composite, which enhance the durability of concrete structure. In this research, hydrophobic Portland cement concrete (HPCC) specimens were assessed considering the mechanical strength properties, water absorption by different methods, and microscopic observations of hydration products. It was revealed that the compressive strength (CS) of HPCC concrete achieved around 28.7 MPa and 35.6 MPa at 7d and 28d, respectively having water to cement (W/C) proportion 0.45. The splitting tensile strength of HPCC samples having W/C 0.45 also found around 1.98 MPa and 2.43 MPa at 7d and 28d, respectively which values were higher as compared to control OPC specimens. In addition, HPCC concrete specimens showed capillary water absorption at 90d for 1D, 4D and 6D about 0.25 %, 0.36 %, and 0.39 %, respectively which was lower than that of PCC concrete samples. Moreover, the HPCC concrete plate specimens shown significantly lower water penetration by static vertical water pressure, for example concrete plate having 100 mm thickness presented around 2.6 mm water absorption depth at 90days. Furthermore, very few micro-pores were observed by SEM (scanning electron microscopy) in the microstructures of HPCC, whereas micro-cracks were not visible in the focus area. However, the findings might be applied in the construction sectors to protect the exterior building walls, roof floor slabs and plastering the concrete surfaces from dampness.