Preparation and properties of integrally hydrophobic self-compacting rubberized concrete

Brittleness and water invasion are critical reasons for the deterioration and failure of ordinary self-compacting concrete (SCC). To enhance the deformability and water repellency of SCC, integrally hydrophobic self compacting rubberized concrete (HSCRC) was prepared by adding crumb rubber (CR) and a hydrophobic agent (HA) into ordinary SCC. Furthermore, the combined effect of CR and HA on the fresh properties, hydrophobicity and mechanical properties of HSCRC were comprehensively studied. The results showed that the addition of CR resulted in a decline in the flowability, filling ability and passing ability and an enhancement in the viscosity and anti-segregation properties. However, the effect of adding HA on the fresh properties was opposite to that of adding CR. The surfaces of the samples mixed with the HA obtained contact angles greater than 130, and the 48-hour capillary water absorption and the 48-hour immersion water absorption of these samples were significantly reduced. Moreover, the compressive strength, splitting tensile strength, axial compressive strength and elastic modulus of the concrete samples decreased gradually with the increase of CR and HA content. Multiple regression models between different mechanical properties and CR and HA contents, as well as the conversion formulas between different mechanical properties, were obtained.