Using nonionic paraffin emulsion to make waterproof engineered cementitious composites: mechanical properties and hydrophobic performance

The excellent cracking control characteristics and high ductility of engineered cementitious composites (ECC) make it a promising research prospect as a waterproof material. In order to design an ECC with excellent waterproof performance and good mechanical properties, nonionic paraffin emulsion (NPE) was used to modify ECC. The influence of NPE on the mechanical performance and water-repellent characteristics of ECC was explored experimentally. The results show that NPE significantly improves the hydrophobic performance without significantly reducing the mechanical properties of ECC. The capillary water absorption coefficient of ECC decreases, and the permeability resistance increases obviously with the increasing of NPE content. Meanwhile, the tensile strain capacity is always greater than 6%. When the NPE content is higher than 1%, the water contact angle of ECC is larger than 90°, indicating that the material exhibits good hydrophobicity. This study shows that NPE is an excellent admixture to improve the impermeability of ECC.