The bond and anti-abrasion performance of repair materials are the key factors for successful repair of hydraulic concrete. Acrylic acid emulsion (AAE) mortar, silica fume (SF) mortar, high strength (HS) mortar, polypropylene (PP) fiber mortar and basalt fiber (BF) mortar were prepared and their direct tensile bond strength, splitting tensile bond strength, abrasion resistance and SEM analysis of bond interface are studied in this paper. The results show that the highest direct tensile bond strength was recorded for fiber mortar. But compared to homogenous specimen’s tensile strength, AAE mortar showed the highest direct tensile bond strength. The anti-abrasion properties of repair mortars were tested with decreasing performance recorded in the following order: PP fiber mortar, SF mortar, BF mortar, HS mortar and AAE mortar. Compared with the HS mortar without fiber, the wear rate of PP fiber mortar was decreased by 29.2 % and the anti-abrasion strength was increased by 37.7%. This shows that adding fiber can greatly improve the anti-abrasion property. SEM analysis showed that addition of PP fiber and BF into repair mortar did not change the type of hydrates. The interface of AAE mortar was level and dense. The bond interface of SF mortar was uniform without big porosity. Addition of super plasticizer, the bond interface of HS mortar presented a large quantity of fibrous the CSH gel and less porosity which could improve the mortar bond effect effectively.
Treatment with nano-silica and bacteria to restore the reduced bond strength between concrete and repair mortar caused by aggressive removal techniques
