A Study On Rational Proportion Of Hybrid Modified Water Resistant Mortar

In order to overcome the disadvantages of traditional historical building repair mortar, an experimental study into hybrid modified water resistant mortar was carried out by incorporating mineral admixture(fly ash, blast furnace slag, silica fume) and a polymer water repellent (Caltite). The impermeability and the acid resistance were expected to be improved significantly. Therefore, the life of mortar would be extended very much.In this thesis, compared with the portland-cement mortar, the influences of mineral admixture and Caltite on the physical properties (fluidity, bulkdensity), the mechanical properties(compress strength, flexural strength, shrinkage ratio) and the durability(water absorption, softening coefficient, wet-dry cycle, acid resistance)of the modified mortar were investigated. Together with the macro research, the micro structure of the different mortars were observed and analysed with FTIR, SEM and MIP in order to explain the modified mechanism of Caltite. A synthetical assessment was performed based on the macro and micro property tests.The test results show that optimum mix ratio of plasterer (masonry)waterproof mortar mix ratio is: (cement + fly ash + blast furnace slag + silica fume) : sand : water : FDN-5: defoamer : caltite = (0.75+0.15+0.1+0.05) : 2 : 0.34(0.32) : 0.01 : 0.002 : 7L/m3. Compared with traditional mortar, the hybrid modified mortar has much better mechanical properties, sulfuric resistance and durability. The impermeability cofficient of the modified plasterer (masonry) mortar is 48.2% (39.03%) higher than that of the control mortar.