Properties Of GRC Modified By Three Dimensional Fabric And Polymer Emulsion

GRC(Glass fiber Reinforced Cement) is a type of cementitious composite material using glass fiber to reinforce cement mortar. The glass fiber in GRC will mainly enhance the mechanical properties and meanwhile improve the toughness of the cement matrix.Nowadays, there are some problems about cracking and durability with GRC for exterior wall. As a result, the mechanical properties, toughness and durability of GRC modified by 3D fabric(three dimensional glass fiber fabric) and PA(pure acrylic emulsion) are investigated systematically in the paper. There are three kinds of cement matrixes in this paper, they are CSA(calcium sulphoaluminate cement), OPC(ordinary Portland cement) and OPF(ordinary Portland cement with 50% fly ash).First of all, we investigate the effect of 3D fabric on the mechanical properties and toughness of GRC. The experimental results indicate that the LOP(limit of proportionality), MOR(modulus of rupture) and impact strength values are respectively bigger than 15.0MPa, 33.0MPa and 42.0k J/m2, and the GT(GRC toughness) value is above 34. While as for the double meshes reinforced GRC, its LOP, MOR and impact strength values have increased by 110%, 80% and 210%, and its GT value increases by 70%. This means that 3D fabric can greatly improve the mechanical properties and toughness of GRC.Then we investigate the effect of PA on the mechanical properties, toughness and durability of GRC. Results indicate that the best polymer content is at 9-12%. Compared with the control group without PA, the LOP and MOR values of modified GRC have increased by 80-105% and 50-80%. However, the impact strength value has decreased by 15-30%, and the GT value is above 10. Moreover, GRC modified by PA has better impermeability and anti-carbonation property than the control group, with the infiltration depth of about 30% and the carbonation depth of about 50-70% of the later.Finally, we investigate the effect of PA on the mechanical properties, toughness and durability of 3D fabric reinforced GRC. Results indicate that the mechanical properties and toughness all get better, with the LOP, MOR and impact strength values of respectively above 17.5MPa, 37.5MPa and 38.5 k J/m2, and the GT value is above 35. Besides, the retention ratio of LOP, MOR and impact strength are all around 95% after 25 freeze-thaw cycles and there are no delamination, cracking or peeling, which proves a good frost resistance. What is more, after exposed in 50℃ hot water for 180 days, the GRC made of CSA has the best durability. Its retention ratios of LOP and MOR are around 85% and the retention ratio of impact strength is about 80%.In summary, 3D fabric and PA can not only improve the mechanical properties and toughness of GRC, but also its durability. The 3D fabric reinforced GRC made of CSA modified by PA has the best mechanical properties, toughness and durability. Besides, connection is built between microstructure morphology and macroscopic properties through our observation and analysis of GRC microstructure and morphology utilizing mercury injection apparatus and SEM.