Authors: Baoguo Ma Hainan Li Junpeng Mei Xiangguo Li
Publish Date: 2017/02/12
Volume: 32, Issue: 1, Pages: 106-112
Abstract
The influences of different nano–SiO2 NS contents on the mechanical properties and rheological behavior of sulfoaluminate cement SAC based composite materials were studied Results show that with increasing content of NS the apparent viscosity and shearing strength of fresh paste gradually increase but the fluidity decreases With a dosage of 30 NS the tensile and flexural strengths of mortars at 56 days were increased by 870 and 846 respectively compared with that in the absence of NS indicating that the toughness of hardened mortars is significantly improved Besides the exothermic peaks of hydration are obviously increased and will earlier occur and the second and the third peaks appear 261 hours and 256 hours earlier respectively than that in the absence of NS and the hydration of SAC before 8 hours is accelerated The forming mechanism of strengths was revealed by scanning electron microscopy SEM hydration heat Xray diffraction XRD and derivative thermogravimetry DTG The microaggregate filling effect and nucleation effect at early age and weak pozzolanic effect at late age of NS make the microstructure more compact which obviously enhances the strength of SAC mortars
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