In order to notably improve the mechanical properties and durability of low-grade cement-based material, superfine silica fume was used to modify the cement-based composite based on special perfomance and effects of nano powder. The mechanical performance and durability were investigated.Then the phase compositions,microstructure and morphologies of as-received cement-based composite were studied by X-ray Diffractometer、TGA-DTA and SEM. The results show that： the best formula of raw materials is 1:1:0.025:0.015, and hydration can be accelerated and increasing of hydration products is observed after modification. In the hardened cement matrix, microstructure is very compacted and C-S-H gel forms densed structure, so the structure defect is notably reduced. This means that both strength and durability of cement-based composite are notably improved by the addition of superfine silica fume.
Abstract: The fly ash and coal gangue were used as main raw materials to roast solid insulating brick.Lower than solid clay brick (300 °C) which belongs to low temperature roasting , roasting time cycle is 24 h ,the ratio of fly ash and coal gangue is 60% :35%. the B7 admixing expanded pearlite compressive strength is 30.25 MPa . Strength reach general clay brick MU30 high-class level .Thermal coefficient of conduction is 0.4 W/(m.K), lower than general clay brick thermal coefficient of conduction 0.78 W/(m.K); In addition , B7 XRD pattern has evident quartz、mullite diffraction character peak and TGA-DTA pattern between 900°C~1200°C, following temperature rise, green body heat-absorbing , begin melt 、glass reduction .The result is high in strengths . SEM scanning show : after being roasted in 950°C , globular solid glass bead 、pearlitic drusy pearlite 、flocculation aluminosilicate phase and so on , raw materials particle interstices were filled with viscous hyaline, so that B7 turned out high strengths . Acidproof、alkaliproof、freezing test and strengths results show: the lasting quality of solid insulating brick was best.
Abstract: The fly ash and coal gangue were used as main raw materials to roast solid insulating brick.Lower than solid clay brick (300 °C) which belongs to low temperature roasting , roasting time cycle is 24 h ,the ratio of fly ash and coal gangue is 60% :35%. the B7 admixing expanded pearlite compressive strength is 30.25 MPa . Strength reach general clay brick MU30 high-class level .Thermal coefficient of conduction is 0.4 W/(m.K), lower than general clay brick thermal coefficient of conduction 0.78 W/(m.K); In addition , B7 XRD pattern has evident quartz、mullite diffraction character peak and TGA-DTA pattern between 900°C~1200°C, following temperature rise, green body heat-absorbing , begin melt 、glass reduction .The result is high in strengths . SEM scanning show : after being roasted in 950°C , globular solid glass bead 、pearlitic drusy pearlite 、flocculation aluminosilicate phase and so on , raw materials particle interstices were filled with viscous hyaline, so that B7 turned out high strengths . Acidproof、alkaliproof、freezing test and strengths results show: the lasting quality of solid insulating brick was best.
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