硅灰与氧化石墨烯对硬化水泥浆体的复合增强效应

Compound Enhancement Effect of Silica Fume and Graphene Oxide on Hardened Cement Paste

研究了硅灰与氧化石墨烯复掺时对硬化水泥浆体力学性能的影响.分别进行了普通水泥浆体、内掺质量分数10%的硅灰水泥、外掺质量分数0.8%的氧化石墨烯复合聚羧酸减水剂(GOPCs)水泥浆体以及同时内掺硅灰与外掺GOPCs的水泥浆体的配制.对4种硬化水泥浆体的抗折强度、抗压强度以及90 d龄期孔隙率进行了测定,同时采用X射线衍射仪及扫描电子显微镜对水泥水化产物进行分析,并将4种样品的力学性能进行比较.结果表明,当掺10%硅灰时,硬化水泥浆体90 d抗压强度比空白样提高了3.6%,抗折强度提高了9.6%;当只使用氧化石墨烯复合聚羧酸减水剂而不掺硅灰时,抗压强度提高了11.9%,抗折强度提高了15.3%;当硅灰与氧化石墨烯复掺时,抗压强度提高了22.7%,抗折强度提高了38.6%.孔隙率的变化以及XRD、SEM分析证实了这一结果.因此,硅灰与氧化石墨烯复合聚羧酸减水剂对硬化水泥浆体具有复合增强作用.

The influences of silica fume and graphene oxide on the mechanical property of hardened cement paste were investigated. First, the ordinary cement pastes were prepared. Then the cement pastes were prepared using 10% mass fraction of silica fume, 0.8% mass fraction of graphene oxide/polycarboxylate superplasticizer （GOPCs） and silica fume/GOPCs respectively. The flexural strength, compressive strength, porosity of the samples have been tested on the 90th day. The hydration products of the samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results show that the compressive strength and flexural strength of hardened cement paste with silica fume, GOPCs and fume/GOPCs composite respectively increase by 3.6% and 9.6%, 11.9% and 15.3%, and 22.7% and 38.6% compared with those of the ordinary hardened cement paste. The results were demonstrated by the data of porosity test, XRD and SEM images. Therefore, silica fume and GOPCs can enhance the mechanical property of hardened cement paste with a compound effect.