玻纤、矿纤对钢渣/矿渣复合胶凝材料强度和膨胀性的影响

Effect of inorganic fibers on the strength and volume expansion of steel slag-blast furnace slag-cement cementitious composites

研究了玻纤、矿纤分别掺入钢渣/矿渣复合胶凝材料时对胶砂强度的影响,通过沸煮和压蒸试验研究两种纤维对胶凝材料体积膨胀的影响,通过SEM观察纤维与基体的界面粘结情况。强度实验结果表明,玻纤掺量(质量分数)不高于0.3%时,胶砂试件各龄期强度随着掺量的增加而提高,掺量高于0.3%,胶砂试件强度损失大;矿纤掺量对试件早期强度影响不大,后期抗压强度随掺量的增加持续下降,后期抗折强度先下降后上升。沸煮和压蒸试验结果表明,玻纤掺量0.3%的压蒸试件比不掺纤维时压蒸膨胀率下降26.60%,矿纤掺量0.3%的压蒸试件比不掺纤维时压蒸膨胀率下降29.36%。SEM结果显示,水化早期纤维表面附着少量C—S—H凝胶,纤维与基体相互分离,水化后期,纤维表面生长Ca(OH)2晶体,纤维与基体粘结紧密。

The effect of glass fiber or mineral fiber on the mechanical properties of basic oxygen furnace steel slaggranulated blast furnace slag cementitious composites has been studied in this paper.The volume expansion of the cementitious composites was measured by boiling and autoclave tests.In addition,the distribution,as well as the interfacial adhesion of fibers in the paste,was observed by SEM.The results showed that the strength of cementitious composite mortars initially increased increasing amount of glass fiber,but decreased when the dosage exceeded 0.3%.The content of mineral fiber had little effect on the strength of mortars in the early curing stage.However,the late compressive strength of the mortar decreased,and the flexural strength initially increased and then decreased with increasing dosoge of mineral fiber.According to the autoclave tests,the expansion rate decreased by26.60% after adding 0.3% glass fiber,and decreased by 29.36% after adding 0.3% mineral fiber.SEM results showed that fibers were separate from the hydration products in the early curing stages,but became well connected at late curing stages.In addition,calcium hydroxide was produced on the surface of the fibers.The adhesion of mineral fiber with the paste was better than that of glass fiber.