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通过开展在不同龄期、不同环境湿度下玻璃纤维增强水泥(GRC)试件的抗折强度、抗压强度试验和基体pH值测定,研究了环境湿度对掺加粉煤灰和硅灰等活性矿物掺合料的GRC试件力学性能的影响。结果表明:环境湿度对GRC试件的抗折强度有重要影响,相对湿度越大,随着龄期增加,GRC试件抗折强度降低越严重;在温度60℃、相对湿度95%条件下,经过56d龄期后,掺有40%粉煤灰和10%硅灰的GRC试件抗折强度比未掺加粉煤灰和硅灰的GRC试件的抗折强度提高48.5%、抗压强度提高23.6%,GRC基体pH值降低6%。在相同的湿度条件下,掺有粉煤灰和硅灰试件的pH值在各个龄期都低于普通硅酸盐水泥试件,说明粉煤灰和硅灰的掺入能降低水泥水化液相的碱度,进而延缓了纤维受侵蚀的速度,显著改善了GRC试件的力学及耐久性能。通过对试验结果进行分析,利用MATLAB软件建立了GRC试件抗折强度和抗压强度与水泥砂浆基体pH值及时间的关系式。
Through the tests of flexural strength, compressive strength and substrate pH of glass fiber reinforced cement (GRC) specimens under different age and humidity, the effects of environmental humidity on the activity of fly ash and silica fume were studied. Effect of mineral admixtures on the mechanical properties of GRC specimens. The results showed that: the environmental humidity had an important influence on the flexural strength of GRC specimens. The greater the relative humidity, the more the GRC specimens degrade flexural strength with the increasing of age. Under the conditions of 60 ℃ and 95% RH, After 56d age, the flexural strength of GRC specimens with 40% fly ash and 10% silica fume increased 48.5% than that of GRC specimens without fly ash and silica fume, the compressive strength By 23.6%, the pH of GRC matrix decreased by 6%. Under the same humidity conditions, the pH values of fly ash and silica fume samples were lower than ordinary portland cement samples at all ages, indicating that the incorporation of fly ash and silica fume can reduce the hydration of cement The alkalinity of the liquid phase slowed down the erosion of the fiber and significantly improved the mechanical and durability properties of the GRC specimens. Through the analysis of test results, the relationship between the flexural strength and compressive strength of GRC specimens and the pH and time of cement mortar matrix was established by MATLAB software.