粒化高炉矿渣代砂地聚合物砂浆的强度特性及微观分析

Strength Characteristics and Microscopic Analysis of Geopolymer Mortar from Granulated Blast Furnace Slag

为研究粒化高炉矿渣地聚合物砂浆的强度特性及孔隙结构特征,采用不同掺量(0%、30%、50%、70%、100%)的粒化高炉矿渣,测试了不同龄期(3、7、28 d)地聚合物砂浆的抗压强度、抗折强度和劈裂抗拉强度等力学性能,分析不同代砂率砂浆的孔隙结构特征,并采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和扫描电镜(SEM)对其微观结构特征进行分析。结果表明,粒化高炉矿渣代砂地聚合物砂浆早期阶段的强度小于全河砂组,但其7~28 d的抗压强度增长速率大于全河砂组;相同养护龄期30%代砂率的地聚合物砂浆的气泡间距系数和孔隙率小,平均弦长大,内部结构更致密。XRD、FTIR和SEM结果显示,粒化高炉矿渣的掺加并未改变晶相结构的种类,随代砂率的提高,900~1200 cm^(-1)波数内,Si(Al)-O结构增多,C-(A)-S-H衍射峰逐渐增强,粒化高炉矿渣的掺加优化了内部孔隙结构,改善界面过渡区域的缺陷。综合考虑,30%代砂率其内部结构更为密实,表现出较高的强度特性。

In order to study the strength characteristics and pore structure characteristics of grained-blast furnace slag geoppolymer mortar,the grained-blast furnace slag with different contents(0%,30%,50%,70%,100%)were used to test the mechanical properties of geoppolymer mortar under different ages(3 d,7 d,28 d),such as compressive strength,flexural strength and splitting tensile strength.The pore structure characteristics of mortar under different sand generation rates were compared and analyzed.At the same time,X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM)were used to analyze the microstructure.The results showed that the strength of pelletized blast-furnace slag replaced polymer mortar in early stage was lower than that of the whole Hesha Group,but the compressive strength growth rate of the slurry from 7 to 28 days was higher than that of the whole Hesha group.Under the same curing age,the geopolymer mortar with 30%replacement sand rate had smaller bubble spacing coefficient and porosity,average string length and denser internal structure.XRD,FTIR and SEM results showed that the addition of granulated blast furnace slag did not change the type of crystal phase structure.With the increase of sand rate,the Si(Al)-O structure increased in the range of 900-1200 cm^(-1) wave number,and the C-(A)-S-H diffraction peak gradually increased.The addition of granulated blast furnace slag optimized the internal pore structure and the defects in the transition area of the interface were improved,and the internal structure was denser,showing higher strength characteristics under the comprehensive consideration of 30%sand replacement rate.