废弃阴极射线管玻璃砂对砂浆性能的影响

Effect of Cathode Ray Tubes Glass Sand as Fine Aggregate on Properties of Mortar

废弃阴极射线管(cathode ray tubes,CRT)玻璃因其含有有害物质铅而导致严重环境问题,为此,使用粉煤灰、磨细矿渣作为矿物掺合料,研究了磨细阴极射线管玻璃(ground cathode ray tube glass,MG)取代0、30%、60%、100%(质量分数,下同)河砂细骨料时砂浆新拌性能、力学性能、干缩性能、碱骨料反应(alkali-silica reaction,ASR)膨胀性能、金属铅浸出值。结果表明:随着MG取代比例从0变化到100%,砂浆初始流动度与容重不段增加,硬化砂浆抗压强度、抗折强度和静弹性模量、干缩性能先增加后逐渐减小;MG取代比例为60%时,砂浆具有较高力学性能和较大干缩值;砂浆ASR膨胀值和硬化砂浆金属铅浸出值随MG取代比例增加而增加,但仍在安全范围内;掺加矿物掺合料的MG砂浆作为循环材料可用于干燥环境下的建筑砂浆。

The discarded cathode ray tubes glass represents an environmental problem due to the high content of lead. In this paper, fly ash and ground granulated blast furnace slag were used as mineral admixtures, the fresh, mechanical properties, the drying shrinkage, alkali-silica reaction （ASR） expansion and lead leaching properties of mortar with ground cathode ray tube glass sand （MG） fine aggregate at replacement levels of 0, 30%, 60% and 100% were investigated. The results show that the initial slump flow diame- ter and wet density of fresh mortar increase with the MG glass replacement level from 0 to 100%, the compressive strength, the flex- ural strength and static modulus of elasticity and the drying shrinkage values of mortar increase at the initial stages and trend towards the gradual decrease. The mortar with MG glass sand of 60% had higher mechanical properties and larger drying shrinkage values. The ASR expansion and the leaching value of lead in mortar increased with MG replacement levels from 0% to 100%. However, the ASR expansion and the leaching value of lead were on the safety range. The mortar with MG glass by adding mineral admixture could be used as a recycled material for the construction material in dry environments.