双壳层结构氯离子结合陶砂对海砂砂浆性能的影响

Add to Favorite Effect of chloride ion bonded ceramic sand with bishell structure on the properties of sea sand mortar

为控制混凝土内源型氯离子的危害,对核壳结构氯离子结合陶砂进行了研究,采用掺纳米二氧化硅(NS)水泥浆对核壳结构陶砂进行包裹,形成双壳层结构氯离子结合陶砂,并对其控制陶砂中结合的氯离子向外迁移的作用进行了研究。首先制备了以Fe_(2)O_(3)、Ca(OH)_(2)和Al_(2)O_(3)为芯料,赤泥、粉煤灰、黏土、石英为壳料,通过1200℃、1 h烧制而成的陶砂(简称CAF陶砂),当Fe_(2)O_(3)等摩尔取代1%Al_(2)O_(3)的CAF陶砂(简称CAF1陶砂)在氯盐溶液中浸泡56 d时,氯离子结合量达到172.75 mg/g。将1%NS取代率的水泥浆包裹CAF1陶砂表面形成双壳层陶砂,按20%掺入到未洗海砂砂浆中,28 d时,抗渗强度为0.3 MPa。砂浆中氯离子含量随离陶砂颗粒距离增大而减少,证明海砂中的氯离子前期被陶砂结合,并较为稳定地固定于陶砂中。

In order to control the harm of internal chloride ions in concrete,this paper studies the core-shell structure chloride ion bonded ceramic sand,and uses nano-silica(NS)cement slurry to wrap core-shell structure ceramic sand to form doubleshell structure chloride ion bonded ceramic sand,and studies its effect on controlling the outward migration of bonded chloride ions in the ceramic sand.Firstly,Fe_(2)O_(3),Ca(OH)_(2) and Al_(2)O_(3)were prepared as the core material,red mud,fly ash,clay and quartz as the shell material,and the ceramic sand(referred to as CAF ceramic sand)was fired at 1200℃and 1 h.When CAF ceramic sand(referred to as CAF1 ceramic sand)with 1%Fe_(2)O_(3)equal molar substitution for Al_(2)O_(3)was soaked in chlorine salt solution for 56d,the chloride ion binding amount reached 172.75 mg/g.Subsequently,the surface of CAF1 ceramic sand was coated with cement slurry containing 1%NS to form double shell ceramic sand,which was incorporated into unwashed sea sand mortar at 20%,compressive strength and impermeability of the mortar are 27.72 MPa and 0.3 MPa at 28 d.Chloride ion was found to be concentrated in the sand with its content deceasing with the distance from the sand,which proves that the chloride ion in the sea sand is bound by the sand in the early stage,and stably fixed in the sand later.