碱激发胶凝材料减缩及施工性能的研究

发布时间：2018-02-22 01:28

本文关键词： 固体硅酸钠碱矿渣凝材料减缩施工性能　出处：《苏州科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：碱矿渣胶凝材料是以碱作为激发剂激发具有潜在活性矿渣,是一种强度高,耐久性好,绿色,环保的建筑材料。发展至今,以NaOH和液体水玻璃激发效果最好,其中水玻璃效果更佳。但生产时由于是液态,需要额外添加,调节模数时需要额外加入NaOH,操作有潜在危险性。固体硅酸钠主要成分与液体水玻璃一致,可以跟矿渣一起研磨,搅拌,生产成为成品。使用时只需加水搅拌即可,方便使用。本文从碱矿渣胶凝材料基础性能、施工性能、收缩三个方面研究固体硅酸钠对矿渣激发效果。结果表明,两种激发剂对碱矿渣胶凝材料激发效果存在一定差异,同等水灰比下,激发剂为固体硅酸钠时,碱矿渣胶凝材料净浆,砂浆,混凝土的强度均比激发剂液体水玻璃为高。但固体硅酸钠激发碱矿渣胶凝材料同样具有高强度,且搅拌粘度降低,水化反应速率变慢,可用高。硝酸钡和硼砂-蔗糖缓凝剂对固体硅酸钠激发的碱矿渣胶凝材料具有良好的缓凝效果。硝酸钡掺量小,缓凝效果好;硼砂-蔗糖掺量大,缓凝效果最佳,初凝时间达到4h,但强度会严重降低,28d强度下降达到46%。萘系减水剂对碱矿渣胶凝材料有一定减水效果,与碱矿渣溶液中的吸附量呈高度线性相关关系,减水效果随着吸附量的变化而变化;萘系减水剂在碱矿渣中掺量大,会降低碱矿渣砂浆和混凝土的强度。矿物掺合料的掺入对碱矿渣砂浆、混凝土施工性能有一定影响。掺量8%-32%范围内,粉煤灰和偏高岭土掺量增加,碱矿渣砂浆的流动度降低,氧化镁和偏高岭土低掺时能增加砂浆的抗压强度;粉煤灰会提高碱矿渣混凝土的坍落度,矿物掺合料掺入会降对碱矿渣混凝土强度影响甚微。激发剂为固体硅酸钠,碱矿渣胶凝材料的化学收缩比激发剂为液体水玻璃小,硅酸盐水泥收缩类似;液体水玻璃碱矿渣混凝土干燥收缩比固体硅酸钠小;萘系减水剂会使碱矿渣胶凝材料的收缩增加;偏高岭土对抑制碱矿渣胶凝材料化学收缩效果最佳,28d收缩降低了27.9%;氧化镁对碱矿渣砂浆减缩效果最好,60d收缩降低39%,但氧化镁与反应较慢,早期减缩效果不佳;粉煤灰会增大碱矿渣混凝土干燥收缩,UEA对抑制碱矿渣混凝土收缩效果最佳,掺量为15%时,120d收缩降低了28%。
[Abstract]:Alkali slag cementitious material is a kind of building material with high strength, good durability, green and environmental protection, which is activated by alkali as activator. The effect of sodium silicate is better. However, because it is liquid in production, it is necessary to add additional NaOH to adjust the modulus. The operation is potentially dangerous. The main composition of sodium silicate is consistent with liquid water glass and can be ground together with slag. In this paper, the stimulation effect of solid sodium silicate on slag is studied from three aspects: basic properties, construction properties and shrinkage of alkali slag cementitious materials. There are some differences between the two activators for alkali slag cementitious materials. When the same water-cement ratio is used, when the activator is solid sodium silicate, the alkali slag cementitious material can be treated with pure mortar and mortar. The strength of concrete is higher than that of activator liquid water glass, but the solid sodium silicate activated alkali slag cementitious material also has high strength, and the agitation viscosity decreases, and the hydration reaction rate becomes slower. Barium nitrate and borax-sucrose retarder have good retarding effect on alkali slag cementitious material excited by solid sodium silicate. The initial setting time is 4 h, but the strength will be reduced to 46% in 28d. Naphthalene water reducer has a certain water reducing effect on alkali slag cementitious material, which has a high linear correlation with the adsorption capacity in alkali slag solution. The water reducing effect varies with the adsorption capacity, the strength of the alkali slag mortar and concrete will be reduced if the naphthalene superplasticizer is added to the alkali slag, the addition of mineral admixture can reduce the strength of the alkali slag mortar. The content of fly ash and metakaolin increases, the fluidity of alkali slag mortar decreases, and the compressive strength of mortar can be increased when the content of MgO and metakaolin is low. Fly ash can increase the slump of alkali slag concrete, and the addition of mineral admixture will have little effect on the strength of alkali slag concrete. The activator is solid sodium silicate, and the chemical shrinkage of alkali slag cementing material is smaller than that of activating agent liquid sodium silicate. The shrinkage of Portland cement is similar, the drying shrinkage of liquid sodium silicate slag concrete is smaller than that of solid sodium silicate, the shrinkage of alkali slag cementitious material is increased by naphthalene superplasticizer. The effect of metakaolin on inhibiting the chemical shrinkage of alkali slag cementitious material was the best in 28 days and that of magnesium oxide on alkali slag mortar was decreased by 27.9g in 28 days, and the shrinkage of alkali slag mortar by magnesium oxide was 39% lower than that of alkali slag mortar in 60 days, but the reaction of magnesium oxide was slow and the effect of early shrinkage reduction was not good. Fly ash can increase the drying shrinkage of alkali slag concrete. UEA has the best effect on inhibiting the shrinkage of alkali slag concrete.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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