机喷抹灰石膏的制备及其性能研究

发布时间：2018-03-06 11:12

本文选题：机喷抹灰石膏　切入点：缓凝剂　出处：《北京工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：机械喷涂抹灰石膏不仅迎合了当今绿色、环保的装修主题,而且改变了传统以水泥基为胶凝材料的习惯,克服了传统抹灰材料干缩性大、粘结力差引起的开裂、空鼓等质量通病,且可节约工程总造价、节约人工费,加快工程施工进度。机喷抹灰石膏代替石灰砂浆和水泥砂浆抹灰是建筑墙面装饰装修的一个发展趋势,对其性能影响因素的系统研究,具有重要理论意义和实用价值。试验选用降解聚酰胺经钙盐化而成的缓凝剂A、韩国生产的蛋白质类缓凝剂B、国内生产的蛋白质类碱性缓凝剂C,研究其对建筑石膏标准稠度用水量、凝结时间、抗折强度、抗压强度等指标的影响,并结合过饱和度分析、SEM形貌分析、压汞法孔结构分析、水化速率、水化放热等对其作用机理进行研究;针对不同粘度等级的缓溶型、速溶型保水剂HPMC对建筑石膏标准稠度用水量、保水率、抗折强度、抗压强度、拉伸粘结强度等性能的影响;用最少的原材料种类制备出了性能良好的机喷抹灰石膏,研究了水膏比、缓凝剂掺量、HPMC掺量、浆体搅拌速率、膏砂比对机喷抹灰石膏流变性能的影响。研究表明:(1)三种缓凝剂对建筑石膏标准稠度用水量影响程度由高到低的顺序为:B㧐C㧐A;三种缓凝剂缓凝效果由高到低的顺序为A㧐C㧐B;三种缓凝剂对建筑石膏强度破坏程度由高到低的顺序为B㧐C㧐A。低掺量0.02%~0.03%的缓凝剂A既可满足凝结时间要求又可最大限度的降低建筑石膏强度损失。(2)缓溶型HPMC较大程度的增大了建筑石膏标准稠度用水量,速溶型HPMC较大程度的提升了建筑石膏拉伸粘结强度,且对建筑石膏抗折强度和抗压强度破坏性较低,但保水效果不明显。100000Pa?s缓溶型HPMC综合性能较好,建议掺量为0.15%~0.2%。(3)将机喷抹灰石膏将凝结时间控制在1h左右,稠度控制在90mm~95mm,其工作性最佳。用浆体屈服应力、塑性黏度、触变性表征浆体流变性能,各影响因素对机喷抹灰石膏流变性能影响的顺序为水膏比HPMC掺量膏砂比浆体搅拌速率缓凝剂A掺量。(4)缓凝剂作用机理研究表明,缓凝剂降低了石膏浆体的过饱和度,过饱和度的降低带来石膏水化速率的减慢,使得结晶接触点少,晶体有充分的时间和空间生长,进而带来晶体结构的粗化、孔结构的恶化,最终导致石膏强度的降低。
[Abstract]:Mechanically sprayed plastering gypsum not only caters to the green and environment-friendly decoration theme, but also changes the tradition of using cement as cementing material, and overcomes the cracking caused by large dryness and poor adhesion of traditional plastering materials. The common quality problems such as empty drum and so on can save the total project cost, save labor cost and speed up the construction progress. It is a development trend of building wall decoration and decoration to replace lime mortar and cement mortar plastering with machine plastering plaster. A systematic study of the factors affecting its performance, It has important theoretical significance and practical value. The experiment selects the retarder A, protein retarder B produced in Korea and protein basic retarder Cproduced in our country, and studies its effect on building gypsum. Standard consistency water consumption, The effects of setting time, flexural strength and compressive strength on the mechanism were studied, including SEM morphology analysis of supersaturation, pore structure analysis by mercury injection method, hydration rate, hydration heat release and so on. The effects of HPMC on the standard consistency, water retention, flexural strength, compressive strength and tensile bond strength of gypsum were studied. With the least kinds of raw materials, a good performance plastering gypsum was prepared. The ratio of water to paste, the amount of retarder and HPMC, the mixing rate of slurry were studied. Effect of gypsum / sand ratio on rheological properties of plaster gypsum. The results show that the influence of three retarders on the standard consistency water consumption of building gypsum is in the order of: B? C? The order of retarding effect of three retarders from high to low is A? C? B; the order of strength failure of three retarders to gypsum from high to low is B? C? A. low content 0.02% retarder A can not only meet the setting time requirements, but also reduce the strength loss of building gypsum to the maximum extent.) the slow-soluble HPMC can increase the standard consistency water consumption of building gypsum to a large extent. The quick soluble HPMC can improve the tensile bond strength of building gypsum to a large extent, and the damage to the flexural strength and compressive strength of building gypsum is low, but the water retention effect is not obvious. It is suggested that the setting time and consistency of plastering gypsum should be controlled at about 1 h and 90 mm / 95 mm, respectively. The slurry yield stress, plastic viscosity and thixotropy are used to characterize the rheological properties of the slurry. The influence of various factors on the rheological properties of plaster gypsum is in the order of water / paste ratio, HPMC ratio, paste speed retarder A, and retarder A). The results show that the retarder can reduce the supersaturation of gypsum slurry, and the results show that the retarder reduces the supersaturation of gypsum slurry. The decrease of supersaturation will slow down the hydration rate of gypsum, make the crystal have less contact point, have enough time and space to grow, and then bring about the coarsening of crystal structure and the deterioration of pore structure, which will eventually lead to the decrease of gypsum strength.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ177.3

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