机制砂预拌砂浆生产质量控制研究

发布时间：2018-04-22 13:44

  本文选题：机制砂 + 预拌砂浆　； 参考：《重庆大学》2015年硕士论文

【摘要】：随着我国城市化进程的不断深入,预拌砂浆的市场化进程稳步向全国推进。在市售预拌砂浆中,全机制砂预拌砂浆的市场份额越来越高。然而,机制砂本身受限于母岩成分、制砂工艺等因素,导致其性能不稳定。不仅如此,现有的预拌砂浆生产工艺和配合比设计并未考虑到施工工艺和环境因素对其性能的影响,并且相关标准中并未对砂浆在施工现场的存放时间进行规范。因此砂浆在施工现场的存放时间过长、加水重塑现象仍十分普遍,严重的影响抹灰砂浆的质量。本论文首先对机制砂级配和石粉含量对预拌砂浆工作性的影响进行了实验研究,其次研究了外加剂、施工因素对机制砂预拌砂浆工作性和力学性能的影响,并通过对砂浆稠度变化的数值进行了回归拟合,最终获得稠度变化方程。通过将获得的实验结果和拟合方程进行统计,设计出一个机制砂预拌砂浆生产软件,用以判断和预测砂浆在各种情况下的稠度发展规律和开放时间。实验得出的主要研究结论如下:紧密堆积状态下的机制砂级配是最合理的。0.075~0.15mm的细粉颗粒应当被包含在石粉中,石粉含量的限值应当为10%,石粉以及0.075~0.15mm的细颗粒总量应在15%~20%区间内。增稠保水剂掺量在0.14~0.21‰之间时砂浆初始稠度及粘性适宜用作抹灰砂浆。掺量为0.43~0.64‰的引气剂可有效的降低砂浆容重并提高砂浆初始稠度。葡萄糖酸钠掺量为0.17‰~0.26‰时砂浆开放时间及初始稠度较为合适。粉煤灰对于砂浆的主要作用在于其对于砂浆工作性的提升,对比内掺和粉代砂两种掺入方式,后者对体系提升作用更为明显。各外加剂对开放时间调整能力排序如下:缓凝剂≥引气剂增稠保水剂。温度高于35℃的砂浆开放时间将缩短一半以上。重塑可以暂时性地提升砂浆的稠度,但重塑后砂浆工作性损失会显著地加快,且其抗压会损失30%以上,抗折强度会损失70%以上,且其收缩率会显著增大。机制砂预拌砂浆稠度变化拟合方程可以较好地描述指定原材料条件下的砂浆的稠度变化规律。该方程主要描述稠度变化的早期过程,并通过对于各因素对初始稠度C0和稠度下降速率R的影响来计算砂浆的开放时间最终获得的拟合方程的相关系数均在0.92以上,准确性较高。基于前文的实验结果,机制砂预拌砂浆生产过程辅助软件设计将整个砂浆生产过程分为三个过程,机制砂生产过程、开放时间设计调整过程、砂浆强度复核,配合比输出过程。综上所述,相比较混凝土,由于预拌砂浆适用范围较为固定,且制备工艺中影响因素较少,因此在限定的条件下定量的对机制砂预拌砂浆生产进行计算可预判变得可能,同时同时可以为机制砂预拌砂浆生产质量控制提供依据。
[Abstract]:With the development of urbanization in China, the marketization of ready-mixed mortar is advancing steadily to the whole country. In the market ready-mixed mortar, the market share of full-machined sand ready-mixed mortar is higher and higher. However, the mechanism sand itself is limited by the composition of parent rock, sand making process and other factors, which lead to the instability of its performance. Moreover, the existing production process and mix ratio design of ready-mixed mortar do not take into account the influence of construction technology and environmental factors on its performance, and the storage time of mortar in construction site is not standardized in relevant standards. Therefore, the storage time of mortar in the construction site is too long, and the phenomenon of water remolding is still very common, which seriously affects the quality of plastering mortar. In this paper, the effects of the gradation of machine-made sand and the content of stone powder on the workability of ready-mixed mortar are studied experimentally, and then the effects of admixture and construction factors on the workability and mechanical properties of machine-made mortar are studied. Finally, the equation of consistency change is obtained by regression fitting to the change of mortar consistency. Through the statistics of the experimental results and the fitting equation, a software for the production of machine-made sand ready-mixed mortar is designed to judge and predict the regularity of consistency development and the opening time of mortar under various conditions. The main conclusions of the experiment are as follows: the mechanism sand gradation is the most reasonable. 0.075 ~ 0.15mm fine particles should be included in stone powder, the limit value of stone powder content should be 10, and the total fine particles of stone powder and 0.075~0.15mm should be within the range of 15 ~ 20%. The initial consistency and viscosity of mortar are suitable for plastering mortar when the content of thickening water absorbent is 0.14 ~ 0.21 鈥，

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