热干混砂浆夏季施工的工作性及性能优化

发布时间：2018-07-07 23:03

本文选题：干混砂浆 + 高温　；参考：《清华大学》2013年硕士论文

【摘要】：目前，普通干混砂浆行业普遍存在一些问题，如生产过程中的离析、砂源不好且质量波动大带来的抹灰砂浆空鼓开裂、过分追求高保水率带来的混凝土剪力墙抹灰空鼓开裂、烘干能力不足导致的砂浆过热等。由于普通干混砂浆在国内绝大部分城市尚处于初级发展阶段，生产量不大，尚未意识到热砂浆这个问题，所以目前对热砂浆问题研究较少。在以天然砂为主要砂源、普通砂浆发展比较成熟的城市如成都、常州等地，热砂浆问题非常突出，尤其是在夏季。热砂浆存在着稠度损失大、外加剂部分或全部失效导致的保水率降低、收缩率大等影响施工效率和砂浆质量的问题。为解决这些问题，本论研究了温度、相对湿度及各种外加剂组分对热干混砂浆保水性、砂浆水分蒸发速率、水泥水化速率等性能的影响，发现温度、相对湿度及外加剂组分均能影响热砂浆性能。影响规律如下：温度升高，水泥水化速度及砂浆中水分蒸发速度加快，砂浆稠度损失加快、保水率降低；相对湿度越小，砂浆中水分蒸发速度越快，砂浆稠度损失越快；HPMC能提高热砂浆的保水率，延缓热砂浆水泥水化，随着掺量增加，保水率提高，缓凝效果增强，但不能抑制高温下砂浆中水分蒸发，，凝胶温度较高的HPMC更适合用于热砂浆；STPP能在一定程度上延缓水泥水化，降低砂浆的稠度损失，但不能有效抑制高温下砂浆中水分蒸发；重钙粉在一定程度上不仅可以提高砂浆的保水率，增加28天抗压强度，降低砂浆的收缩率，而且能够抑制热砂浆水分蒸发速率，从而降低砂浆2小时稠度损失，改善砂浆的工作性。优化外加剂是优化热干混砂浆工作性及其它性能的重要途径，通过正交试验得出当外加剂各组分配合比例为75HD100000S：PAV29：FDN-1：STPP：重钙粉=0.3：2.0：2.0：0.3：10.0时，热砂浆工作性能及其它性能均能得以改善和提高，并选取DM5砌筑砂浆和DP M5及DP M10抹灰砂浆对此配合比例进行了试验室验证。为验证此配合比例的实用性，进行了工程应用检验，应用效果良好。
[Abstract]:At present, there are some problems in ordinary dry mixing mortar industry, such as segregation in production process, cracking of plastering mortar with poor sand source and great fluctuation of quality, excessive pursuit of concrete shear wall plastering crack caused by high water retention rate. Overheating of mortar caused by insufficient drying capacity. Due to the fact that ordinary dry mixed mortar is still in the primary stage of development in most cities in China, the production is not large and the problem of hot mortar has not been realized, so there is little research on hot mortar at present. In cities where natural sand is the main source and the development of ordinary mortar is relatively mature, such as Chengdu and Changzhou, the problem of hot mortar is very serious, especially in summer. Hot mortar has some problems such as large loss of consistency, decrease of water retention rate caused by partial or total failure of admixture, and large shrinkage rate, which affect construction efficiency and mortar quality. In order to solve these problems, the effects of temperature, relative humidity and various admixtures on the properties of hot and dry mortar, such as water retention, moisture evaporation rate and cement hydration rate, were studied. Relative humidity and admixture can affect the properties of hot mortar. The influencing rules are as follows: with the increase of temperature, the hydration rate of cement and the evaporation speed of water in mortar are accelerated, the loss of consistency of mortar is accelerated, the water retention rate is decreased, the less relative humidity, the faster the evaporation speed of moisture in mortar, the faster the loss of consistency of mortar; HPMC can improve the water retention rate of hot mortar and delay the hydration of hot mortar cement. With the increase of the content of HPMC, the water retention rate increases and the retarding effect is enhanced, but it can not restrain the evaporation of water in the mortar at high temperature, and the HPMC with higher gel temperature is more suitable for hot mortar. STPP can delay cement hydration to some extent and reduce the loss of mortar consistency, but it can not effectively restrain the evaporation of water in mortar at high temperature. To some extent, heavy calcium powder can not only increase the water retention rate of mortar, but also increase the compressive strength of 28 days. The shrinkage of mortar can be reduced, and the evaporation rate of water can be inhibited, thus reducing the loss of consistency for 2 hours and improving the workability of mortar. Optimization of admixture is an important way to optimize the workability and other properties of hot and dry mixed mortar. When the proportion of admixture components is 75HD100000S: PAV29: FDN-1: STPP: heavy calcium powder = 0.3: 2.0: 2.0: 2.0: 0.3: 10.0. The performance of hot mortar and other properties can be improved and improved. The proportion of DM5 masonry mortar and DP M5 and DP M10 plastering mortar is tested in laboratory. In order to verify the practicability of this proportion, the engineering application test is carried out, and the application effect is good.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU578.1

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