熱干混砂漿夏季施工的工作性及性能優(yōu)化
發(fā)布時間:2018-07-07 23:03
本文選題:干混砂漿 + 高溫。 參考:《清華大學》2013年碩士論文
【摘要】:目前,普通干混砂漿行業(yè)普遍存在一些問題,如生產(chǎn)過程中的離析、砂源不好且質量波動大帶來的抹灰砂漿空鼓開裂、過分追求高保水率帶來的混凝土剪力墻抹灰空鼓開裂、烘干能力不足導致的砂漿過熱等。由于普通干混砂漿在國內絕大部分城市尚處于初級發(fā)展階段,生產(chǎn)量不大,尚未意識到熱砂漿這個問題,所以目前對熱砂漿問題研究較少。在以天然砂為主要砂源、普通砂漿發(fā)展比較成熟的城市如成都、常州等地,熱砂漿問題非常突出,尤其是在夏季。 熱砂漿存在著稠度損失大、外加劑部分或全部失效導致的保水率降低、收縮率大等影響施工效率和砂漿質量的問題。為解決這些問題,本論研究了溫度、相對濕度及各種外加劑組分對熱干混砂漿保水性、砂漿水分蒸發(fā)速率、水泥水化速率等性能的影響,發(fā)現(xiàn)溫度、相對濕度及外加劑組分均能影響熱砂漿性能。影響規(guī)律如下:溫度升高,水泥水化速度及砂漿中水分蒸發(fā)速度加快,砂漿稠度損失加快、保水率降低;相對濕度越小,砂漿中水分蒸發(fā)速度越快,砂漿稠度損失越快;HPMC能提高熱砂漿的保水率,延緩熱砂漿水泥水化,隨著摻量增加,保水率提高,緩凝效果增強,但不能抑制高溫下砂漿中水分蒸發(fā),,凝膠溫度較高的HPMC更適合用于熱砂漿;STPP能在一定程度上延緩水泥水化,降低砂漿的稠度損失,但不能有效抑制高溫下砂漿中水分蒸發(fā);重鈣粉在一定程度上不僅可以提高砂漿的保水率,增加28天抗壓強度,降低砂漿的收縮率,而且能夠抑制熱砂漿水分蒸發(fā)速率,從而降低砂漿2小時稠度損失,改善砂漿的工作性。 優(yōu)化外加劑是優(yōu)化熱干混砂漿工作性及其它性能的重要途徑,通過正交試驗得出當外加劑各組分配合比例為75HD100000S:PAV29:FDN-1:STPP:重鈣粉=0.3:2.0:2.0:0.3:10.0時,熱砂漿工作性能及其它性能均能得以改善和提高,并選取DM5砌筑砂漿和DP M5及DP M10抹灰砂漿對此配合比例進行了試驗室驗證。為驗證此配合比例的實用性,進行了工程應用檢驗,應用效果良好。
[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.
【學位授予單位】:清華大學
【學位級別】:碩士
【學位授予年份】:2013
【分類號】:TU578.1
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