本文選題：復配　切入點：早強　出處：《西安建筑科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：聚羧酸高性能減水劑作為第三代高性能減水劑,具有摻量低、減水率高、保坍性能好、有害物質(zhì)含量極低等綜合技術(shù)性能,但聚羧酸減水劑的獨特分子結(jié)構(gòu)特點會延緩水泥水化,影響混凝土早期強度發(fā)展,限制了在預制構(gòu)件等工程中的應用,采用復配的方法制備早強性能的聚羧酸減水劑,具有工藝簡單,易于控制的特點。本文將有機鹽、無機鹽等早強劑與陰離子型聚羧酸減水劑(PC-O)和兩性型聚羧酸減水劑(PC-E)分別進行復配,探究不同類型和不同摻量早強劑與兩種聚羧酸減水劑復配對膠砂及混凝土性能的影響。試驗不僅對其標養(yǎng)和蒸養(yǎng)條件下的性能進行研究,還采用直接測溫法和XRD技術(shù)研究了蒸養(yǎng)條件下不同早強劑與聚羧酸減水劑復配對水泥水化溫峰值、溫峰出現(xiàn)時間及Ca(OH)2生成量的影響規(guī)律,對復配早強型聚羧酸減水劑的作用機理進行了分析,論文主要研究內(nèi)容及結(jié)果如下:首先,對陰離子型和兩性型聚羧酸減水劑的性能進行對比,對比兩種聚羧酸減水劑不同摻量對流動性能、凝結(jié)時間和膠砂強度的影響規(guī)律,確定最佳復配摻量。結(jié)果表明:當陰離子型聚羧酸減水劑的摻量為0.34%和兩性型聚羧酸減水劑摻量為0.36%時,兩組水泥凈漿既有較好的流動度又有較小的經(jīng)時損失,而且初凝、終凝時間較短,膠砂1d抗壓強度也達到最大值。其次,使用早強劑(TEA、Li_2CO_3、Na_2SO_4)與PC-O進行復配,對比不同摻量早強劑與PC-O復配對標養(yǎng)和蒸養(yǎng)膠砂,蒸養(yǎng)混凝土強度的影響。結(jié)果表明:在標養(yǎng)條件下,復配早強型聚羧酸減水劑對膠砂早期強度的提高并沒有明顯效果,在80℃蒸養(yǎng)條件下,TEA摻量為0.06%、Li_2CO_3為0.06%、Na_2SO_4為0.6%時均有明顯早強效果。然后,使用早強劑(Na_2SO_4、NaNO_2、C_(16)H_(34)O)與PC-E進行復配,結(jié)果表明:在標養(yǎng)和50℃、80℃蒸養(yǎng)條件下,Na_2SO_4復配摻量為0.6%~0.8%、NaNO_2為0.6%~0.8%、C_(16)H_(34)O為0.03%~0.05%時,不僅早強效果顯著,而且后期強度也有明顯增強。特別是在80℃蒸養(yǎng)條件下,早期強度增強更為明顯,其順序為C_(16)H_(34)ONa_2SO_4NaNO_2。最后,通過對摻入早強劑與兩種不同品種聚羧酸減水劑復配凈漿溫度-時間曲線和水泥石XRD的分析可知,復配兩性型聚羧酸減水劑更能夠提高水泥水化溫升,縮短溫峰出現(xiàn)的時間,生成更多的Ca(OH)2,以及促進了C3S的早期水化,生成較多的C-S-H。
[Abstract]:Polycarboxylic acid high performance water reducer, as the third generation high performance water reducing agent, has comprehensive technical properties, such as low content, high water reducing rate, good collapsibility, very low content of harmful substances, etc. However, the unique molecular structure of polycarboxylic acid superplasticizer will delay cement hydration, affect the early strength development of concrete, and restrict the application in prefabricated components. In this paper, organic salts and inorganic salts were mixed with anionic polycarboxylic acid superplasticizer (PC-O) and amphoteric polycarboxylic acid superplasticizer (PC-E) respectively. The effects of different types and different contents of early strength agents and two kinds of polycarboxylic acid water reducer on the properties of cement sand and concrete were studied. The effects of different early strength agents and polycarboxylic acid superplasticizer on cement hydration temperature peak value, temperature peak time and Ca(OH)2 production were also studied by direct temperature measurement and XRD technique. In this paper, the mechanism of the compound early and strong polycarboxylic acid superplasticizer is analyzed. The main research contents and results are as follows: firstly, the performance of anionic polycarboxylic acid superplasticizer and amphoteric polycarboxylic acid superplasticizer is compared. The effects of two kinds of polycarboxylic acid superplasticizer on fluidity, setting time and cement sand strength were compared. The results show that when the amount of anionic polycarboxylic acid superplasticizer and amphoteric polycarboxylic acid superplasticizer is 0.34% and 0.36 respectively, the two groups of cement paste have both better fluidity and smaller meridional loss, and the initial setting is the same as that of anion polycarboxylic acid superplasticizer and amphoteric polycarboxylic acid superplasticizer. The final setting time was shorter, and the compressive strength of cement sand reached its maximum value in 1d. Secondly, PC-O was mixed with PC-O by using the early strength agent TEAS Li2COS3 / Na2SO4. The results show that under the standard condition, the composite of early strength polycarboxylic acid superplasticizer has no obvious effect on the early strength of cement sand. Under the condition of 80 鈩，

本文編號：1603050