本文選題：混凝土 + 防凍劑　； 參考：《遼寧工程技術大學》2014年碩士論文

【摘要】：高緯度季凍區(qū)冬季時間長、氣溫低,混凝土的應用受到限制。為保證低溫季節(jié)混凝土順利施工,摻加混凝土防凍劑成為一個較為方便和經(jīng)濟的手段。但目前防凍劑多為復合型防凍劑,成分復雜,難于清楚了解防凍劑對于混凝土性能的影響,嚴重影響產(chǎn)品的應用與推廣。針對目前防凍劑應用混亂的情況,系統(tǒng)研究各防凍組分對混凝土性能的影響規(guī)律,揭示防凍組分的影響機理,為季凍區(qū)混凝土防凍劑的應用提供技術參考。首先討論了不同防凍組分對混凝工作性、力學性能與抗凍融耐久性的影響。結果表明：CaCl_2使初始坍落度減小,坍落度損失增大。Ca(NO_2)_2、Ca(NO_3)_2對初始坍落度有提高,但坍落度損失增大。乙二醇提高了初始坍落度,坍落度損失也減小。CaCl_2、Ca(NO_2)_2、 Ca(NO_3)_2、乙二醇均能起到一定的防凍效果,-10℃時,防凍效果對比有CaCl_2Ca(NO_3)_2乙二醇Ca(NO_2)_2。隨著CaCl_2、Ca(NO_2)_2摻量的增加,混凝土抗凍性能明顯減弱。乙二醇在較低摻量時,能提高混凝土的抗凍性能。其次通過研究防凍組分對摻減水劑混凝土工作性的影響,結果顯示,防凍組分對減水劑的性能影響不大。其影響主要表現(xiàn)在摻減水劑混凝土坍落度損失增大。接著建立了水泥稀漿搖泡中的氣泡指數(shù)衰減模型,指數(shù)衰減模型能夠較好的擬合氣泡體積隨時間的變化規(guī)律,其參數(shù)能夠表征不同引氣劑的特征參數(shù)。應用此模型研究了防凍組分對兩種不同引氣劑氣泡穩(wěn)定性的影響,并測定了混凝土拌合物含氣量。結果表明,對于皂苷類引氣劑,CaCl_2降低了氣泡穩(wěn)定性和混凝土拌合物含氣量,Ca(NO_2)_2、Ca(NO_3)_2降低了溶液的起泡能力而使含氣量也減少。乙二醇對泡沫的穩(wěn)定性有所提高,但起泡能力顯著下降,新拌混凝土含氣量也降低。對于苯磺酸鹽類引氣劑,CaCl_2使其氣泡能力下降,Ca(NO_2)_2則主要降低了泡沫的穩(wěn)定性,Ca(NO_3)_2不利作用不顯著,但摻三種鹽類混凝土拌合物含氣量均降低。乙二醇則提高了氣泡穩(wěn)定性與新拌混凝土含氣量。最后通過響應曲面法研究防凍劑各組分間配比的確定方法,結果顯示,響應曲面法回歸方程能較好預測混凝土負溫強度、坍落度、含氣量隨各參數(shù)的變化規(guī)律。最佳配比為：硝酸鈣摻量為4.79%,減水劑為0.21%,引氣劑為0.31%。實驗結果與預測值相差很小,表明響應曲面法能夠優(yōu)化防凍劑配比。
[Abstract]:The application of concrete is limited because of long winter time and low temperature in high latitude seasonal freezing area. In order to ensure the smooth construction of concrete in low temperature season, adding concrete antifreeze has become a more convenient and economical means. But at present, the antifreeze is mostly compound antifreeze, the composition is complex, it is difficult to understand clearly the influence of antifreeze on concrete performance, which seriously affects the application and popularization of the product. In view of the confusion in the application of antifreeze agents at present, the effects of various antifreeze components on the performance of concrete are systematically studied, and the influence mechanism of antifreeze components is revealed, which provides a technical reference for the application of antifreeze agents in seasonal freezing areas. The effects of different antifreezing components on coagulation performance, mechanical properties and freeze-thaw resistance durability were discussed. The results show that the initial slump decreases and the slump loss increases. Ethylene glycol increases the initial slump and reduces the slump loss. CaCl _ 2CaN _ (2) C _ (2) C _ (2) C _ (2), CaNO3 / T _ (2), ethylene glycol can all play a certain antifreeze effect at -10 鈩，

本文編號：1973739