【摘要】：隨著我國大規(guī)模基礎(chǔ)工程設(shè)施的建設(shè)，天然砂資源日趨緊張、供需矛盾日益尖銳，，機(jī)制砂作為混凝土和砂漿的常規(guī)原材料而加以利用已成大勢(shì)所趨。但是，現(xiàn)行《建筑用砂》(GB/T14684-2011)規(guī)范嚴(yán)格限制了機(jī)制砂中的石粉含量，使得采用除塵或水洗方法生產(chǎn)的機(jī)制砂因顆粒多棱角、表面粗糙、自身滾動(dòng)能力差而大大降低自身流動(dòng)性，用于配制水泥砂漿容易出現(xiàn)嚴(yán)重泌水、黏聚性差等問題，因此需要研究合理增大機(jī)制砂中的石粉含量以改善水泥砂漿的工作性能。同時(shí)，采用機(jī)制砂配制的水泥砂漿還存在早期干縮大、易開裂等問題，需研究采用聚丙烯纖維對(duì)其進(jìn)行改性。目前，利用聚丙烯纖維改善天然砂水泥砂漿工作性能的研究比較深刻全面，而利用聚丙烯纖維改善機(jī)制砂水泥砂漿方面的研究還相對(duì)較少。而關(guān)于機(jī)制砂及所含石粉對(duì)水泥砂漿性能的影響研究多集中在單一強(qiáng)度等級(jí)下進(jìn)行，沒有考慮水泥用量對(duì)石粉摻量的影響，因而得出的結(jié)論各不相同。另外，機(jī)制砂中石粉含量對(duì)水泥砂漿用水量的影響只是定性的進(jìn)行描述，而缺乏定量分析�；诖吮疚闹饕獓@M5、M10、M15、M20四個(gè)強(qiáng)度等級(jí)水泥砂漿做了以下幾個(gè)方面的工作： 1)通過試拌尋找機(jī)制砂水泥砂漿用水量隨石粉含量的變化規(guī)律，并提出定量化的計(jì)算方法。 2)在保證水泥砂漿工作性能的基礎(chǔ)上，研究了機(jī)制砂中石粉含量為0、7.9%、10%、15%、20%、25%、30%時(shí)水泥砂漿質(zhì)量密度、抗壓、抗折、干縮、抗裂性能的變化規(guī)律。 3)在最佳石粉含量的基礎(chǔ)上，通過外摻不同長度（6mm、12mm、18mm)和不同摻量（0.6kg/m3、0.8kg/m3、1.0kg/m3、1.2kg/m3）的聚丙烯纖維，研究了聚丙烯纖維摻量和長度對(duì)機(jī)制砂水泥砂漿抗壓、抗折、折壓比、干縮、開裂性能的改善效果，提出了利用聚丙烯纖維增強(qiáng)增韌機(jī)制砂水泥砂漿性能的關(guān)鍵技術(shù)與方法。 4)通過電鏡掃描分析機(jī)制砂水泥砂漿的SEM圖，進(jìn)行砂漿內(nèi)部的微觀結(jié)構(gòu)和作用機(jī)理的試驗(yàn)研究和理論分析。
[Abstract]:With the construction of large-scale infrastructure in China, the natural sand resources are becoming more and more tense, and the contradiction between supply and demand is becoming more and more acute. As the conventional raw materials of concrete and mortar, the utilization of mechanized sand has become the general trend. However, the current Code of Sand for Building (GB/T14684-2011) strictly limits the content of stone powder in the sand, which makes the sand produced by dust removal or washing method greatly reduce its own mobility because of its multi-edge angle, rough surface and poor rolling ability. It is easy to produce cement mortar with serious bleeding and poor cohesion. Therefore, it is necessary to study the reasonable increase of stone powder content in mechanized sand in order to improve the working performance of cement mortar. At the same time, there are still some problems in the cement mortar prepared by mechanical sand, such as early dry shrinkage, easy cracking and so on, so it is necessary to study and modify it with polypropylene fiber. At present, the research on using polypropylene fiber to improve the working performance of natural sand cement mortar is more profound and comprehensive, but the research on using polypropylene fiber to improve the working performance of machine-made sand cement mortar is relatively few. However, the research on the effect of mechanized sand and stone powder on the properties of cement mortar is mainly carried out under a single strength grade, and the influence of cement content on the content of stone powder is not taken into account, so the conclusions are different. In addition, the effect of stone powder content in mechanical sand on the water consumption of cement mortar is only described qualitatively, but there is a lack of quantitative analysis. Based on this, this paper mainly focuses on M5, M10, M15, M20 strength grade cement mortar to do the following aspects of work: 1) through trial mixing to find the change of water consumption of mechanism sand cement mortar with stone powder content, and put forward quantitative calculation method. 2) on the basis of ensuring the working performance of cement mortar, the variation of mass density, compression, bending resistance, dry shrinkage and crack resistance of cement mortar was studied when the content of stone powder in mechanism sand was 0, 7.9%, 10%, 15%, 20%, 25%, 30%. 3) on the basis of the optimum content of stone powder, the improvement effect of polypropylene fiber content and length on the compression, bending resistance, folding ratio, dry shrinkage and cracking properties of machined sand cement mortar was studied by adding polypropylene fiber with different length (6mm, 12mm, 18mm) and different content (0.6kgm3, 0.8kgm3, 1.0kgm3, 1.2kg 路m3), and the effect of the content and length of polypropylene fiber on the compression, bending resistance, folding ratio, dry shrinkage and cracking properties of mechanized sand cement mortar was studied by adding different lengths (6mm, 12mm, 18mm) and different content (0.6kg / m3, 1.0kg / m3, 1.2kg / m3). The key technology and method of using polypropylene fiber to strengthen and toughen the properties of sand cement mortar are put forward. 4) the experimental study and theoretical analysis of the microstructure and action mechanism of the mortar are carried out by scanning electron microscope (SEM) to analyze the SEM diagram of the sand cement mortar.
【學(xué)位授予單位】：華北水利水電大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU578.1

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