本文選題：煤矸石混凝土　切入點：力學性能　出處：《沈陽建筑大學》2015年碩士論文　論文類型：學位論文

【摘要】：煤矸石是煤炭工業(yè)產(chǎn)生的廢物之一,每年都在產(chǎn)生大量的煤矸石、對環(huán)境有嚴重的污染。對煤矸石不進行合理的利用,將產(chǎn)生巨大的社會、經(jīng)濟和環(huán)境的損失。利用煤矸石生產(chǎn)集料來拌制水泥混凝土,可以大量減少土木工程中對天然集料的使用量,具有較好的經(jīng)濟效益和社會效益。本課題通過煤矸石作為粗集料取代碎石制備混凝土,采用單因素和優(yōu)化設計試驗方案,以混凝土抗壓強度、抗?jié)B性和抗凍性為考核指標,確定煤矸石取代碎石的合理摻量范圍,研究了煤矸石的摻量、水膠比的大小、粉煤灰的摻量、外加劑的種類和摻量對混凝土抗?jié)B性、抗凍性的影響規(guī)律,并于普通混凝土做出對比。研究結果表明:(1)通過煤矸石和普通碎石的基本物理性能的對比可知,煤矸石孔隙率較大,含水率較高,吸水性較強,含泥量較大;壓碎指標較大;以煤矸石混凝土拌合物的工作性和力學性能為考核指標,確定煤矸石取代碎石的合理摻量范圍在60%以內(nèi)。(2)在基準配合比條件下,隨著煤矸石取代碎石的量從0%增加到60%,混凝土的抗壓強度、抗?jié)B性、抗凍性有不同程度的降低,抗壓28天強度從55.7MPa下降到40.8MPa,抗?jié)B壓力從1.3MPa下降到0.9MPa,凍融次數(shù)從300次以上下降到150次以下,煤矸石的最佳取代量在40%左右;水膠比從0.35增大到0.45,抗?jié)B壓力從1.3MPa下降到0.7MPa,凍融次數(shù)從300次下降到100次左右,確定滿足C40混凝土的水膠比不大于0.4;粉煤灰作為礦物摻合料,當摻量在10%左右抗凍抗?jié)B效果最好,抗?jié)B壓力可達1.2MPa,凍融循環(huán)可達300次,超過20%時,混凝土抗?jié)B性、抗凍性有明顯的下降趨勢;選用聚羧酸減水劑和引氣劑可以顯著提高混凝土抗?jié)B、抗凍性,聚羧酸減水劑和引氣劑的摻量分別占膠凝材料約0.5%和0.02%時,抗?jié)B和抗凍能力最強,均可達到1.1MPa和300次凍融循環(huán);兩種外加劑復合使用時,比單摻一種外加劑效果更好,抗?jié)B和抗凍分別可達到1.3MPa和350次凍融循環(huán)。(3)摻入礦物摻合料和外加劑可以改善混凝土的孔結構,經(jīng)凍融循環(huán)后,最可幾孔徑和總孔體積減小,孔結構劣化的速率明顯減慢。300次凍融前后比較,摻入粉煤灰可使混凝土的總孔體積增大的百分比從12.6%下降到9.2%,其最佳摻量在膠凝材料的10%;復合使用聚羧酸減水劑和引氣劑可使混凝土總孔體積增大的百分比從12.8%下降到5.7%,減水劑和引氣劑的摻量分別為0.4%和0.02%時達到最佳。
[Abstract]:Coal gangue is one of the wastes produced by the coal industry. It produces a large amount of coal gangue every year, which causes serious pollution to the environment. If the coal gangue is not used reasonably, it will produce a huge society. Economic and environmental losses. The use of coal gangue to produce aggregate to mix cement concrete can greatly reduce the amount of natural aggregate used in civil engineering. In this paper, coal gangue is used as coarse aggregate instead of crushed stone to prepare concrete. Single factor and optimum design test scheme are adopted. The compressive strength, impermeability and frost resistance of concrete are taken as the assessment index. The reasonable dosage range of coal gangue instead of crushed stone is determined. The influence of coal gangue content, water / binder ratio, fly ash content, type and amount of admixture on the impermeability and frost resistance of concrete is studied. The research results show that the coal gangue has higher porosity, higher moisture content, stronger water absorption, larger mud content, larger crushing index, higher porosity, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water content, higher water. Taking the workability and mechanical properties of coal gangue concrete mixture as evaluation indexes, it is determined that the reasonable dosage range of coal gangue replacing crushed stone is less than 60% under the condition of standard mix ratio. As the amount of coal gangue replacing crushed stone increased from 0% to 60, the compressive strength, impermeability, and frost resistance of concrete decreased to varying degrees. The compressive strength decreased from 55.7 MPA to 40.8 MPA, the impermeability pressure decreased from 1.3 MPA to 0.9 MPA, the freeze-thaw times decreased from more than 300 times to less than 150 times, and the optimum substitution of coal gangue was about 40%. The water-binder ratio increased from 0.35 to 0.45, the impermeability pressure decreased from 1.3 MPA to 0.7 MPa, and the freeze-thaw times decreased from 300 times to about 100 times. The impervious pressure can reach 1.2 MPA, the freeze-thaw cycle can reach 300 times, when the concrete is more than 20, the impermeability and the frost resistance of the concrete have an obvious downward trend, and the use of polycarboxylic acid water reducer and air entraining agent can significantly improve the impermeability and frost resistance of concrete. When the content of polycarboxylic acid water reducer and air entraining agent is about 0.5% and 0.02, respectively, the impermeability and freezing resistance are the strongest, which can reach 1.1MPa and 300th freeze-thaw cycle respectively. When the two admixtures are combined, the effect is better than that of single admixture. The pore structure of concrete can be improved by adding mineral admixture and admixture, which can reach 1.3MPa and 350 freeze-thaw cycles, respectively. After freeze-thaw cycle, the pore size and total pore volume of concrete can be reduced. The rate of deterioration of pore structure was significantly decreased. 300 times before and after freezing and thawing, The percentage of the total pore volume of concrete decreased from 12.6% to 9.2 by adding fly ash, and the optimum content was 10% of the cementing material, and the percentage of the total pore volume of concrete increased from 12.8% to 12.8% by using polycarboxylic acid water reducer and air entraining agent. When the ratio of water reducer and air entraining agent is 0.4% and 0.02, respectively, the best results are obtained.
【學位授予單位】：沈陽建筑大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU528

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相關期刊論文 前2條

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本文編號：1595551