發(fā)布時間：2018-04-13 13:08

  本文選題：石粉 + 機制砂��； 參考：《重慶交通大學(xué)》2014年碩士論文

【摘要】：機制砂代替天然砂是混凝土行業(yè)可持續(xù)發(fā)展的趨勢，不僅支持我國基礎(chǔ)建設(shè)的持續(xù)發(fā)展，解決部分地區(qū)天然砂砂源緊缺的問題，而且對保護生態(tài)環(huán)境、降低工程成本均有重大的實際價值。 首先，本文對機制砂自身特性進行研究，從宏觀與微觀兩方面入手:采用對比相同級配下天然砂與機制砂砂漿性能，研究發(fā)現(xiàn)機制砂對強度具有增強效應(yīng)，但對工作性有負面效應(yīng)；運用SEM與XRD對石粉進行形貌與成份分析，發(fā)現(xiàn)石粉是一種非玻璃體，且破碎卵石與石灰?guī)r的石粉主要成份分別為SiO2和CaCO3；通過內(nèi)摻與外摻不同石粉含量的水泥凈漿流動度試驗，結(jié)果表明石粉對減水劑有吸附作用，并對水泥水化有加速效應(yīng)；運用均勻設(shè)計研究了機制砂1.18mm以下顆粒含量對機制砂性能及砂漿性能的影響，提出機制砂顆粒級配的關(guān)鍵篩孔為0.6mm。 其次，本文以C55機制砂混凝土的配制和性能測試為基礎(chǔ)，通過正交設(shè)計優(yōu)選了C55機制砂混凝土配合比的配制參數(shù)，并在相同條件下改變混凝土中的細集料，與水洗機制砂、原狀機制砂和不同巖性的砂進行對比研究。研究了機制砂對混凝土工作性、力學(xué)性能、耐久性及體積變形性的影響，并探討了機制砂生產(chǎn)不水洗的可行性。試驗結(jié)果表明:采用水洗機制砂配制的C55高性能混凝土的總開裂面積為320mm2/m2 ，早期抗裂性為IV級，滲等級為P17，56天電通量為461C；原狀機制砂石粉含量為6.3%，亞甲藍為1.0g/kg，其混凝土抗?jié)B性、抗裂性及體積變形性能比水洗機制砂混凝土優(yōu)，當(dāng)機制砂石粉的亞甲藍值為1.0g/kg時，對高強高性能混凝土可適當(dāng)放寬石粉含量界限到6%；機制砂混凝土的力學(xué)性能、抗裂性能及體積變形性能在相同條件下均優(yōu)于天然砂混凝土，但其抗?jié)B性能不及天然砂混凝土；機制砂僅巖性的改變，對混凝土性能無顯著影響，當(dāng)石粉含量在6%內(nèi)對機制砂混凝土長期性能無明顯影響。 最后，通過SEM電鏡掃描和顯微硬度測試技術(shù)，研究發(fā)現(xiàn)細集料巖性的改變不會影響混凝土水化產(chǎn)物形貌；石粉具有填充效應(yīng)和晶核效應(yīng)；適量的石粉能改善混凝土內(nèi)部骨料界面過渡區(qū)的不均勻性。 通過研究，，采用機制砂可配制橋梁主梁用C55高性能混凝土。
[Abstract]:It is the trend of sustainable development of concrete industry to replace natural sand with machine-made sand. It not only supports the sustainable development of infrastructure in China, but also solves the problem of shortage of natural sand source in some areas, and it also protects the ecological environment.It is of great practical value to reduce the project cost.First of all, this paper studies the characteristics of machined sand, starting from macro and micro aspects: by comparing the properties of natural sand and machined mortar with the same gradation, it is found that the mechanical sand has an enhanced effect on strength.SEM and XRD were used to analyze the morphology and composition of stone powder, and it was found that stone powder is a kind of non-vitreous body.The main components of crushed pebble and limestone are SiO2 and CaCO3 respectively. Through the flow test of cement paste with and without different content of stone powder, the results show that the stone powder can adsorb water reducer and accelerate the hydration of cement.The effect of particle content below 1.18mm on the properties of machined sand and mortar was studied by uniform design. The key sieve hole of grain gradation of machined sand was 0.6mm.Secondly, on the basis of the compounding and performance testing of C55 mechanism sand concrete, the compounding parameters of C55 mechanism sand concrete are selected by orthogonal design, and the fine aggregate in concrete is changed under the same conditions, and the washing mechanism sand is changed under the same conditions.A comparative study was carried out between the undisturbed sand and the sand of different lithology.The effects of machine-made sand on workability, mechanical properties, durability and volume deformation of concrete were studied, and the feasibility of unwashed production of machine-made sand was discussed.The test results show that the total cracking area of C55 high performance concrete prepared by washing mechanism sand is 320mm2/m2.The early crack resistance is grade IV, the permeation grade is P1756-day electric flux is 461C, the content of raw mechanism sand and stone powder is 6.3, methylene blue is 1.0 g / kg, the impermeability, crack resistance and volume deformation of concrete are better than that of water-washed sand concrete.When the methylene blue value of machined sand powder is 1.0g/kg, the limit of stone powder content can be relaxed to 6 for high strength and high performance concrete, and the mechanical properties, crack resistance and volume deformation properties of machined sand concrete are better than that of natural sand concrete under the same conditions.However, its impermeability is not as good as that of natural sand concrete, but only the change of lithology of machined sand has no significant effect on the concrete performance, and when the content of stone powder is within 6%, it has no obvious effect on the long-term performance of machined sand concrete.Finally, by means of SEM scanning electron microscope and microhardness test, it is found that the change of lithology of fine aggregate will not affect the morphology of hydration products of concrete, and the stone powder has filling effect and nucleation effect.Proper amount of stone powder can improve the heterogeneity of the interfacial transition zone of concrete aggregate.Through the research, the C 55 high performance concrete for bridge main girder can be made by using machined sand.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U444

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本文編號：1744628