本文關(guān)鍵詞： 機(jī)制砂 低強(qiáng)度 高性能混凝土 和易性 配合比設(shè)計　出處：《西南交通大學(xué)》2013年碩士論文　論文類型：學(xué)位論文

【摘要】：機(jī)制砂是經(jīng)過機(jī)械破碎、篩分而制成的,粒徑小于4.75mm的巖石顆粒。與河砂不同,由于機(jī)制砂有顆粒較粗糙、棱角多、級配較差的特點,應(yīng)用在中低強(qiáng)度等級混凝土中時,用水量相對較多,混凝土拌合物工作性差,容易泌水離析。機(jī)制砂各項技術(shù)指標(biāo)由于生產(chǎn)技術(shù)不同而各異,因此要得到性能良好便于施工的的混凝土,就對配合比提出了更高的要求。因此探索機(jī)制砂的哪些特性對混凝土的和易性影響較大,以及對于不同特性的機(jī)制砂如何調(diào)整混凝土的配合比使得其和易性優(yōu)良,這對工程應(yīng)用有很大實際意義。本文主要目標(biāo)是研究怎樣配制出具有良好和易性的低強(qiáng)度高性能機(jī)制砂混凝土。主要研究內(nèi)容有： (1)低強(qiáng)度機(jī)制砂混凝土和易性影響因素分析 結(jié)合低強(qiáng)度機(jī)制砂混凝土和易性要求,初步分析出混凝土和易性影響因素,為之后的配合比設(shè)計和實驗分析提供理論依據(jù)。 (2)低強(qiáng)度高性能機(jī)制砂混凝土配合比的設(shè)計與優(yōu)化 根據(jù)機(jī)制砂混凝土的和易性、力學(xué)性能與耐久性能特點,結(jié)合對低強(qiáng)度高性能機(jī)制砂混凝土和易性能的認(rèn)識,在參考大量文獻(xiàn)的基礎(chǔ)上,總結(jié)現(xiàn)有高性能混凝土配合比設(shè)計方法,對低強(qiáng)度高性能機(jī)制砂混凝土配合比進(jìn)行設(shè)計與優(yōu)化。 在《普通混凝土配合比設(shè)計規(guī)程》(JGJ55-2011)和高性能混凝土全計算法配合比設(shè)計的基礎(chǔ)上,李固華教授提出了一種新的配合比設(shè)計方法——粉體當(dāng)量體積法。這種方法是通過確定各種粉體單位體積用水量,與水泥單位體積用水量之比,來確定粉體的當(dāng)量系數(shù),在計算粉體當(dāng)量總體積過程中,粉體體積要乘以當(dāng)量系數(shù)。 在上述配合比方法設(shè)計的基礎(chǔ)上,實驗并分析了水膠比、粉體當(dāng)量總體積、用水量、砂率等不同因素,對低強(qiáng)度高性能機(jī)制砂混凝土和易性的影響,并確定了水膠比為0.6時,用水量為170L,粉體當(dāng)量總體積為170L,砂率為45%時,混凝土拌合物的和易性最佳。 (3)礦物摻合料和外加劑對低強(qiáng)度機(jī)制砂混凝土和易性的影響 在以上配合比方法的基礎(chǔ)上,在混凝土中添加了礦粉、羥丙基甲基纖維素醚、膨潤土、聚丙烯纖維、偏高嶺土等,并對混凝土拌合物和易性、成型試塊的抗壓強(qiáng)度進(jìn)行測試,對以上配合比方法基礎(chǔ)上的結(jié)論進(jìn)行實驗驗證和理論分析。并在保證混凝土和易性良好、抗壓強(qiáng)度滿足的條件下,確定外加劑的最佳摻量。
[Abstract]:The machine-made sand is made by mechanical crushing and sieving, and its diameter is less than 4.75mm. Different from the river sand, the machine-made sand has the characteristics of coarse grain, many angles and poor gradation. When used in medium and low strength grade concrete, the water consumption is relatively high, the mixing property of concrete is poor, and it is easy to bleed and separate. The technical indexes of machine-made sand are different from each other because of different production technology. Therefore, in order to obtain the concrete with good performance and easy construction, it puts forward higher requirements on the mix ratio. Therefore, exploring which characteristics of the machine-made sand has a great influence on the concrete and its easiness. And how to adjust the mix ratio of concrete for different characteristics of the machine-made sand makes it easy to use. This is of great practical significance to engineering application. The main purpose of this paper is to study how to prepare low strength and high performance machined sand concrete with good and easiness. The main contents of this paper are as follows: Analysis of influencing factors of low strength machined Sand concrete and its ease Combined with the requirements of low strength machine-made sand concrete and its easiness, the influence factors of concrete and easiness are preliminarily analyzed, which provides the theoretical basis for the later mix ratio design and experimental analysis. Design and Optimization of mix ratio of low strength and High performance Sand concrete According to the characteristics of mechanical properties, mechanical properties and durability of machine-made sand concrete, combined with the understanding of low-strength and high-performance machine-made sand concrete and easy performance, based on a large number of references. This paper summarizes the existing design methods of high performance concrete mix ratio, and designs and optimizes the mix ratio of low strength and high performance mechanism sand concrete. On the basis of JGJ55-2011) and the design of mix ratio of high performance concrete. Professor Li Guhua has put forward a new mix ratio design method-powder equivalent volume method. This method is based on determining the ratio of water consumption per unit volume of various powders to the water consumption per unit volume of cement. In the process of calculating the total equivalent volume of powder, the volume of powder should be multiplied by the equivalent coefficient. On the basis of the design of the above mix ratio, the effects of different factors, such as water-binder ratio, total equivalent volume of powder, water consumption and sand ratio, on the low strength and high performance machine-made sand concrete and its easiness were tested and analyzed. When the water / binder ratio is 0.6, the water consumption is 170 L, the equivalent volume of powder is 170 L, and the sand ratio is 45%, the mixing property of concrete is the best. Effect of mineral admixture and admixture on low strength machined sand concrete and its easyness On the basis of the above mixing method, mineral powder, hydroxypropyl methyl cellulose ether, bentonite, polypropylene fiber, metakaolin were added to the concrete, and the concrete was mixed and easy. The compressive strength of the molding test block is tested, and the conclusion based on the above mix ratio method is verified and analyzed theoretically, and under the condition that the concrete is easy to work and the compressive strength is satisfied. Determine the optimum amount of admixture.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU528

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