礦物摻合料對(duì)PHC管樁混凝土性能的影響
發(fā)布時(shí)間：2019-04-27 00:15
【摘要】：C80預(yù)應(yīng)力高強(qiáng)混凝土(Prestressed High-Strength Concrete,即PHC)管樁,廣泛應(yīng)用于各種樁基工程。石英粉、礦粉、粉煤灰是常用的三種礦物摻合料,鑒于目前有關(guān)這三種摻合料對(duì)壓蒸工藝制備PHC管樁混凝土性能的差異性影響研究報(bào)道較少,本文系統(tǒng)地研究了三種礦物摻合料對(duì)PHC管樁混凝土的力學(xué)性能、界面性能、抗氯離子滲透性能及抗硫酸鹽侵蝕性能的影響。論文的主要成果如下:(1)單、雙摻石英粉、礦粉、粉煤灰對(duì)PHC管樁混凝土立方體抗壓強(qiáng)度(fcu)、劈裂抗拉強(qiáng)度(fts)和軸心抗壓強(qiáng)度(fcp)影響的研究結(jié)果表明,與純水泥混凝土試件相比,摻量在10%-30%范圍內(nèi),單摻石英粉對(duì)提高fcu和fcp幅度效果最明顯,次之是單摻礦粉,在摻量不超過(guò)10%時(shí)單摻粉煤灰對(duì)fcu和fcp稍有提高,超過(guò)10%時(shí)則會(huì)降低fcu和fcp;石英粉和粉煤灰、礦粉和粉煤灰在滿(mǎn)足fcu和fcp要求的前提下,石英粉和粉煤灰、礦粉和粉煤灰兩兩雙摻有利于提高fts。(2)與純水泥混凝土試件相比,無(wú)論單摻或兩兩復(fù)摻礦物摻合料石英粉、礦粉、粉煤灰,均可提高PHC管樁混凝土的韌性,而摻入粉煤灰的效果最為明顯。SEM分析表明,摻入粉煤灰的壓蒸凈漿試件中水化產(chǎn)物大孔少,形成了較為明顯的空間網(wǎng)架結(jié)構(gòu),有利于提高管樁混凝土的韌性。(3)礦物摻合料對(duì)PHC管樁混凝土的應(yīng)力-應(yīng)變關(guān)系的影響研究表明,不同摻合料對(duì)PHC管樁混凝土的峰值應(yīng)力和峰值應(yīng)變的影響規(guī)律與其對(duì)立方體抗壓強(qiáng)度的類(lèi)似,均呈單調(diào)線性增加趨勢(shì)。三種摻合料制備的PHC管樁高強(qiáng)混凝土的應(yīng)力-應(yīng)變曲線上升段相近,應(yīng)力達(dá)到峰值的范圍均在峰值應(yīng)力的80%~90%,當(dāng)應(yīng)力達(dá)峰值前曲線的上升段基本變成了直線,臨界裂縫應(yīng)力點(diǎn)和峰值應(yīng)力接近;但是下降段區(qū)別較大,摻入粉煤灰或礦粉時(shí),下降段較為平緩,摻入石英粉時(shí)下降段斜率較大,呈直線。在試驗(yàn)的基礎(chǔ)上,構(gòu)建了摻礦物摻合料PHC管樁混凝土的應(yīng)力-應(yīng)變本構(gòu)模型。(4)礦物摻合料對(duì)PHC管樁混凝土水泥石和骨料界面性質(zhì)的影響研究表明,壓蒸工藝制備的管樁混凝土的水泥石和骨料的界面仍存在明顯的界面過(guò)渡區(qū),與純水泥混凝土試件相比,摻入石英粉、礦粉、粉煤灰界面過(guò)渡區(qū)的CH厚度均有所減小,摻合料對(duì)顯微硬度的影響規(guī)律與對(duì)立方體抗壓強(qiáng)度的影響規(guī)律相似。(5)礦物摻合料對(duì)PHC管樁混凝土的抗氯離子滲透性和抗硫酸鹽腐蝕性的影響研究表明,與純水泥混凝土試件相比,摻入摻合料的混凝土抗氯離子滲透性均有所提高,雙摻摻合料的效果優(yōu)于單摻的;單摻石英粉會(huì)降低PHC管樁混凝土的抗硫酸鹽侵蝕性,單摻礦粉、粉煤灰或三種礦物摻合料兩兩雙摻均有利于提高PHC管樁混凝土的抗硫酸侵蝕性。壓汞試驗(yàn)表明摻入礦物摻合料均能有效改善管樁混凝土的孔結(jié)構(gòu),但是單摻石英粉會(huì)增加有害孔含量,這是單摻石英粉降低管樁混凝土抗硫酸鹽侵蝕性的主要原因。
[Abstract]:C80 prestressed high strength concrete (Prestressed High-Strength Concrete,) pipe pile is widely used in various pile foundation projects. Quartz powder, mineral powder and fly ash are three kinds of mineral admixtures in common use. In view of the influence of these three admixtures on the performance difference of PHC pipe pile prepared by autoclave process, there are few reports reported at present. In this paper, the effects of three mineral admixtures on the mechanical properties, interface properties, chloride penetration resistance and sulfate corrosion resistance of PHC pipe pile concrete are systematically studied. The main achievements of this paper are as follows: (1) the effects of single, double-mixed quartz powder, mineral powder and fly ash on the cube compressive strength of PHC tubular pile concrete (fcu), splitting tensile strength (fts) and axial compressive strength (fcp) are studied. Compared with the pure cement concrete specimen, the addition of quartz powder has the most obvious effect on increasing the amplitude of fcu and fcp in the range of 10% and 30%, followed by the single mineral powder. When the content of fly ash is less than 10%, the fcu and fcp can be increased slightly. Lower fcu and fcp; when more than 10% Quartz powder and fly ash, mineral powder and fly ash meet the requirements of fcu and fcp, both of quartz powder and fly ash, mineral powder and fly ash can improve fts. (2) compared with pure cement concrete. The toughness of concrete with PHC pipe pile can be improved by adding quartz powder, mineral powder and fly ash with single or dual admixture of mineral, and the effect of admixture with fly ash is the most obvious. SEM analysis shows that the toughness of concrete can be improved by adding fly ash. There are few hydration products in the autoclaved paste specimen mixed with fly ash, and the space structure is formed. (3) the effect of mineral admixture on the stress-strain relationship of PHC pipe pile concrete is studied. The influence of different admixtures on the peak stress and strain of PHC tubular pile concrete is similar to that of the cubic compressive strength. The stress-strain curve of high-strength concrete of PHC pipe pile prepared by three kinds of admixtures is similar, and the range of stress reaching peak value is 80% ~ 90% of peak stress. When the stress reaches peak value, the rising section of curve becomes straight line basically. The stress point and peak stress of critical crack are close to each other; When the fly ash or ore powder is added, the descending section is relatively smooth, and the slope of the descending section is larger when the quartz powder is added, showing a straight line. On the basis of experiment, the stress-strain constitutive model of PHC pipe pile concrete with mineral admixture is constructed. (4) the effect of mineral admixture on the interface properties of cement paste and aggregate of PHC pipe pile concrete is studied. The interface between cement stone and aggregate of pipe pile concrete prepared by autoclave still has obvious interface transition zone. Compared with pure cement concrete specimen, the CH thickness of interface transition zone of concrete mixed with quartz powder, mineral powder and fly ash decreases to a certain extent. The influence of mineral admixture on microhardness is similar to that of opposite square compressive strength. (5) the influence of mineral admixture on chloride ion permeability and sulfate corrosion resistance of PHC pipe pile concrete shows that the effect of mineral admixture on chloride ion permeability and sulfate corrosion resistance of concrete is similar to that of opposite square. Compared with the pure cement concrete specimen, the chloride ion permeability of the concrete mixed with the admixture is improved, and the effect of the double admixture is better than that of the single admixture. The anti-sulfate corrosion resistance of PHC pipe pile concrete can be reduced by adding single quartz powder, single admixture of mineral powder, fly ash or three kinds of mineral admixture can improve the resistance of PHC pipe pile concrete to sulfuric acid erosion. Mercury pressure test shows that adding mineral admixture can effectively improve the pore structure of pipe pile concrete, but only adding quartz powder will increase harmful pore content, which is the main reason for reducing sulfate corrosion resistance of concrete pipe pile concrete with single addition of quartz powder.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TU528
本文編號(hào)：2466518
[Abstract]:C80 prestressed high strength concrete (Prestressed High-Strength Concrete,) pipe pile is widely used in various pile foundation projects. Quartz powder, mineral powder and fly ash are three kinds of mineral admixtures in common use. In view of the influence of these three admixtures on the performance difference of PHC pipe pile prepared by autoclave process, there are few reports reported at present. In this paper, the effects of three mineral admixtures on the mechanical properties, interface properties, chloride penetration resistance and sulfate corrosion resistance of PHC pipe pile concrete are systematically studied. The main achievements of this paper are as follows: (1) the effects of single, double-mixed quartz powder, mineral powder and fly ash on the cube compressive strength of PHC tubular pile concrete (fcu), splitting tensile strength (fts) and axial compressive strength (fcp) are studied. Compared with the pure cement concrete specimen, the addition of quartz powder has the most obvious effect on increasing the amplitude of fcu and fcp in the range of 10% and 30%, followed by the single mineral powder. When the content of fly ash is less than 10%, the fcu and fcp can be increased slightly. Lower fcu and fcp; when more than 10% Quartz powder and fly ash, mineral powder and fly ash meet the requirements of fcu and fcp, both of quartz powder and fly ash, mineral powder and fly ash can improve fts. (2) compared with pure cement concrete. The toughness of concrete with PHC pipe pile can be improved by adding quartz powder, mineral powder and fly ash with single or dual admixture of mineral, and the effect of admixture with fly ash is the most obvious. SEM analysis shows that the toughness of concrete can be improved by adding fly ash. There are few hydration products in the autoclaved paste specimen mixed with fly ash, and the space structure is formed. (3) the effect of mineral admixture on the stress-strain relationship of PHC pipe pile concrete is studied. The influence of different admixtures on the peak stress and strain of PHC tubular pile concrete is similar to that of the cubic compressive strength. The stress-strain curve of high-strength concrete of PHC pipe pile prepared by three kinds of admixtures is similar, and the range of stress reaching peak value is 80% ~ 90% of peak stress. When the stress reaches peak value, the rising section of curve becomes straight line basically. The stress point and peak stress of critical crack are close to each other; When the fly ash or ore powder is added, the descending section is relatively smooth, and the slope of the descending section is larger when the quartz powder is added, showing a straight line. On the basis of experiment, the stress-strain constitutive model of PHC pipe pile concrete with mineral admixture is constructed. (4) the effect of mineral admixture on the interface properties of cement paste and aggregate of PHC pipe pile concrete is studied. The interface between cement stone and aggregate of pipe pile concrete prepared by autoclave still has obvious interface transition zone. Compared with pure cement concrete specimen, the CH thickness of interface transition zone of concrete mixed with quartz powder, mineral powder and fly ash decreases to a certain extent. The influence of mineral admixture on microhardness is similar to that of opposite square compressive strength. (5) the influence of mineral admixture on chloride ion permeability and sulfate corrosion resistance of PHC pipe pile concrete shows that the effect of mineral admixture on chloride ion permeability and sulfate corrosion resistance of concrete is similar to that of opposite square. Compared with the pure cement concrete specimen, the chloride ion permeability of the concrete mixed with the admixture is improved, and the effect of the double admixture is better than that of the single admixture. The anti-sulfate corrosion resistance of PHC pipe pile concrete can be reduced by adding single quartz powder, single admixture of mineral powder, fly ash or three kinds of mineral admixture can improve the resistance of PHC pipe pile concrete to sulfuric acid erosion. Mercury pressure test shows that adding mineral admixture can effectively improve the pore structure of pipe pile concrete, but only adding quartz powder will increase harmful pore content, which is the main reason for reducing sulfate corrosion resistance of concrete pipe pile concrete with single addition of quartz powder.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TU528
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 劉數(shù)華,方坤河,曾力;降低高強(qiáng)混凝土脆性的試驗(yàn)研究[J];建筑材料學(xué)報(bào);2005年02期
相關(guān)博士學(xué)位論文 前1條
1 楊婷婷;基于集料功能設(shè)計(jì)的水泥石界面性能研究[D];武漢理工大學(xué);2010年
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