本文選題：早齡期混凝土 + 力學(xué)性能��； 參考：《北京交通大學(xué)》2016年博士論文

【摘要】：混凝土早齡期性能指標(biāo)是推定混凝土質(zhì)量優(yōu)劣的重要依據(jù)之一。早齡期混凝土力學(xué)性能不僅是影響施工期結(jié)構(gòu)安全的關(guān)鍵因素和工程進度的制約因素,而且直接影響混凝土服役期性能及其耐久性。目前早齡期鋼筋混凝土領(lǐng)域的研究多限于材料領(lǐng)域的研究,對于早齡期混凝土構(gòu)件尚未形成系統(tǒng)研究分析。因此,研究早齡期混凝土材料與構(gòu)件的力學(xué)性能及變化規(guī)律有重要的理論意義與應(yīng)用價值。本文完成的主要研究工作及創(chuàng)新成果如下:(1)完成了齡期為0.5天、1天、3天、7天、14天、28天和90天的混凝土試塊立方體抗壓強度、軸心抗壓強度、劈裂強度、靜力彈性模量、單軸受壓全曲線和粘結(jié)滑移試驗研究,對試驗結(jié)果進行分析,得出混凝土"三強度一模量"隨齡期的增長規(guī)律及計算方法,在試驗基礎(chǔ)上建立了早齡期混凝土單軸本構(gòu)關(guān)系和粘結(jié)滑移本構(gòu)關(guān)系曲線。(2)完成了 1天、3天、7天、28天早齡期C40鋼筋混凝土梁試驗,對不同齡期試件在分級荷載作用下的典型破壞形態(tài)進行深入分析,研究了荷載、齡期等因素對構(gòu)件承載能力、變形性能及前期受荷對后期承載力的影響,提出了早齡期鋼筋混凝土梁正截面抗彎承載力、極限承載力計算公式。利用ABAQUS軟件模擬了齡期為3天、7天、28天鋼筋和混凝土的應(yīng)力、變形圖,并結(jié)合配筋率、剪跨比進行了有限元擴展分析。(3)完成了1天、3天、7天、28天齡期C40鋼筋混凝土柱偏心加載試驗,測量了試驗構(gòu)件的撓度、軸向變形、轉(zhuǎn)動變形及截面應(yīng)變,并繪制了在單調(diào)荷載作用下柱的裂縫分布圖,全面分析了荷載-應(yīng)變曲線及其特征,提出了早齡期鋼筋混凝土偏心受壓柱的正截面開裂荷載計算公式,并依據(jù)修正平截面假定法,提出一種早齡期偏心受壓承載力的實用計算方法,其計算值與試驗數(shù)據(jù)吻合良好。在試驗基礎(chǔ)上,運用有限元軟件ABAQUS模擬得到的3天、7天、28天的極限荷載與試驗荷載較為吻合,并結(jié)合配筋率、偏心距進行了有限元擴展分析。(4)根據(jù)C40混凝土早齡期性能試驗,研究了原材料、混凝土配合比等對混凝土的密實度和抗裂性的影響,并通過混凝土早齡期碳化深度、自由收縮、限制膨脹率、平板約束等試驗,分析和驗證了所選原材料、配合比對混凝土耐久性的影響,建立了早齡期混凝土高耐久性的技術(shù)控制指標(biāo)。本文通過系統(tǒng)的試驗研究,提出了 C40早齡期混凝土的抗壓強度、劈拉強度、彈性模量和單軸受壓全曲線隨齡期的發(fā)展規(guī)律,推導(dǎo)出合理的受壓本構(gòu)關(guān)系模型;對早齡期鋼筋混凝土受彎、受壓構(gòu)件的受荷特性和破壞機理進行研究分析,提出了早齡期鋼筋混凝土構(gòu)件極限承載力計算公式;結(jié)合早齡期性能特點,研究原材料選擇、混凝土配合比對混凝土高耐久性的影響,提出了控制混凝土密實度、抗裂性的技術(shù)指標(biāo)。
[Abstract]:The early age performance index of concrete is one of the important bases to estimate the quality of concrete. The mechanical properties of early age concrete are not only the key factors of structural safety during construction period and the restriction factor of project progress, but also directly affect the performance and durability of concrete service life. At present, most of the researches in the field of early age reinforced concrete are limited to those in the field of materials, but there is no systematic research and analysis on early age concrete members. Therefore, it is of great theoretical significance and practical value to study the mechanical properties and variation law of early age concrete materials and members. The main research work and innovative results of this paper are as follows: (1) the cube compressive strength, axial compressive strength, splitting strength, static elastic modulus of concrete test blocks with the age of 0.5 days / 1 day / 3 days / 7 days / 14 days / 28 days and 90 days are completed. The experimental study of uniaxial compression curve and bond-slip test is carried out. The experimental results are analyzed, and the increasing law and calculation method of concrete "three strength and one modulus" with age are obtained. The uniaxial constitutive relation and bond-slip constitutive relation curve of early age concrete were established on the basis of the test. In this paper, the typical failure patterns of specimens of different ages under graded loads are analyzed in depth. The effects of load, age and other factors on the bearing capacity, deformation performance and early loading on the later bearing capacity of the members are studied. The formulas of flexural bearing capacity and ultimate bearing capacity of early age reinforced concrete beams are presented. By using Abaqus software, the stress and deformation diagram of steel bar and concrete with the age of 3 days, 7 days and 28 days were simulated, and the reinforcement ratio was combined. The shear span ratio was analyzed by finite element method. (3) the eccentric loading test of C40 reinforced concrete column at 28 days of age was completed in 1 day, 3 days, 7 days and 28 days. The deflection, axial deformation, rotational deformation and cross section strain of the test members were measured. The crack distribution diagram of columns under monotonic load is drawn, the load-strain curve and its characteristics are analyzed comprehensively, and the formula for calculating the normal section cracking load of eccentric compression columns of early age reinforced concrete is put forward. On the basis of the modified plane section assumption method, a practical method for calculating the eccentricity compressive capacity of early age is proposed. The calculated values are in good agreement with the experimental data. On the basis of the test, the limit load of 3 days and 7 days and 28 days obtained by using the finite element software Abaqus is in good agreement with the test load. Combining with the reinforcement ratio and eccentricity, the finite element expansion analysis is carried out. (4) according to the early age performance test of C40 concrete, the finite element expansion analysis is carried out on the basis of the reinforcement ratio and eccentricity. The effects of raw materials and concrete mix ratio on the compactness and crack resistance of concrete are studied. The selected raw materials are analyzed and verified through the tests of early age carbonation depth, free shrinkage, limited expansion rate, plate restraint, etc. The technical control index of high durability of early age concrete is established based on the effect of mix ratio on durability of concrete. In this paper, through systematic test and study, the compressive strength, splitting tensile strength, elastic modulus and uniaxial compressive full curve of C40 early age concrete are put forward, and the reasonable constitutive relation model of compression is deduced. In this paper, the loading characteristics and failure mechanism of early age reinforced concrete members under bending and compression are studied and analyzed, and the formula for calculating ultimate bearing capacity of early age reinforced concrete members is put forward, and the selection of raw materials is studied according to the characteristics of early age behavior. The influence of concrete mix ratio on the high durability of concrete is discussed, and the technical index of controlling the compactness and crack resistance of concrete is put forward.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TU528

【參考文獻】

相關(guān)期刊論文 前10條

1 李夕兵;王世鳴;周韜;黃麟淇;周健;;不同沖擊條件下早齡期混凝土的力學(xué)特性[J];中國有色金屬學(xué)報;2015年06期

2 陳超;宋曉濱;;早齡期混凝土與鋼筋粘結(jié)時變性能試驗研究[J];結(jié)構(gòu)工程師;2014年03期

3 權(quán)磊;田波;馮德成;李新凱;;基于成熟度理論的水泥混凝土早期強度預(yù)測模型研究[J];公路交通科技(應(yīng)用技術(shù)版);2012年02期

4 謝軍;;早齡期混凝土強度和變形特性的試驗分析[J];低溫建筑技術(shù);2011年06期

5 侯東偉;張君;;早齡期混凝土全變形曲線的試驗測量與分析[J];建筑材料學(xué)報;2010年05期

6 盧姍姍;鄭文忠;;GFRP筋活性粉末混凝土梁正截面抗裂度計算方法[J];哈爾濱工業(yè)大學(xué)學(xué)報;2010年04期

7 朱伯芳;楊萍;;混凝土的半熟齡期——改善混凝土抗裂能力的新途徑[J];水利水電技術(shù);2008年05期

8 萬見明;高日;;活性粉末混凝土梁正截面抗裂計算方法[J];建筑結(jié)構(gòu);2007年12期

9 劉宏偉;吳勝興;;無損檢測方法推定混凝土早齡期靜彈性模量試驗研究[J];混凝土;2007年09期

10 李杰;任曉丹;楊衛(wèi)忠;;混凝土二維本構(gòu)關(guān)系試驗研究[J];土木工程學(xué)報;2007年04期

相關(guān)博士學(xué)位論文 前2條

1 胡曉鵬;早齡期混凝土結(jié)構(gòu)性能時變規(guī)律研究[D];西安建筑科技大學(xué);2011年

2 楊勇;型鋼混凝土粘結(jié)滑移基本理論及應(yīng)用研究[D];西安建筑科技大學(xué);2003年

相關(guān)碩士學(xué)位論文 前8條

1 楊振坤;C40早齡期混凝土柱承載性能試驗研究[D];北京交通大學(xué);2014年

2 王夢夢;C40早齡期混凝土力學(xué)性能試驗研究[D];北京交通大學(xué);2014年

3 顧文發(fā);C40商品混凝土早齡期力學(xué)性能試驗研究[D];北京交通大學(xué);2012年

4 林勇;早期預(yù)測混凝土強度的理論分析和試驗研究[D];天津大學(xué);2008年

5 張麒;混凝土早期損傷數(shù)值分析[D];同濟大學(xué);2008年

6 李曉芬;早齡期商品混凝土力學(xué)性能的試驗研究[D];鄭州大學(xué);2005年

7 沈毅;早齡期混凝土若干性能的研究[D];浙江大學(xué);2004年

8 馬智英;鋼纖維混凝土早期力學(xué)性能發(fā)展規(guī)律的試驗研究[D];北京工業(yè)大學(xué);2003年

，

本文編號：2049179