泵送混凝土约束收缩开裂性能评价试验研究
|
摘要
现代混凝土结构中,泵送混凝土被大量使用。泵送混凝土使得施工输送混凝土能力大、速度快、效率高、缩短工期、降低费用,同时减轻工人的劳动强度。但是,泵送混凝土的特点也导致了工程出现一些问题,比如现浇楼板裂缝,已经成为常见的质量通病。
作为江苏省“六大人才高峰”资助项目(A类)“现代混凝土裂缝机理及成套控制技术”的一个子课题,本文运用圆环约束法试验装置,结合泵送混凝土的基本性能测试,分析泵送混凝土早期开裂性能。首先,测试龄期分别为1、2、3、5、7、14天的泵送混凝土抗拉强度、弹性模量,并用Origin7.5数据拟合软件进行分析,用公式表达混凝土抗拉强度、弹性模量随龄期发展曲线;弹性模量测试方法包括压力机测试和超声波测试,本文也分析了两种方法得到的试验结果之间的区别和联系。同时,模拟混凝土圆环中的混凝土干燥情况,测试泵送混凝土早期自由收缩,并用Origin7.5数据拟合软件拟合收缩随龄期变化曲线,得出泵送混凝土收缩随龄期发展公式。其次,运用圆环约束法试验装置,通过观测约束钢环内表面应变变化,衡量泵送混凝土约束收缩性能。最后,运用弹性力学方法,对混凝土约束收缩试验装置进行理论分析,计算泵送混凝土环中理论应力和实际应力的发展,并结合泵送混凝土的抗拉强度试验,评价泵送混凝土的约束收缩开裂可能性,以及泵送混凝土的应力松弛性能,实现泵送混凝土的早期开裂性能评价。
改变泵送混凝土的泵送剂掺量、单方混凝土用水量、水泥用量,本文设计了8个配合比的泵送混凝土,研究泵送剂掺量、用水量、水泥用量对泵送混凝土早期开裂性能的影响。研究发现:相对于基准混凝土,泵送剂掺量、用水量、水泥用量的改变,都会影响泵送混凝土的早期开裂性能。因此,选择合适的泵送剂掺量、用水量、水泥用量,可以有效控制泵送混凝土早期开裂。
Pumping concrete is very popular in the construction of modern concrete structures, it makes the construction more rapidly and more efficiently, and it can alleviate the labor intensity of the workers. Hoeever, pumping concrete brings on many problems to the projects, such as the early age cracking of cast-in-place floor, which has already become the common quality fault.By testing concrete with ring specimens and other tests for mechanical properties of pumping concrete, this paper analyzed early age cracking properties of pumping concrete.Firstly, the pumping concrete were tested at 1, 2, 3, 5, 7, and 14 days after casting to determine the splitting tensile strength and elastic modulus, and the data were analyzed using the software Origin 7.5. The relation between tensile strength and age of the concrete was described using formula gained from the analysis with Origin 7.5. At the same time, the pumping concrete specimens in the similar drying condition as the ring specimens were tested for early age free shrinkage. The data of shrinkage were analyzed by software Origin 7.5, and the relation between shrinkage and age was described in the form of a formula. Then, ring tests were used in this paper to measure the inside surface strain of the steel ring. At last, the test setting was theoretically analyzed by mechanics of elasticity, and the theoretical stress and actual stress of ring specimens were calculated. In combination with the test of tensile strength, evaluation on cracking potential and stress relaxation of ring specimens was made. With all the above, the evaluation on cracking characteristics of pumping concrete at early age is realized.Concrete specimens with different constituent materials were tested in this paper. Test result indicated that the quantity of pumping agent, water, and cement used in concrete influenced the cracking properties of pumping concrete. The quantity of pumping agent, water, and cement should be properly chosen in construction.
作为江苏省“六大人才高峰”资助项目(A类)“现代混凝土裂缝机理及成套控制技术”的一个子课题,本文运用圆环约束法试验装置,结合泵送混凝土的基本性能测试,分析泵送混凝土早期开裂性能。首先,测试龄期分别为1、2、3、5、7、14天的泵送混凝土抗拉强度、弹性模量,并用Origin7.5数据拟合软件进行分析,用公式表达混凝土抗拉强度、弹性模量随龄期发展曲线;弹性模量测试方法包括压力机测试和超声波测试,本文也分析了两种方法得到的试验结果之间的区别和联系。同时,模拟混凝土圆环中的混凝土干燥情况,测试泵送混凝土早期自由收缩,并用Origin7.5数据拟合软件拟合收缩随龄期变化曲线,得出泵送混凝土收缩随龄期发展公式。其次,运用圆环约束法试验装置,通过观测约束钢环内表面应变变化,衡量泵送混凝土约束收缩性能。最后,运用弹性力学方法,对混凝土约束收缩试验装置进行理论分析,计算泵送混凝土环中理论应力和实际应力的发展,并结合泵送混凝土的抗拉强度试验,评价泵送混凝土的约束收缩开裂可能性,以及泵送混凝土的应力松弛性能,实现泵送混凝土的早期开裂性能评价。
改变泵送混凝土的泵送剂掺量、单方混凝土用水量、水泥用量,本文设计了8个配合比的泵送混凝土,研究泵送剂掺量、用水量、水泥用量对泵送混凝土早期开裂性能的影响。研究发现:相对于基准混凝土,泵送剂掺量、用水量、水泥用量的改变,都会影响泵送混凝土的早期开裂性能。因此,选择合适的泵送剂掺量、用水量、水泥用量,可以有效控制泵送混凝土早期开裂。
Pumping concrete is very popular in the construction of modern concrete structures, it makes the construction more rapidly and more efficiently, and it can alleviate the labor intensity of the workers. Hoeever, pumping concrete brings on many problems to the projects, such as the early age cracking of cast-in-place floor, which has already become the common quality fault.By testing concrete with ring specimens and other tests for mechanical properties of pumping concrete, this paper analyzed early age cracking properties of pumping concrete.Firstly, the pumping concrete were tested at 1, 2, 3, 5, 7, and 14 days after casting to determine the splitting tensile strength and elastic modulus, and the data were analyzed using the software Origin 7.5. The relation between tensile strength and age of the concrete was described using formula gained from the analysis with Origin 7.5. At the same time, the pumping concrete specimens in the similar drying condition as the ring specimens were tested for early age free shrinkage. The data of shrinkage were analyzed by software Origin 7.5, and the relation between shrinkage and age was described in the form of a formula. Then, ring tests were used in this paper to measure the inside surface strain of the steel ring. At last, the test setting was theoretically analyzed by mechanics of elasticity, and the theoretical stress and actual stress of ring specimens were calculated. In combination with the test of tensile strength, evaluation on cracking potential and stress relaxation of ring specimens was made. With all the above, the evaluation on cracking characteristics of pumping concrete at early age is realized.Concrete specimens with different constituent materials were tested in this paper. Test result indicated that the quantity of pumping agent, water, and cement used in concrete influenced the cracking properties of pumping concrete. The quantity of pumping agent, water, and cement should be properly chosen in construction.
引文
[1] 陈德育.泵送混凝土现浇楼板裂缝原因分析及预防措施.混凝土与水泥制品,2002,8(4):44-46
[2] 徐伟,任洪峰等.商品混凝土的材料性能对混凝土早期裂缝的影响分析.建筑施工,2001,23(3):330-332
[3] 李元豹.泵送混凝土概述及其应用.铁道标准设计,1994,53(07):17-20
[4] Grzyboeski, M., and Shah S. P.. A Method to Predict Shrinkage Cracking in Fiber Reinforced Concrete. Magazine of Concrete Research, 1989, 41(148):125-135
[5] Surendra P. Shah, Chengsheng Ouyang. A Method to Predict Shrinkage Cracking of Concrete. ACI Materials Journal, 1998, 74(4): 339-346
[6] 混凝土泵送技术规程(JGJ/T10-95)
[7] 葛兆明,陈敏等.几个重要因素对高强泵送混凝土的影响.混凝土,2000,3(02):25-27
[8] Salah A. Altoubat, David A. Lange. Creep, Shrinkage, and Cracking of Restrained Concrete at Early Age. ACI Materials Journal, 2001, 98(4):323-331
[9] 林志海,覃维祖等.混凝土早期应力发展与抗裂性能评价.建筑技术,2003,1(34):34-35
[10] M. Sule, K. van Breugel. The effect of reinforcement on early-age cracking due to autogenous shrinkage and thermal sffects. Cement & Concrete Composites, 2004, 26(3):581-587
[11] J. A. Almudaiheem. An Improved Model to Predic The ultimate Drying Shrinkage of Concrete. Magazine of Concrete Research, 1992, 44(159): 81-85
[12] 欧阳泳,姚立宁等.碳/芳纶纤微混凝土温度变形控制机理的研究.广东工业大学学报,2002,1(19):48-52
[13] Kraal, P. A Proposed Test to Determing the Cracking Potential due to Drying Shrinkage of Concrete. Concrete Construction, 1985, 30(9):775-778
[14] 巴恒静,高小建.约束条件下高性能混凝土的早期开裂.混凝土,2002,5(151):3-6
[15] 高小建,何忠茂等.周边约束状态下板式混凝土早期开裂及收缩应变的分布.硅酸盐学报,2004,3(32):334-339
[16] 巴恒静,刘志国等.硫酸钠掺量对混凝土早期收缩开裂的影响.硅酸盐学报,2005,1 (33):36-41
[17] 马一平,谈慕华等.聚冈烯纤维水泥基复合材料物理力学性能研究.建筑材料学报,2000,1(3):48-52
[18] 张礼利,谈慕华等.PP纤维水泥界面粘结与抗干缩开裂性能研究.建筑材料学报,2001,2(4):17-21
[19] 马一平,谈慕华等.聚丙烯纤维几何形态对水泥砂浆塑性干缩开裂性能的影响.混凝土与水泥制品,2001,2(3):38-40
[20] 马一平,朱蓓蓉等.纤维参数对水泥砂浆塑性收缩开裂性能的影响.建筑材料学报,2002,3(5):220-224
[21] 马一平,朱蓓蓉等.水泥砂浆塑性收缩开裂试验条仆的研究.建筑材料学报,2002,4(5):399-404
[22] 马一平.朱蓓蓉等.水泥砂浆塑性抗拉强度与收缩开裂的关系.建筑材料学报,2003,1(6),pp.20-24
[23] 马一平,谈慕华等.水泥基体参数对砂浆塑性收缩开裂性能的影响.建筑材料学报,2002,2(5):171-175
[24] 王川,杨长辉等.矿渣和粉煤灰对混凝土塑性收缩裂缝的影响.混凝土,2002,11(157):45-48
[25] 杨长辉,王川等.水灰比对混凝土塑性收缩裂缝的影响.重庆建筑大学学报,2003,2(25):77-81
[26] 吴芳,蔡贵生等.聚丙烯纤维控制特细砂混凝土塑性收缩裂缝试验研究.重庆建筑大学学报,2003,5(25):81-86
[27] 杨长辉,孙大明等.水灰比对轻骨料混凝土塑性收缩裂缝的影响.重庆建筑大学学报,2004,3(26):85-88
[28] 孙大明,何兵等.粗骨料对轻骨料混凝土塑性收缩裂缝的影响.重庆建筑大学学报,2004,4(26):88-91
[29] Richard, w., Burrows,. The Visible and Invisible Cracking of Concrete. 1998:1-5
[30] 马丽媛.高强混凝土收缩开裂的研究[D].中国建筑材料科学研究院硕士学位论文,2001
[31] 陈翠红,王元等.大流态混凝土早期裂缝原因分析及控制措施.混凝土,2003,5(163):33-34
[32] 郑翥鹏.高强与高性能混凝土的抗裂影响因素及理论分析[D].福州大学硕土学位论文,2002
[33] 郑建岚,罗素蓉等.高强与高性能混凝土的收缩与开裂.安全与环境学报,2004,2(4):47-50
[34] 桂海清.混凝土早期收缩与抗裂性能试验研究[D].浙江大学硕士学位论文,2004
[35] Frank Collins, J. G. Sanjayan. Cracking tendency of alkali-activated slag concrete subjected to restrained shrinkage. Cement and Concrete Research, 2000, 30(3):791-798
[36] David A. Whiting, Rachel J. Detwiler. Cracking Tendency and Drying Shrinkage of Silica Fume Concrete for Bridge Deck Applications. ACI Materials Journal, 2000, 78(1):71-77
[37] J. Branch, A. Rawling, D. J. Hannant. The Effect of Fiber on the Plastic Shrinkage Cracking of High Strenght Concrete. Materials and Structures, 2002, 35(4): 189-194
[38] Heather T. See, Emmanuel K. Attiogbe. Shrinkage Cracking Characteristics of Concrete Using Ring Specimens. ACI Materials Journal, 2003, 89(2):239-245
[39] Mehmet Gesoglu, Turan Ozturan. Shrinkage Cracking of Lightweight Concrete Made with Cold-Bonded Fly Ash Aggregates. Cement and Concrete Research, 2004, 34(1):1121-1130
[40] Thomas Voigt, Van K. Bui, Surendra P. Shah. Drying Shrinkage of Concrete Reinforced with Fibers and Weided-Wire Fabric. ACI Materials Journal, 2004, 89(3):233-241
[41] Romildo D. Toledo Filho, Khosrow Ghavami. Free, restrained and drying shrinkage of cement mortar composites reinforced with vegetable fibers. Cement & Concrete Composites, 2005, 27(2):537-546
[42] Standard Practice for Estimating the Cracking Tendency of Concrete, AASHTO Designation, pp. 34-99
[43] David A. Whiting;Rachel J. Detwiler;and Eric S. Lagergren. Cracking Tendency and Drying Shrinkage of Silica Fume Concrete for Bridge Deck Application. ACI Materials Journal, 2000, 74(2):71-77
[44] Heather T. See;Emmanuel K. Attiogbe;and Matthew A. Miltenberger. Shrinkage Cracking Characteristics of Concrete Using Ring Specimens. ACI Materials Journal, 2003, 85(2):239-245
[45] Akhter B. Hossain, Jason Weiss. Assessing Residual Stress Development and Stress Relaxation in Restrained Concrete Ring Specimens. Cement and Concrete Composites 2004, 26(1): 531-540
[46] P.A Dahl. Influence of fiber reinforcement on plastic shrinkage and cracking. Elsevier Applied Science, 1986, 32(1):435-441
[47] Kovler K.;Sikuler J.;and Bentur A.. Restrained Shrinkage Tests of Fiber-Reinforced Concrete Ring Specimens: Effects of Core Thermal Expansion. Material s and Structures, 1993, 26(158): 231-237
[48] Zhen he;Xiangming Zhou: and Zongjin Li. New Experimental Method for studying Early-age cracking of Cement-Based Materials. ACI Material Journal, 2004, 85(1):409-415
[49] Akhter B. Hossain, Jason Weiss. Assessing residual stress development and stress relaxation in restrained concrete ring specimens. Cement & Concrete Composites, 2004, 26(1): 531-540
[50] 黄政宇,赵俭英.混凝土配合比速查手册.中国建筑工业出版社,2002 (第二版):136
[51] Miroslaw Grzybowski, and Surendra P. Shah. Shrinkage Cracking of Fiber- Reinforced Concrete. ACI Materials. Journal, 1990, 43(3):138-148
[52] S. P Shah;Yang W: Weiss W. J. Influence of Specimen Size/Geometry on Shrinkage Cracking of Rings. Journal of Engineering Mechanics, 2000, 32(1):93-101
[53] Wee, T.H.;Lu, H.R.;and Swaddiwudhipong, S.. Tensile Strain Cappcity of Concrete under Various States of Stress. Magazine of Concrete Research, 2000, 52(3): 185-193
[2] 徐伟,任洪峰等.商品混凝土的材料性能对混凝土早期裂缝的影响分析.建筑施工,2001,23(3):330-332
[3] 李元豹.泵送混凝土概述及其应用.铁道标准设计,1994,53(07):17-20
[4] Grzyboeski, M., and Shah S. P.. A Method to Predict Shrinkage Cracking in Fiber Reinforced Concrete. Magazine of Concrete Research, 1989, 41(148):125-135
[5] Surendra P. Shah, Chengsheng Ouyang. A Method to Predict Shrinkage Cracking of Concrete. ACI Materials Journal, 1998, 74(4): 339-346
[6] 混凝土泵送技术规程(JGJ/T10-95)
[7] 葛兆明,陈敏等.几个重要因素对高强泵送混凝土的影响.混凝土,2000,3(02):25-27
[8] Salah A. Altoubat, David A. Lange. Creep, Shrinkage, and Cracking of Restrained Concrete at Early Age. ACI Materials Journal, 2001, 98(4):323-331
[9] 林志海,覃维祖等.混凝土早期应力发展与抗裂性能评价.建筑技术,2003,1(34):34-35
[10] M. Sule, K. van Breugel. The effect of reinforcement on early-age cracking due to autogenous shrinkage and thermal sffects. Cement & Concrete Composites, 2004, 26(3):581-587
[11] J. A. Almudaiheem. An Improved Model to Predic The ultimate Drying Shrinkage of Concrete. Magazine of Concrete Research, 1992, 44(159): 81-85
[12] 欧阳泳,姚立宁等.碳/芳纶纤微混凝土温度变形控制机理的研究.广东工业大学学报,2002,1(19):48-52
[13] Kraal, P. A Proposed Test to Determing the Cracking Potential due to Drying Shrinkage of Concrete. Concrete Construction, 1985, 30(9):775-778
[14] 巴恒静,高小建.约束条件下高性能混凝土的早期开裂.混凝土,2002,5(151):3-6
[15] 高小建,何忠茂等.周边约束状态下板式混凝土早期开裂及收缩应变的分布.硅酸盐学报,2004,3(32):334-339
[16] 巴恒静,刘志国等.硫酸钠掺量对混凝土早期收缩开裂的影响.硅酸盐学报,2005,1 (33):36-41
[17] 马一平,谈慕华等.聚冈烯纤维水泥基复合材料物理力学性能研究.建筑材料学报,2000,1(3):48-52
[18] 张礼利,谈慕华等.PP纤维水泥界面粘结与抗干缩开裂性能研究.建筑材料学报,2001,2(4):17-21
[19] 马一平,谈慕华等.聚丙烯纤维几何形态对水泥砂浆塑性干缩开裂性能的影响.混凝土与水泥制品,2001,2(3):38-40
[20] 马一平,朱蓓蓉等.纤维参数对水泥砂浆塑性收缩开裂性能的影响.建筑材料学报,2002,3(5):220-224
[21] 马一平,朱蓓蓉等.水泥砂浆塑性收缩开裂试验条仆的研究.建筑材料学报,2002,4(5):399-404
[22] 马一平.朱蓓蓉等.水泥砂浆塑性抗拉强度与收缩开裂的关系.建筑材料学报,2003,1(6),pp.20-24
[23] 马一平,谈慕华等.水泥基体参数对砂浆塑性收缩开裂性能的影响.建筑材料学报,2002,2(5):171-175
[24] 王川,杨长辉等.矿渣和粉煤灰对混凝土塑性收缩裂缝的影响.混凝土,2002,11(157):45-48
[25] 杨长辉,王川等.水灰比对混凝土塑性收缩裂缝的影响.重庆建筑大学学报,2003,2(25):77-81
[26] 吴芳,蔡贵生等.聚丙烯纤维控制特细砂混凝土塑性收缩裂缝试验研究.重庆建筑大学学报,2003,5(25):81-86
[27] 杨长辉,孙大明等.水灰比对轻骨料混凝土塑性收缩裂缝的影响.重庆建筑大学学报,2004,3(26):85-88
[28] 孙大明,何兵等.粗骨料对轻骨料混凝土塑性收缩裂缝的影响.重庆建筑大学学报,2004,4(26):88-91
[29] Richard, w., Burrows,. The Visible and Invisible Cracking of Concrete. 1998:1-5
[30] 马丽媛.高强混凝土收缩开裂的研究[D].中国建筑材料科学研究院硕士学位论文,2001
[31] 陈翠红,王元等.大流态混凝土早期裂缝原因分析及控制措施.混凝土,2003,5(163):33-34
[32] 郑翥鹏.高强与高性能混凝土的抗裂影响因素及理论分析[D].福州大学硕土学位论文,2002
[33] 郑建岚,罗素蓉等.高强与高性能混凝土的收缩与开裂.安全与环境学报,2004,2(4):47-50
[34] 桂海清.混凝土早期收缩与抗裂性能试验研究[D].浙江大学硕士学位论文,2004
[35] Frank Collins, J. G. Sanjayan. Cracking tendency of alkali-activated slag concrete subjected to restrained shrinkage. Cement and Concrete Research, 2000, 30(3):791-798
[36] David A. Whiting, Rachel J. Detwiler. Cracking Tendency and Drying Shrinkage of Silica Fume Concrete for Bridge Deck Applications. ACI Materials Journal, 2000, 78(1):71-77
[37] J. Branch, A. Rawling, D. J. Hannant. The Effect of Fiber on the Plastic Shrinkage Cracking of High Strenght Concrete. Materials and Structures, 2002, 35(4): 189-194
[38] Heather T. See, Emmanuel K. Attiogbe. Shrinkage Cracking Characteristics of Concrete Using Ring Specimens. ACI Materials Journal, 2003, 89(2):239-245
[39] Mehmet Gesoglu, Turan Ozturan. Shrinkage Cracking of Lightweight Concrete Made with Cold-Bonded Fly Ash Aggregates. Cement and Concrete Research, 2004, 34(1):1121-1130
[40] Thomas Voigt, Van K. Bui, Surendra P. Shah. Drying Shrinkage of Concrete Reinforced with Fibers and Weided-Wire Fabric. ACI Materials Journal, 2004, 89(3):233-241
[41] Romildo D. Toledo Filho, Khosrow Ghavami. Free, restrained and drying shrinkage of cement mortar composites reinforced with vegetable fibers. Cement & Concrete Composites, 2005, 27(2):537-546
[42] Standard Practice for Estimating the Cracking Tendency of Concrete, AASHTO Designation, pp. 34-99
[43] David A. Whiting;Rachel J. Detwiler;and Eric S. Lagergren. Cracking Tendency and Drying Shrinkage of Silica Fume Concrete for Bridge Deck Application. ACI Materials Journal, 2000, 74(2):71-77
[44] Heather T. See;Emmanuel K. Attiogbe;and Matthew A. Miltenberger. Shrinkage Cracking Characteristics of Concrete Using Ring Specimens. ACI Materials Journal, 2003, 85(2):239-245
[45] Akhter B. Hossain, Jason Weiss. Assessing Residual Stress Development and Stress Relaxation in Restrained Concrete Ring Specimens. Cement and Concrete Composites 2004, 26(1): 531-540
[46] P.A Dahl. Influence of fiber reinforcement on plastic shrinkage and cracking. Elsevier Applied Science, 1986, 32(1):435-441
[47] Kovler K.;Sikuler J.;and Bentur A.. Restrained Shrinkage Tests of Fiber-Reinforced Concrete Ring Specimens: Effects of Core Thermal Expansion. Material s and Structures, 1993, 26(158): 231-237
[48] Zhen he;Xiangming Zhou: and Zongjin Li. New Experimental Method for studying Early-age cracking of Cement-Based Materials. ACI Material Journal, 2004, 85(1):409-415
[49] Akhter B. Hossain, Jason Weiss. Assessing residual stress development and stress relaxation in restrained concrete ring specimens. Cement & Concrete Composites, 2004, 26(1): 531-540
[50] 黄政宇,赵俭英.混凝土配合比速查手册.中国建筑工业出版社,2002 (第二版):136
[51] Miroslaw Grzybowski, and Surendra P. Shah. Shrinkage Cracking of Fiber- Reinforced Concrete. ACI Materials. Journal, 1990, 43(3):138-148
[52] S. P Shah;Yang W: Weiss W. J. Influence of Specimen Size/Geometry on Shrinkage Cracking of Rings. Journal of Engineering Mechanics, 2000, 32(1):93-101
[53] Wee, T.H.;Lu, H.R.;and Swaddiwudhipong, S.. Tensile Strain Cappcity of Concrete under Various States of Stress. Magazine of Concrete Research, 2000, 52(3): 185-193