【作者】 张建业；

【导师】 黄东升；

【作者基本信息】 南京航空航天大学 ， 结构工程， 2007， 硕士

【摘要】 绿色高耐久性混凝土(Green high durable concrete,GHDC),是近年来在绿色高性能混凝土(GHPC)、高性能膨胀混凝土、混杂纤维增强混凝土的基础上,开发的一种既具有高耐久性(高的抗渗性、抗冻性及抗腐蚀性)、高工作性和经济适用性,又具有保护环境、节约能源、有益于社会可持续发展的新型混凝土。本文首先制备了7大系列19组配合比的混凝土,并依据塑性收缩开裂试验的结果,优选出GHDC的典型配合比,制备出不同强度等级的GHDC。针对当前混凝土耐久性的研究动态,在冻融循环作用、35%外部弯曲应力、NaCl溶液侵蚀、MgSO4溶液侵蚀、(MgCl2和Na2SO4 )复合溶液侵蚀等因素作用下,进行了混凝土在单一冻融、双重(冻融+35%弯曲应力、冻融+10%NaCl、冻融+5%MgSO4、冻融+5%MgCl2+5%Na2SO4)因素作用和多重(冻融+35%弯曲应力+10%NaCl、冻融+35%弯曲应力+5%MgSO4、冻融+35%弯曲应力+5%MgCl2+5%Na2SO4)因素作用下的抗冻性试验。主要研究了大掺量矿物掺和料(粉煤灰、矿渣和硅灰)、水胶比、外加剂(高效引气剂、膨胀剂)多元复合,纤维混杂增强、腐蚀溶液和外部弯曲应力等因素对混凝土冻融损伤产生的影响,并分析冻融损伤的发生、发展和抑制规律,对抑制混凝土冻融损伤的规律进行了实验研究。主要得出如下结论:(1) 35%外部弯曲应力加速了混凝土的冻融劣化过程和冻融损伤程度,在实际工程混凝土使用环境中应充分重视应力的作用。(2)混凝土在盐溶液中的双重及多重因素冻融损伤程度均低于单一冻融因素损伤的程度;混凝土在不同盐环境下的冻融寿命长短依次是:复合溶液(5%MgCl2+5%Na2SO4 )﹥5%MgSO4﹥10%NaCl。(3)水胶比减小和大掺量矿物掺和料(粉煤灰+矿渣+硅灰),对在(冻融+10%NaCl)和(冻融+5%MgSO4)双重因素作用下抑制混凝土冻融损伤的效果不显著;对在单一冻融因素、(冻融+应力)和(冻融+复合溶液)作用下,可以显著改善混凝土的抗冻性和抗腐蚀性,混凝土的抗冻性和抗腐蚀性都得到一定程度的改善。(4)外加剂(膨胀剂+引气剂)与混杂纤维增强的多元复合产生了抑制冻融损伤的复合效应,抑制混凝土冻融损伤的效果非常明显,使混凝土抵抗冻融损伤的能力更强,使混凝土抗冻融损伤的寿命大大提高。(5)通过实验数据的回归分析,获得了试验条件下混凝土冻融损伤失效过程的数学模型。(6)实际应用中,应根据各种措施的特点,对于不同冻融损伤环境选用不同的措施,掺加不同的外加剂,采用合适的纤维混杂比例,以达到抑制冻融损伤、提高混凝土抗冻性的最佳效果。更多还原

【Abstract】 Green high durable concrete (GHDC), was opened out as a new concrete on the base of in recent years Green high performance concrete (GHPC), the high-performance expansion concrete(HPEC), hybrid fiber-reinforce concrete(HFRC), which was not only a high-durability (high impermeability、high frost resistance and high attack resistance), high work and high economic applicability, but also to protect the environment and economize energy, benefit to sustainable social development.In this paper seven large series with more than 19 kinds of concrete were prepared. Firstly we choose GHDC optimized mix of classic and open out different grades of GHDC on the base of the outcome of the trial of plastic shrinkage cracks.The author carries through a trial of concrete durability aiming at the current developments in the freeze-thaw cycles, 35% of the external flexural stress, NaCl solution attack, MgSO4 solution attack,(MgCl2+Na2SO4) complex solution attack factors. The trial is a frost resistance test with single freeze-thaw, double factors role (freeze-thaw+35% external flexural stress、freeze-thaw+10%NaCl、freeze-thaw+5%MgSO4、freeze-thaw+5%MgCl2+5%Na2SO4) and multiple factors role(freeze-thaw+35% external flexural stress+10%NaCl、freeze-thaw+35% external flexural stress+5%MgSO4、freeze-thaw+35% external flexural stress+5%MgCl2+5%Na2SO4). The principal studies is the amount of mineral admixtures (fly ash, slag and silica fume), the water-cement ratio, attacking solution, external flexural stress, admixture (high-efficiency entrained air agent, expanders) composites, fiber hybrid reinforced concrete factors such as the impact and analysis of the freeze-thaw damage and inhibit the development of the law to contain the damage to the concrete experimental study of the laws.Main conclusions are drawn as follows:(1) 35% of external flexural stress accelerates the process of deterioration of concrete injury,the role of stress should be paid full attention to under the practical environment of using concrete.(2) The concrete freeze-thaw damage for double and multiple factors in the salt solution were lower than single to the injury factor; In different salt environment the concrete freeze-thaw followed by the length of life is:Complex solution (5%MgCl2+5%Na2SO4 )﹥5%MgSO4﹥10%NaCl.(3) Low water-cement ratio and the amount of mineral admixtures (fly ash+ slag+silica fume),in(freeze-thaw+10%NaCl and freeze-thaw+5%MgSO4) injury concrete under the inhibitory effect was not significant.In Single factor in the freeze-thaw、(freeze-thaw+stress)、(freeze-thaw+complex solution) following attack, significantly improving the overall frost resistance concrete and attack resistance. Frost resistance concrete and attack resistance has been improved to a certain extent.(4) Admixture (expanders+entrained air agent) and the hybrid fiber-reinforced composites produced a composite effect of inhibiting the injury, concrete curb injuries are very obvious, the stronger resistance concrete, concrete anti-injury life greatly improved.(5) Through regression analysis of the experimental data the mathematical model of concrete is obtained by freeze-thaw damage and failure of the process of testing conditions.(6) In practical application, accordance with the characteristics of various measures, different measures for different damage environmental shoud be taken, such as mixing different additives, using the appropriate proportion of hybrid fiber to inhibit injury, is the best results.更多还原