钢筋限制条件下水泥浆体的开裂敏感性研究

为探讨钢筋限制条件下不同配合比水泥浆体的开裂敏感性,测试了水泥浆体的抗拉强度;利用水泥浆体试件轴心处放置的钢筋对浆体所产生的限制收缩作用,连续测试出钢筋的应变值,并计算得到钢筋的应力值.在一定应力范围内,基于钢筋应力与包裹钢筋的水泥石受限收缩应力相等假定,比较了水泥浆体中受限收缩应力与抗拉强度的大小.结果发现,在一定水胶比mW/mB范围内,增加水胶比会降低水泥浆体的开裂敏感性;水胶比相同时,粉煤灰的掺加会显著降低水泥浆体的开裂敏感性.

Study on Cracking Sensitivity of Cement Paste under the Restriction of Steel Bars

To investigate the cracking sensitivity of cement paste under the restriction of steel bars, the tensile strength of the cement paste with different mineral admixtures was tested. With steel bar embedded in each specimen to restrain the shrinkage of the cement paste, continuous strain values of steel bars were taken down, which were converted into the stress values of steel bars. Based on the assumption that the stress value of the steel bars equals to that of the cement paste wrapping around the steel bars within a certain stress, the shrinkage stress of the cement paste and its tensile strength were compared; the factors affecting the cracking sensitivity of cement paste were analyzed. The results show that, the paste cracking sensitivity will decrease with water to binder ratio mW/mB increasing in some range; when the mW/mB is same, the addition of fly ash also decrease the cracking sensitivity significantly.