酸雨侵蚀作用下纤维混凝土损伤劣化规律研究

Research on damage and deterioration of fiber reinforced concrete under acid rain erosion

为了提高湖南酸雨地区建筑物的安全和使用寿命问题,试验研究了钢纤维-聚丙烯(PP)纤维混凝土在酸雨侵蚀作用下的耐久性能。以钢纤维体积掺量(2%,4%)、聚丙烯纤维体积掺量(0.05%,0.1%)作为影响因素进行模拟酸雨侵蚀试验,测量大循环周期内混凝土强度(抗压强度、抗拉强度)、质量以及相对动弹性模量变化规律,以此研究纤维对混凝土基体耐酸雨腐蚀性能的影响。试验结果表明钢纤维、PP纤维的掺入能够显著提高混凝土的强度。经10次酸雨侵蚀大循环后,纤维混凝土仍具有较高的耐久性能,其中掺入体积分数为4%钢纤维,体积分数为0.1%PP纤维可以有效抑制质量损失及动弹性模量下降速率。同时基于质量损失率和相对动弹性模量评价参数建立综合损伤变量公式用以评价纤维混凝土损伤程度,经多项式函数进行数据拟合验证,发现拟合度较高,可有效反映纤维混凝土在酸雨侵蚀作用下的损伤劣化规律。

In order to improve the safety and service life of buildings in Hunan acid rain area, the durability of steel fiber polypropylene(PP) fiber concrete under acid rain erosion was studied. Taking the steel fiber volume content(2%, 4%) and polypropylene fiber volume content(0.05%, 0.1%) as the influencing factors, the simulated acid rain corrosion test was carried out to measure the concrete strength(compressive strength, tensile strength), mass and relative dynamic modulus of elasticity in the large cycle, so as to study the influence of fiber on the acid rain corrosion resistance of concrete matrix. The results show that the steel fiber and PP fiber can significantly improve the strength of concrete. After 10 cycles of acid rain erosion, fiber reinforced concrete still has high durability, in which adding 4% steel fiber and 0.1% PP fiber can effectively inhibit the mass loss and the decline rate of dynamic elastic modulus. At the same time, based on the evaluation parameters of mass loss rate and relative dynamic elastic modulus, a comprehensive damage variable formula is established to evaluate the damage degree of fiber reinforced concrete. The polynomial function is used to fit the data, and it is found that the fitting degree is high, which can effectively reflect the damage deterioration law of fiber reinforced concrete under acid rain erosion.