再生粗集料砂浆附着率测试方法对比试验研究

Test method comparison of mortar adhesive rate of recycle coarse aggregate

研究采用旧桥拆除的梁板和防撞混凝土护栏2种强度等级的混凝土分别进行破碎得到2种再生粗集料,用酸溶液浸泡法、加热法、洛杉矶磨耗法以及改进的洛杉矶磨耗法分别测试这2种再生粗集料的砂浆附着率,结果表明,酸溶液浸泡法受原混凝土强度等级影响较大,强度等级高的混凝土破碎得到的再生粗集料砂浆附着率较大;加热法、洛杉矶磨耗法可以反映出砂浆与集料附着的紧密程度,加热法得到的砂浆附着率最低,洛杉矶磨耗法测得的砂浆附着率最高,而采用去掉钢球且增加磨耗转数的改进洛杉矶磨耗法可以在基本不影响原生集料形貌的基础上最大程度剥离掉砂浆,测得的砂浆附着率更准确。

Two types of recycled coarse aggregates were obtained by crushing concrete of two strength grades,namely the beam slab removed from the old bridge and the anti-collision concrete guardrail. The mortar adhesive rates of these two types of recycled coarse aggregates were tested by dipping in acid solution,heating,abrasion and improving abrasion respectively. The result shows that the method of dipping in acid solution is easily affected by original concrete design compressive strength. The value of mortar adhesive rate from high strength concrete is higher than the one form low strength concrete. Heating and abrasion methods can re-flect the adhere performance between mortar and nature aggregate. The value of mortar adhesive rate tested by heating method is the lowest. The value tested by abrasion method is the highest. The improving abrasion method of removing the steel ball and in-creasing the number of abrasion revolutions is the most accurate test method because it can not only peel the mortar as much as possible,but also can keep the nature aggregate original style.