再生粗骨料混凝土耐久性试验研究

Experimental Study on the Durability of Recycled Coarse Aggregate Concrete

为验证掺加结晶型界面改性剂(IZM)改善再生粗骨料混凝土耐久性,对再生粗骨料混凝土进行收缩性、抗渗性、抗碳化性和抗化学侵蚀性等耐久性试验。结果表明:再生粗骨料混凝土的收缩较普通混凝土大,掺入IZM可使再生粗骨料混凝土的后期收缩降低;再生粗骨料混凝土的抗渗性能与普通混凝土相差不多,掺入IZM后再生粗骨料混凝土的抗渗性能变化不大,同时掺减水剂和IZM后再生粗骨料混凝土的抗渗标号是普通混凝土或再生粗骨料混凝土抗渗标号的2倍;再生粗骨料混凝土的抗碳化性较普通混凝土差,掺入IZM对再生粗骨料混凝土的抗碳化性能影响不大;在不同化学介质中浸泡28 d后,再生粗骨料混凝土的抗化学侵蚀性能较普通混凝土差,而掺入IZM对再生粗骨料混凝土的抗化学侵蚀性能有所提高。

To validate the effect of adding interface-zone modifying agent to improve the durability of recycled coarse aggregate concrete, an experimental study was carried out to investigate the durability of recycled concrete. The test results indicate that the shrinkage and carbonation depth of recycled concrete are larger than those of normal concrete. The interface-zone modifying agent has a positive influence on the shrinkage in later period but had little influence on the carbonation. The penetration resistance of recycled concrete is almost the same as that of the normal concrete. After simultaneously mixed with plasticizer and IZM, the recycled coarse aggregate concrete are more than double what the impermeability grade of the plain concrete or normal recycled coarse aggregate concrete is. Immersioned in different chemical medium for 28 d, the chemical erosion resistance of recycled coarse aggregate concrete is weaker than that of normal concrete. The incorporation of IZM improves the chemical erosion resistance of the recycled coarse aggregate concrete.