掺新型生态膨胀剂水泥浆体的膨胀性能研究

Research on the Expansion of Cement Paste Mixed with Ecological Expansive Agents

以菱镁矿、白云石尾矿为原料,经适宜工艺,制备了新型生态膨胀剂,用以补偿大体积混凝土由于温度应力引起的收缩。研究掺入不同配比的膨胀剂和粉煤灰的水泥浆体,在不同水化龄期的膨胀性能以及在20℃或60℃水中膨胀率的变化过程和趋势。结果表明:膨胀材料煅烧温度为950～1050℃,保温1～1.5 h,自然冷却。在膨胀源含量一定的情况下,CaO含量越高,早期膨胀率越大,后期膨胀率越小;MgO含量越高,早期膨胀率越小,后期膨胀率越大。水化温度越高,在相同龄期下水泥浆体膨胀率越大。粉煤灰对MgO和CaO膨胀均具有明显的抑制作用,且随着粉煤灰掺量的增加,抑制作用加强。

A novel ecological expansive agent was prepared railings. The agent is used for concrete to compensate the using magnesite railings and dolomite shrinkage of dam concrete caused by temperature stress. The expansion properties of paste mixed with different proportions of expansive agents and fly ash were investigated at different hydration ages, and the trend of expansion ratio changes occurred in water at 20 ℃ and 60℃ were also explored. Results showed that expansive agents is produced by burning at 950-1050℃, holding for 1-1.5 h, and natural cooling in air. When the amount of expansive agents is in certain circumstances, the higher CaO, the higher the early expansion is and the smaller the late expansion is, the higher MgO, the smaller the early expansion is and the higher the late expansion is. The higher the hydration temperature, the higher the expansion at the same age is. The expansion performance of MgO and CaO is suppressed by increasing quantity of fly ash.