粉煤灰对碾压混凝土耐久性的影响

用于大体积混凝土工程的碾压混凝土，其耐久性好坏直接关系到重大工程的使用及寿命。从抗渗性、抗冻性、抗冲磨性、抗碳化性及抗化学侵蚀性等方面研究了粉煤灰对碾压混凝土耐久性的影响。结果表明：（1）粉煤灰能提高碾压混凝土后期的抗渗性；（2）在碾压混凝土中增加粉煤灰的用量，提高胶凝材料的总量，从而降低混凝土的水灰比，能提高碾压混凝土抗冻性：（3）粉煤灰掺量不大于15％时，粉煤灰掺量对碾压混凝土的抗冲磨性能影响甚微；（4）粉煤灰掺量不大于50％时，经碳化后混凝土的抗压强度反而有所提高；（5）碾压混凝土的水化产物长期稳定性较好，且因有粉煤灰的二次水化消耗了部分Ca（OH）2，故其抗镁盐及硫酸盐侵蚀的能力较强。

Influence of fly ash on durability of roll compacted concrete

Performance and lifespan of great project depend on the durability of compacted concrete used in bulky project. The infulence of fly ash on durability of compacted concrete was studied from aspects of impermeability, freeze resistance, impact resistance, carbonisation resistance and chemical resistance. The results are as follows: (1) fly ash can improve late impermeability of compacted concrete; (2) it can enhance freeze resistance of compacted concrete that enlarging fly ash and cementing material content in concrete to lower w/c ratio;(3) if fly ash content is higher than 15%, influence of fly ash on impact resistance of concrete is unnoted; (4) if fly ash content is not higher than 50%, compress strength of cabonisated concrete increased at a certait extent instead; (5) hydrate of compacted concrete long-term stability is preferable and magnesite and sulphate corrasion resistance of the concrete is great since second hydration of fly ash comsume some of Ca(OH)2.