石灰石粉和粉煤灰对混凝土强度和耐久性的影响

Effects of Limestone Powder and Fly Ash on Concrete Strength and Durability

采用少量熟料与超细石灰石粉和劣质粉煤灰复合制备混凝土,并研究了石灰石粉和粉煤灰对混凝土的强度和耐久性的影响。研究表明:用少量熟料与超细石灰石粉和劣质粉煤灰复合能够制备出中低强度等级的混凝土,并且混凝土的强度随着龄期不断增长。当混合材料(包括石灰石粉和粉煤灰)掺量为60%时,石灰石粉和粉煤灰比例为8:2试样的180d抗压强度最大,超过50MPa;当混合材料料掺量为70%时,石灰石粉和粉煤灰比例为7:3的试样的180d抗压强度最高,超过了40MPa。混凝土的抗碳化性均较好,除了混合材掺量为80%的复合胶凝材料制备的混凝土的抗冻性和抗氯离子渗透性较差外,其他试样均较好;混凝土经过180d养护后的抗氯离子渗透能力均得到显著增强。

The concrete is prepared by compound cementitous material with less clinker and limestone powder and inferior fly ash.Effects of limestone powder and inferior fly ash on concrete strength and durability are studied.The results show that the middle-low strength grade concrete can be prepared by compound cementitous material compounded with clinker and limestone powder and fly ash,and its strength constantly increase with time.If the mixture dosage is 60%,when the ratio of limestone powder and fly ash is 8：2,the compressive strength which is greater than 50MPa at 180 days is the highest.If the mixture dosage is 70%,when the ratio of limestone powder and fly ash is 7：3,the compressive strength which is greater than 40MPa at 180 days is the highest.All concrete have fine resistance to carbonation,and all concrete except the concrete which is prepared with 80% mixture dosage have good chloride-penetration resistance and frost resistance.The chloride-penetration resistance of all concrete is significantly enhanced after 180 days curing.