机制砂中石粉对混凝土耐久性的影响研究

试验研究了石粉含量对不同强度等级机制砂混凝土强度、抗氯离子渗透性能和抗冻性能的影响。结果表明:石粉对低强和高强混凝土的影响不完全相同,对于低强度机制砂混凝土,随着机制砂中石粉含量的增加,混凝土的抗氯离子渗透性能提高,而抗冻性能降低,尤其是当石粉含量高于10%(石粉与水泥体积比超过1∶3.47)时,混凝土劣化明显;但对于高强混凝土而言,仅当石粉含量大于7%时,石粉使混凝土工作性出现劣化,而对于抗氯离子渗透性能,抗冻性能等耐久性,石粉含量从3.5%提高到14%,均未使高强机制砂混凝土出现劣化现象。

EFFECTS OF MICRO-FINES ON DURABILITY OF MANUFACTURED SAND CONCRETE

It was investigated that the effects of the different content micro-fines in manufactured sand on the compressive strength,permeability of chloride ion and resistance to freezing in different strength grade concrete.The result shows that the effects of the micro-fines on low and high strength concrete are not completely the same.To the low strength concrete,the resistance to chloride ion permeating of concrete is improved with the micro-fines content,but the resistance to freezing deduces.Especially when the micro-fines content is higher than 10%(ratio by volume of micro-fines and cement exceeds 1∶3.47),the degradation of manufactured-sand concrete is obvious;but to the high strength concrete,the workability becomes bad when the micro-fines content is higher than 7%.Whereas,to the durability of concrete,such as resistance to chloride ion permeating and resistance to freezing etc.,there is no degradation in the high strength manufactured sand concrete when the micro fines content rises from 3.5% to 14%.