复杂环境作用下纳米改性混凝土力学性能试验  

Experimental Study on Mechanical Properties of Nano Modified Concrete under Complex Environment

作　　者：王富奎 WANG Fukui(Henan Six Construction Group Co.,Ltd.,Luoyang 471000,China)

机构地区：[1]河南六建建筑集团有限公司,河南洛阳471000

出　　处：《粉煤灰综合利用》2022年第5期93-98,共6页Fly Ash Comprehensive Utilization

摘　　要：为了有效抑制混凝土在碱集料反应和碳化损伤共同作用下的损伤程度,向混凝土中掺入不同比例的纳米SiO_(2)和纳米Fe_(2)O_(3),进行纳米改性混凝土力学性能试验。结果表明:当掺入纳米材料后,混凝土的强度得到显著提升,28 d养护龄期下,掺入2%的纳米SiO_(2)和1%的纳米Fe_(2)O_(3)较普通混凝土强度提升14.9%和11.9%;碳化深度、膨胀率随纳米材料掺量的增大呈先减小后增大的变化特征,超声波速则是先增大后减小的变化特征,当纳米SiO_(2)掺量为2%或者纳米Fe_(2)O_(3)掺量为1%时,碳化深度和膨胀率最小,超声波速最大,混凝土抑制碱集料反应和碳化损伤的效果最好;纳米SiO_(2)对于混凝土抑制碱集料和碳化损伤的效果较纳米Fe_(2)O_(3)更好,前者将Ca(OH)晶体转化为强度更高的C-S-H凝胶,后者主要将Ca(OH)晶体转化为AFm相和AFt相水化产物。In order to effectively inhibit the damage degree of concrete under the combined action of alkali aggregate reaction and carbonation damage,nano SiO_(2)and nano Fe_(2)O_(3)with different proportions were added to the concrete to test the mechanical properties of nano modified concrete.The results show that when nano materials are added,the strength of concrete is significantly improved,at 28 days of curing age,the strength of concrete mixed with 2%nano SiO_(2)and 1%nano Fe_(2)O_(3)is 14.9% and 11.9% higher than that of ordinary concrete;The carbonation depth and expansion rate decrease first and then increase with the increase of nano material content,and the ultrasonic velocity increases first and then decreases.when the nano SiO_(2)content is 2% or the nano Fe_(2)O_(3)content is 1%,the carbonation depth and expansion rate are the smallest,the ultrasonic velocity is the largest,and the concrete has the best effect on inhibiting alkali aggregate reaction and carbonation damage;the effect of nano SiO_(2) on the inhibition of alkali aggregate and carbonation damage of concrete is better than that of nano Fe_(2)O_(3),the former transforms Ca(OH)crystal into C-S-H gel with higher intensity,and the latter mainly refers to the conversion of Ca(OH)crystal into AFm phase and AFt phase hydration product.

关 键 词：碱集料反应 碳化损伤作用 纳米SiO_(2) 纳米Fe_(2)O_(3) 强度 耐久性 

分 类 号：TU528[建筑科学—建筑技术科学]