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利用双掺技术可以改善混凝土抗侵蚀性能.试验就双掺成分之一的粉煤灰用低质粉煤灰代替配制大掺量低质粉煤灰混凝土,在强度测试之前利用CTS25型非金属超声波检测仪进行无损检测,并利用热分析(DTA)和扫描电子显微镜(SEM)对标准养护和受盐酸侵蚀的混凝土水化进程、水化产物组成与数量的变化和微观结构与形貌等方面进行较深入地分析与研究.结果表明,超声波检测结果能较好地反映混凝土的密实程度或强度变化;大掺量低质粉煤灰混凝土在盐酸中浸泡至90d,抗蚀系数除A-4,B-4之外均大于0 80,说明低质粉煤灰大量掺入混凝土改善了抗盐酸侵蚀性能,其原因是减少水泥用量,粉煤灰吸收并反应水泥水化产生的Ca(OH)2,以及利用粉煤灰形态效应、微集料效应和与高效减水剂的双掺作用.
The use of double-doped technology can improve the corrosion resistance of concrete.For the test of double admixture of fly ash with low-quality fly ash instead of the preparation of high-volume low-fly ash concrete, strength testing before using CTS25 non-metallic ultrasonic The detector was used for non-destructive testing. Thermal analysis (DTA) and scanning electron microscopy (SEM) were performed on standard curing and concrete structures affected by hydrochloric acid hydration process, composition and amount of hydration products, microstructure and morphology The results show that the results of ultrasonic testing can better reflect the density or strength of concrete. High-volume low-fly ash concrete immersed in hydrochloric acid for 90 days, the corrosion resistance coefficient except A-4, B-4 are greater than 0 80, indicating a large number of low-quality fly ash mixed with concrete to improve the anti-hydrochloric acid corrosion resistance, the reason is to reduce the amount of cement, fly ash absorption and reaction of cement hydration generated Ca (OH) 2 , As well as the use of fly ash morphological effects, micro-aggregate effect and superplasticizer double doping effect.