摘要
为探索矿物掺合料粒度分布差异对喷射混凝土抗硫酸盐侵蚀性能的影响,将矿渣、粉煤灰与普通硅酸盐水泥进行组合,以净浆流动度表征净浆的工作性,对矿物掺合料的颗粒粒度分布进行了评价。通过干湿循环硫酸盐侵蚀试验,以质量变化率、相对动弹模量、表观状态作为评价指标,分析比较了喷射混凝土在硫酸盐侵蚀作用下的性能劣化规律。结合微观形貌观察,揭示了矿物掺合料粒度分布对喷射混凝土性能的影响机理。研究结果表明,不同矿渣和粉煤灰颗粒组合的净浆流动性存在较大差异,I级粉煤灰对提高流动性起了关键性作用。矿物掺合料粒度分布不同,其在硫酸盐侵蚀作用下的性能变化规律也不同。经历180个干湿循环后,B95-II和D105-II组试件质量较初始质量分别下降了6.2%和5.3%,相对动弹模量已分别降至0.65和0.58,损伤劣化严重。A95-I组和C105-I组混凝土试件质量和相对动弹模量变化较为缓慢,尤其是A95-I组,180次循环后质量损失仅为3.1%,相对动弹模量仍保持在0.85。微观测试结果表明,矿物掺合料的粒度分布影响了喷射混凝土内部结构,从而对其抗硫酸盐侵蚀性能产生了重要影响,为宏观性能试验结果提供了良好的佐证。
To explore the influence of the particle size distribution difference of mineral admixture on the sulfate resistance of shotcrete,slag,fly ash and ordinary Portland cement were combined to characterize the workability of the slurry by the fluidity of the slurry,and the particle size distribution of mineral admixture was evaluated.Through the dry wet cyclic sulfate erosion test,taking the mass change rate,relative dynamic elastic modulus and apparent state as the evaluation indexes,the performance deterioration law of shotcrete under sulfate erosion was analyzed and compared.Combined with the microstructure test and analysis,the influence mechanism of particle size distribution of mineral admixture on the performance of shotcrete was revealed.The results show that there are great differences in the fluidity of net slurry with different combinations of slag and fly ash particles,and grade I fly ash plays a key role in improving the fluidity.With different particle size distribution of mineral admixtures,their performance changes under sulfate attack are also different.After 180 times dry wet cycles,the mass of B95-II and D105-II specimens decreased by 6.2%and 5.3%respectively compared with the initial mass,and the relative dynamic elastic modulus decreased to 0.65 and 0.58 respectively.The mass and relative dynamic modulus of concrete specimens in the A95-I and C105-I groups change slowly,especially in the A95-I group,the mass loss is only 3.1%after 180 times cycles,and the relative dynamic modulus is still 0.85.The micro test results show that the particle size distribution of mineral admixtures affects the internal structure of shotcrete,which has an important impact on its sulfate resistance,which provides good evidence for the macro performance test results.
作者
汤建华
贾飞
潘慧敏
赵翔
王选明
石超
TANG Jianhua;JIA Fei;PAN Huimin;ZHAO Xiang;WANG Xuanming;SHI Chao(CCCC Road Bridge North China Engineering Co.,Ltd.,Beijing 101100,China;College of Civil Engineering and Mechanics,Yanshan University,Qinhuangdao 066004,China)
出处
《混凝土》
CAS
北大核心
2022年第6期61-66,共6页
Concrete
基金
国家自然科学基金(51608469,52078450)
交通部平安百年品质工程示范项目(京秦高速公路遵化至秦皇岛段)。
关键词
喷射混凝土
隧道
矿物掺合料
粒度分布
硫酸盐侵蚀
shotcrete
tunnel
mineral admixtures
particle size distribution
sulfate attack
