摘要
以圆球型页岩陶粒为主要粗骨料，并用一级粉煤灰（FA（I））等体积取代30%普通砂，制备粉煤灰轻骨料混凝土.以超细粉煤灰（UFA）、硅灰（SF）分别等质量取代粉煤灰轻骨料混凝土10%-40%和5%-15%水泥，然后进行抗压强度试验、干湿循环试验、工业CT试验、压汞试验、动弹性模量试验，从混凝土抗蚀系数、孔隙率、动弹性模量等方面研究硫酸盐作用下粉煤灰轻骨料混凝土力学性能演变规律及微观结构变化情况.结果表明：在Na2SO4溶液浓度（质量分数）为0%-10%时干湿循环20次，混凝土抗压强度达到最高值，随后下降较快；在10% Na2SO4溶液中干湿循环50次，当UFA，SF取代率分别为20%,10%时，粉煤灰轻骨料混凝土抗蚀系数均达到最高值；掺UFA，SF粉煤灰轻骨料混凝土50-100nm孔所占体积分数明显增多，掺20%UFA和掺10%SF粉煤灰轻骨料混凝土〈100nm孔体积分数分别为普通混凝土的139，146倍；适量掺加UFA或SF能优化轻骨料砂浆界面过渡区微观结构，增强轻骨料砂浆界面黏结性能，延缓硫酸盐对粉煤灰轻骨料混凝土结构基体的进一步侵蚀.
Spherical shale haydite was selected as main coarse aggregate, while 30% ordinary sand was replaced by grade I fly ash of the same volume to prepare fly ash lightweight aggregate concrete. 10%-40%（by mass） or 5%15% cement of fly ash lightweight aggregate concrete were equivalently replaced by ultra fine fly ash（UFA） or silica fume（SF） respectively, the mechanical property evolution law and change of microstructure of fly ash lightweight aggregate concrete under sulfate attack were investigated in terms of corrosion resistance coefficient, porosity and dynamic elastic modulus of concrete, in which compressive strength test, drying wetting cycle test, industrial computed tomography test, mercury injection test and dynamic elastic modulus test were employed. As the research result shows, after a period of drying wetting cycle of 20 times with the Na2SO4 solution concentration（by mass） ranging from 0% to 10%, the compressive strength reaches the maximum value and then decreases fast; the corrosion resistance coefficients of fly ash lightweight aggregate concrete reach the maximum value when the replacement rate of UFA and SF are 20% and 10% respectively with drying wetting cycles of 50 times in 10% Na2SO4 solution. Meanwhile, the volume fractions of pores with size between 50nm and 100nm in fly ash lightweight aggregate concrete with UFA or SF added increase significantly. The volume fractions of pores with size less than 100nm in fly ash lightweight aggregate concrete with 20%UFA or 10%SF added are 139 times and 146 times that of ordinary concrete. Furthermore, the interfacial transition zone and the bond property between lightweight aggregate and mortar is improved, so that the further erosion by sulfate to the structure of fly ash lightweight aggregate concrete is delayed.
出处
《建筑材料学报》
EI
CAS
CSCD
北大核心
2014年第3期389-395,共7页
Journal of Building Materials
基金
国家自然科学基金资助项目(11072041)
高等学校博士学科点专项科研基金资助项目(20104316120001)
湖南省教育厅资助科研项目(11A005)
关键词
轻骨料混凝土
干湿循环
硫酸盐
抗压强度
动弹性模量
lightweight aggregate concrete（LWAC）
drying-wetting cycle
sulfate
compressive strength
dynamic elastic modulus
