摘要
超高性能混凝土具有高密实度、超高强度和高韧性的特点,是建设超高强射线屏蔽建筑的理想材料,掺入少量重骨料后表观密度较小,且其胶凝材料用量高,水化放热大。因此,采用重晶石粉取代部分胶凝材料(替代粉煤灰微珠体积比例为0%、10%、20%、30%、40%)制备了防辐射超高性能混凝土。结果表明,随着重晶石粉取代粉煤灰微珠量的增加,混凝土工作性能和力学性能逐渐降低,表观密度逐渐增加,水化放热量先增加后逐渐降低,水化放热量在取代量为10%时达到最大,3d的水化热值为139.526J/g。综合考虑,推荐重晶石粉取代粉煤灰微珠量为20%,坍落度/扩展度达到255mm/620mm,表观密度为2660kg/m^(3),28d抗压强度135.4MPa,28d抗折强度25.9MPa,3d的水化放热量为121.650J/g,长期耐久性能良好,^(137)Cs放射源(0.662MeV)线性吸收系数为0.182cm^(-1),预湿高钛重矿渣砂的内养护作用促进了周围水泥浆体的水化,从而加强了界面过渡区,显著提高了多孔集料制备的UHPC的力学性能和耐久性能。
Ultra-high performance concrete has many good characteristics of high density,high strength and high toughness.It is an ideal material for the construction of ultra-high strength ray-shielding building.After adding a small amount of heavy aggregate,the apparent density is small,and the amount of cementitious material is high,and the hydration heat release is large.Therefore,barite powder was used to replace part of cementitious materials(the volume ratio of fly ash beads is 0%,10%,20%,30%,and 40%)to prepare radiation-shielding ultra-high performance concrete.The experimental results show that with the increase of barite powder replacing fly ash beads,the working performance and mechanical properties of UHPC gradually decrease,the apparent density gradually increases,and the hydration heat release first increases and then gradually decreases.The hydration heat release reaches the maximum when the replacement amount is 10%,and the 3 dhydration heat value is 139.526 J/g.Based on the comprehensive consideration,it is recommended that the amount of barite powder instead of fly ash beads is 20%,slump/expansion is 255 mm/620 mm,apparent density is 2660 kg/m^(3),28 dcompressive strength is 135.4 MPa,28 dflexural strength is 25.9 MPa,3 dhydration heat release is 121.650 J/g,long-term durability is good,and linear absorption coefficient of^(137)Cs radioactive source(0.662 MeV)is 0.182 cm^(-1).The internal curing effect of pre-wetted high titanium heavy slag sand can promote the hydration of surrounding cement paste,strengthen the interfacial transition zone,and significantly improve the mechanical properties and durability of UHPC prepared by porous aggregate.
作者
付浩兵
丁庆军
李宏斌
FU Hao-bing;DING Qing-jun;LI Hong-bin(Poly Changda Engineering Co Ltd,Guangzhou 510620,China;State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China)
出处
《武汉理工大学学报》
CAS
2021年第5期9-15,共7页
Journal of Wuhan University of Technology
关键词
重晶石粉
防辐射超高性能混凝土
防辐射性能
微观结构
barite powder
radiation-shielding ultra-high performance concrete
performance
microstructure
