Basic magnesium sulfate cement coral aggregate concrete(MCAC)is a new type of concrete consisting of basic magnesium sulfate cement,coarse coral aggregate,coral reef sand and seawater.The rebound hammer(RH),the ultras...Basic magnesium sulfate cement coral aggregate concrete(MCAC)is a new type of concrete consisting of basic magnesium sulfate cement,coarse coral aggregate,coral reef sand and seawater.The rebound hammer(RH),the ultrasonic pulse velocity(UPV)and the compressive strength(fcu)tests of 14 sets of cube specimens of the MCAC after 28 d of aging were conducted.The impact of the content and length of sisal fiber on the relationship between the fcu-RH and the fcu-UPV was determined.A mathematical model was established to predict the strength of the MCAC using the UPV,RH,and comprehensive UPV/RH methods and to obtain the curves of test strength.The applicability of the test strength curves of ordinary portland concrete(OPC),light-weight aggregate concrete(LAC),and coral aggregate concrete(CAC)to MCAC was assessed.The results showed that the test strength curves of OPC,LAC and CAC were inappropriate to determine the strength of MCAC using non-destructive method.The relative standard error of the curves of test strength of the RH method and the comprehensive method met the specifications,whereas that of the UPV method did not.展开更多
为了研究碱式硫酸镁水泥钢筋混凝土梁的静力和疲劳性能,分别制备了C30、C40和C50三种强度等级的碱式硫酸镁水泥(BMSC)和普通硅酸盐水泥(PO·C)钢筋混凝土梁试件。试验结果表明,钢筋混凝土梁试件跨中挠度随着静力荷载的增加而增加。C...为了研究碱式硫酸镁水泥钢筋混凝土梁的静力和疲劳性能,分别制备了C30、C40和C50三种强度等级的碱式硫酸镁水泥(BMSC)和普通硅酸盐水泥(PO·C)钢筋混凝土梁试件。试验结果表明,钢筋混凝土梁试件跨中挠度随着静力荷载的增加而增加。C40_((BMSC))和C50_((BMSC))的极限承载力分别为33 k N和38 k N,相比C40_((PO·C))、C50_((PO·C))的19 k N和21 k N分别提高了73.7%和81%。说明,高强度等级的BMSC试件具有较高的承载能力。在疲劳荷载的作用下,试件挠度值随着疲劳次数的增加呈下降趋势。高强度等级的BMSC试件疲劳循环寿命要多于PO·C试件,且强度等级越高,越为明显。此外,BMSC试件跨中挠度小于PO·C试件。说明,BMSC试件的刚度较大,抵抗变形的能力好。BMSC试件裂缝宽度发展包括三个阶段:快速发展阶段、稳定阶段和破坏阶段。碱式硫酸镁水泥完全能够用于制作钢筋混凝土构件,且性能更加优异,本文为碱式硫酸镁水泥混凝土能够大规模应用于结构工程提供了重要理论依据。展开更多
基金Funded by National Natural Science Foundation of China(Nos.51878350,11832013,52078250)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX21_0236)。
文摘Basic magnesium sulfate cement coral aggregate concrete(MCAC)is a new type of concrete consisting of basic magnesium sulfate cement,coarse coral aggregate,coral reef sand and seawater.The rebound hammer(RH),the ultrasonic pulse velocity(UPV)and the compressive strength(fcu)tests of 14 sets of cube specimens of the MCAC after 28 d of aging were conducted.The impact of the content and length of sisal fiber on the relationship between the fcu-RH and the fcu-UPV was determined.A mathematical model was established to predict the strength of the MCAC using the UPV,RH,and comprehensive UPV/RH methods and to obtain the curves of test strength.The applicability of the test strength curves of ordinary portland concrete(OPC),light-weight aggregate concrete(LAC),and coral aggregate concrete(CAC)to MCAC was assessed.The results showed that the test strength curves of OPC,LAC and CAC were inappropriate to determine the strength of MCAC using non-destructive method.The relative standard error of the curves of test strength of the RH method and the comprehensive method met the specifications,whereas that of the UPV method did not.
文摘为了研究碱式硫酸镁水泥钢筋混凝土梁的静力和疲劳性能,分别制备了C30、C40和C50三种强度等级的碱式硫酸镁水泥(BMSC)和普通硅酸盐水泥(PO·C)钢筋混凝土梁试件。试验结果表明,钢筋混凝土梁试件跨中挠度随着静力荷载的增加而增加。C40_((BMSC))和C50_((BMSC))的极限承载力分别为33 k N和38 k N,相比C40_((PO·C))、C50_((PO·C))的19 k N和21 k N分别提高了73.7%和81%。说明,高强度等级的BMSC试件具有较高的承载能力。在疲劳荷载的作用下,试件挠度值随着疲劳次数的增加呈下降趋势。高强度等级的BMSC试件疲劳循环寿命要多于PO·C试件,且强度等级越高,越为明显。此外,BMSC试件跨中挠度小于PO·C试件。说明,BMSC试件的刚度较大,抵抗变形的能力好。BMSC试件裂缝宽度发展包括三个阶段:快速发展阶段、稳定阶段和破坏阶段。碱式硫酸镁水泥完全能够用于制作钢筋混凝土构件,且性能更加优异,本文为碱式硫酸镁水泥混凝土能够大规模应用于结构工程提供了重要理论依据。
