Experimental investigation and analysis on flexural performance of functionally graded composite beam crack-controlled by ultrahigh toughness cementitious composites  

作　　者：LI QingHua XU ShiLang 

机构地区：[1]State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China

出　　处：《Science China(Technological Sciences)》2009年第6期1648-1664,共17页中国科学（技术科学英文版）

基　　金：Supported by the Key Program of the National Natural Science Foundation of China(Grant No.50438010);the Research and Application Programs of Key Technolo-gies for Major Constructions in the South-North Water Transfer roject Construction in China(Grant No.JGZXJJ2006-13)

摘　　要：Based on the concept of functionally graded concrete,UHTCC(ultrahigh toughness cementitious composites)material with excellent crack-controlling ability is strategically substituted for part of the concrete,which surrounds the main longitudinal reinforcement in a reinforced concrete member.Investigations on bending behavior of such a functionally graded composite beam crack-controlled by UHTCC(abbreviated as UHTCC-FGC beam)have been carried out.After establishing a theoretical cal-culation model,the paper discusses the results of four-point bending experiment on long composite beams without web reinforcement,and validates the theoretical formulae through experimental results of UHTCC-FGC beams with different thicknesses of UHTCC layer.Besides improving bearing capacity and saving steel reinforcements,the results indicate that UHTCC-FGC beams can also effectively control the deformation and enhance the ductility of members.At last,the optimal thickness of UHTCC layer in UHTCC-FGC beams has been confirmed,which can not only save materials and improve mechanical performance of members,but also be very effective in preventing corrosion-induced damage and enhancing the durability of members by controlling crack width below 0.05mm under service conditions.Based on the concept of functionally graded concrete, UHTCC (ultrahigh toughness cementitious composites) material with excellent crack-controlling ability is strategically substituted for part of the concrete, which surrounds the main longitudinal reinforcement in a reinforced concrete member. Investigations on bending behavior of such a functionally graded composite beam crack-controlled by UHTCC (abbreviated as UHTCC-FGC beam) have been carried out. After establishing a theoretical calculation model, the paper discusses the results of four-point bending experiment on long composite beams without web reinforcement, and validates the theoretical formulae through experimental results of UHTCC-FGC beams with different thicknesses of UHTCC layer. Besides improving bearing capacity and saving steel reinforcements, the results indicate that UHTCC-FGC beams can also effectively control the deformation and enhance the ductility of members. At last, the optimal thickness of UHTCC layer in UHTCC-FGC beams has been confirmed, which can not only save materials and improve mechanical performance of members, but also be very effective in preventing corrosion-induced damage and enhancing the durability of members by controlling crack width below 0.05 mm under service conditions.

关 键 词：UHTCC CRACK control functionally GRADED EXPERIMENTAL research validation DURABILITY 

分 类 号：TB332[一般工业技术—材料科学与工程]