半干硬混凝土外方内圆偏心约束收缩试验

采用外方内圆偏心约束试验方法对半干硬高掺量橡胶集料混凝土及未掺橡胶的半干硬普通混凝土进行约束收缩试验,并用静态电阻应变仪采集钢环内表面0°区、90°区、180°区在120 h内的环向应变值.试验结果表明:6组外方内圆偏心试件开裂截面均处在试件最窄处(0°区);半干硬橡胶混凝土早期收缩量及收缩率小于半干硬普通混凝土;半干硬橡胶混凝土试件开裂时间晚于半干硬普通混凝土,其前者裂缝宽度小于后者;所测应变值也首次验证了:0°区>90°区>180°区这一规律.计算0°区/90°区和0°区/180°区应变相对值,发现这两个值随时间变化趋于稳定.这表明,用静态线弹性有限元模拟外方内圆偏心约束收缩试验有其合理性.

Outside-square Inside-circle Eccentric Confined Shrinkage Test of Semidry Hard Concrete

The confined shrinkage test of crumb rubber concrete with high content and ordinary concrete without rubber which are semidry hard were done with outside-square inside-circle eccentric constraint method.And the circumferential strain of 0° zone, 90° zone and 180° zone on the inner surface of steel ring within 120 h was collected by static resistance strain gauge.The research results indicate that every splitting section on 6 sets of outside-square inside-circle specimens come into being at its narrowest part(0°zone).The early shrinkage and contraction percentage of semidry hard crumb rubber concrete was less than that of rubber-free semidry hard ordinary concrete.The cracking time of semidry hard crumb rubber concrete specimen was later than that of semi-dry hard ordinary concrete.The crack width of the former is smaller than the latter.And the measured strain values verify a certain rule for the first time: 0° zone>90° zone>180° zone.The relative values of strain at 0° zone/90° zone and 0° zone/180° zone were calculated and it was found that these two values stabilized with time.This indicates that it is reasonable to use the static linear elastic finite element method to simulate the outside-square inside-circle eccentric confined shrinkage test.