塑性混凝土弹性模量室内试验研究

Testing on elastic modulus of plastic concrete

通过4种变形标距的弹性模量试验,研究了塑性混凝土弹性模量的合适测试方法。塑性混凝土棱柱体试件设置300mm、200mm、150mm和100mm共4种测试标距,其中300mm标距下的力和位移数据采用计算机自动采集,其余标距采用人工读数。结果表明,利用自动采集数据模式测得塑性混凝土弹性模量值最稳定,且其值远远小于人工读数模式下的值;一般而言,测试标距小,弹性模量值大,全长标距下弹性模量值最小;利用自动采集数据模式下得到单轴压缩应力应变曲线具有典型初始压缩弯曲段、较长的下降段,而人工读数下几乎不能测出初始压缩弯曲段,而主要表现为较长直线上升段。分析了塑性混凝土利用普通混凝土弹性模量计算公式的不足,提出利用其单轴峰值强度的0.3倍、0.7倍对应的点计算其弹性模量。同时提出室内测试塑性混凝土弹性模量试验时不需预压。

Elastic modulus of plastic concrete is studied by testing with 4 standard distance of 300mm, 200mm, 150mm and 100mm. The result shows that the method which is measured by computer is best, and the elastic modulus is most steady, and it is much less than that by manual record. The stress -train curve by computer record has beginning compressive bend period and longer descending period, but that by manual record has no beginning compressive bend period and has longer ascending linear period. It is presented that elastic modulus of plastic concrete can be calculated using with the two points of 0.3 and 0.7 of the maximum uniaxial compressive strength, and prepressing is not necessary before testing.