基于Bingham模型的新拌自密实混凝土流变参数反演研究

Back Analysis of Self-compacting Concrete Rheological Parameters Based on Bingham Model

目前测定新拌自密实混凝土流变参数的方法均存在各自的缺点,为了方便准确地测定流变参数,提出了新拌自密实混凝土流变参数正法反演的理论和方法:假定其流变模型为宾汉姆模型,将改进L-箱试验作为已知输入,新拌自密实混凝土在不同时间点的流动形态作为已知的输出,利用计算流体力学方法计算流动形态,加权最小二乘法建立目标函数,结合改进L-箱试验数据,采用坐标轮换法进行反演,得到了符合新拌自密实混凝土流动性的流变参数。

The direct back analysis theory and method of fresh self-compacting concrete rheological parameters are proposed to deter-mine the rheological parameters ,this method is much easier and more accurate than current test methods which have their draw-backs .The rheological model of fresh self-compacting concrete is assumed to be Bingham model ,with the modified L -box test as known input and the flow patterns of fresh self-compacting concrete at different time as known output ,flow patterns of fresh self-compacting concrete are simulation by the computational fluid dynamics method ,the objective function is established with the weigh-ted least square method ,the rheological parameters of fresh self-compacting concrete are obtained by a back analysis case with the co-ordinate alternation method based on experimental data of modified L -box test ,analytic results show that the rheological parameters accord well with the real flow behavior of fresh self-compacting concrete .