混凝土粗糙面几何特征采集的压饼拓模法试验研究

Experimental study on geometric feature acquisition of concrete rough surface by pressing cake⁃rubbing method

提出适用于粗糙面几何特征采集的压饼拓模法,并介绍了压饼仪构造及使用方法,使用此方法进行了5种不同预置时长的超轻黏土物理性能和拓印精度试验。结果表明:当黏土开封预置2h左右时,可获得最优拓模精度;塑性沉陷值比含水率更适宜作为界面粗糙度拓模精度控制的黏土物理性质评价指标,当黏土塑性沉陷值不小于1.5mm时,对应点平均误差在0.3mm以内;回弹值对拓模精度影响不大。同时采取增大按压压力、二次按揉、附加刚性背板等措施进行拓模精度影响研究。结果表明:按压压力不应小于50N;二次按揉可提高模印精度;采用刚开封黏土时,附加刚性背板措施可实现高精度即时脱模,其对应点平均误差在0.12mm以内。

A pressing cake⁃rubbing method was proposed for geometric feature of rough surface,and the construction and application of press rubbing device were introduced.With this method,the physical properties and rubbing accuracy of 5 kinds of ultra⁃light clay with different preset times were tested.The results show that optional rubbing accuracy can be obtained when the clay is opened and preset for about 2h.The plastic settlement value is more suitable than the moisture content to evaluate the clay physical properties for the interface roughness rubbing accuracy control.When the plastic settlement value is not less than 1.5 mm,the average error of the corresponding point is less than 0.3 mm.The rebound deformation value has little effect on rubbing accuracy.At the same time,measures such as increasing pressing pressure,second press and knead and attaching rigid backboard were taken to study the influence of rubbing accuracy.The results show that the pressing pressure should not be less than 50N,second press and knead can improve rubbing accuracy.When using freshly opened clay,high accuracy immediate demoulding can be realized by using rigid backboard,and the average error of corresponding points is less than 0.12mm.