氯化钙和尿素对珊瑚砂胶结的影响

Influence of Calcium Chloride and Urea on Coral Sand Cementation

使用不同浓度氯化钙、尿素以及氯化钙尿素混合溶液浸泡珊瑚砂试样,干燥后得到具有一定强度的珊瑚砂柱,研究其表观、强度和微观结构特性,分析结晶种类和溶液浓度对珊瑚砂胶结的影响。结果表明:尿素结晶对砂土颗粒的胶结作用不明显,试样未能较好成型;氯化钙和氯化钙尿素混合结晶对砂土颗粒的胶结作用较明显,砂柱强度最高接近6 MPa。氯化钙胶结试样强度随溶液浓度增加先增大后减小,溶液浓度为3 mol/L左右时强度最大;混合溶液胶结试样强度随溶液浓度增加而不断增大。3种胶结试样微观图像的灰度熵、欧拉数和孔隙的定向度、分布分维随溶液浓度增加而减小;颗粒定向度和分布分维随溶液浓度增加而增大。氯化钙和氯化钙尿素混合溶液胶结试样颗粒面积比例、颗粒与孔隙圆形度均大于尿素胶结试样。

Different concentration of calcium chloride,urea and calcium chloride-urea mixture solutions were utilized to soak coral sand samples,which turns to tight columns with a certain of strength after drying.By studying the appearance,strength and microstructure features of these columns,the influence of crystallization type and solution concentration on coral sand cementation were analyzed.The test results shows that the coral sand cementation with urea crystallization is not obvious and the samples are not shaped well;the cementation with calcium chloride and calcium chloride-urea crystallization were obvious while the strength of the sand column could reach to 6 MPa.The strength of samples cemented with calcium chloride increases first,then decreases with the increase of solution concentration,and reaches maximum with the concentration of 3 mol/L;while the strength of samples cemented with calcium chloride-urea increases with the increase of solution concentration.The Gray entropy,Euler value,orientation and distribution fractal dimension of the pore decrease with the increase of solution concentration,while the orientation and distribution fractal dimension of the particle increase with the increase of solution concentration.Area proportion of particle,roundness of pore and particle of samples cemented with calcium chloride-urea are larger than those of samples cemented with urea.