不同化学溶液和冻融循环作用下砂浆力学特征的研究

通过对不同化学溶液和冻融循环共同作用下砂浆物理力学特性进行室内试验,研究了溶液的酸碱性、浓度和化学成分对砂浆化学冻融损伤劣化程度的影响,进一步分析了化学冻融后试样物理力学特性的变化规律,并对不同化学溶液下砂浆的冻融损伤劣化机理进行了探讨。试验结果表明:溶液酸性越强,砂浆物理力学参数的冻融损伤劣化程度越大;冻融初期,碱性NaOH溶液抑制了砂浆的损伤劣化的程度,但随着冻融循环次数的增加,这种抑制作用逐渐消失。相同条件下,Na2SO4溶液加剧了砂浆的冻融损伤程度。试样抗折强度的化学冻融损伤劣化程度相对于其抗压强度要严重得多;同时,基于化学冻融前后砂浆的孔隙率建立损伤变量.来定量地描述砂浆化学冻融损伤的劣化程度。

Experimental investigation on mechanical characteristics of mortar subjected to combined action of different chemical solutions and freezing-thawing cycles

Physical and mechanical characteristics of mortar subjected to the combined action of different chemical solutions and freezing-thawing cycles (F-T cycles) were experimentally studied. The effect of acidity and alkaline, concentration and chemical composition of solution on the deterioration degree of chemical freezing-thawing damage of mortar were studied. The variation pattern of physical and mechanical characteristics of samples after chemical freezing and thawing was further analyzed, and the damage deterioration mechanism of mortar in different chemical solutions was discussed. Experimental results show the stronger the solution acidity is, the greater the deterioration degree of freezing-thawing damage of mortar physical and mechanical parameters. At the beginning of experiment, alkaline NaOH solutions inhibits the freezing and thawing damage of mortar to some extent, but with the increase of freezing-thawing cycles, the inhibition gradually disappeared. Under the same conditions, Na2SO4 solution increased the damage degree of mortar specimens. Deterioration degree of flexural strength is much more severe than that of the compressive strength under the same conditions. The damage variable based on the porosity of mortar specimens before and after chemical and freeze-thawing is established to quantitatively describe the degradation degree of mortar specimens.