沙漠砂蒸压砖耐久性能的试验研究

Experimental study on the durability of steam compression brick in desert sand

利用沙漠砂研发的蒸压砖是一种新型建筑墙体材料,为研究这种墙体材料在新疆高烈度寒区的使用性能,依据《蒸压灰砂实心砖和实心砌块》标准对MU15的沙漠砂蒸压砖的软化系数、抗冻性能及碳化性能进行试验研究,并利用SEM及压汞技术对沙漠砂蒸压砖在各试验中强度变化的机理进行分析。结果表明:沙漠砂蒸压砖具有较好的抗冻性能和抗碳化的能力,冻融循环30次后的强度损失率仅为7.0%,完全碳化后的碳化系数为1.17,但软化系数一般,沙漠砂蒸压砖的软化系数仅为0.74;沙漠砂蒸压砖在冻融循环前期由于水化反应仍在进行,强度有所增加,随着冻融循环的不断增加,内部出现空洞,强度开始下降;沙漠砂蒸压砖碳化后的产物为颗粒状的CaCO3晶体,CaCO3晶体覆盖在砖体的表面,改善了孔径,提升了力学性能。

The autoclaved brick developed by using desert sand is a new type of building wall material in order to study the performance of this wall material in the high-intensity cold region of Xinjiang.The softening coefficient,frost resistance and carbonization properties of desert sand autoclaved bricks of MU15 are studied experimentally based on the standard of autoclaved sand-lime solid bricks and solid blocks,and the mechanism of strength change of desert sand autoclaved bricks in each test is analyzed by SEM and mercury compression techniques.The results are as follows:Desert sand autoclaved bricks have good resistance to freezing and carbonization,the strength loss rate after 30 freeze-thaw cycles is only 7.0%,and the carbonization coefficient after complete carbonization is 1.17.However,the softening coefficient is average,and the softening coefficient of desert sand autoclaved bricks is only 0.74;Desert sand autoclaved bricks increase in strength in the early stage of freeze-thaw cycles because the hydration reaction is still going on,and as the freeze-thaw cycles continue to increase,internal voids appear and the strength begins to decrease;The products of carbonization of desert sand autoclaved bricks are granular CaCO 3 crystals,and CaCO 3 crystals cover the surface of the bricks,improving the pore size and enhancing the mechanical properties.