幕墙用干挂石材冻融循环及力学试验研究

RESEARCH ON FREEZE-THAW CYCLE AND MECHANICS TEST OF DRY HANGING STONE FOR CURTAIN WALL

开展冻融循环及力学试验对幕墙用天然干挂石材花岗岩、石灰石、砂岩进行了冻融影响研究,并结合文献对石材冻融损伤模式进行了探讨。结果表明,冻融循环作用会引起石材质量变化,不同石材变化走势不同,其对石材外观变化的影响不明显;冻融对吸水率较低的花岗岩强度的影响要远小于其对吸水率较高的石灰石、砂岩的影响,当吸水率大到一定程度以后,吸水率对冻融引起的强度变化则不敏感;相对于抗压性能,冻融循环对石材的抗弯性能影响更大;这三种石材的冻融损伤模式为:裂纹扩展模式和颗粒析出模式。

Freezing-thawing cycle and mechanical tests were carried out to study the impact of freezing-thawing on granite, limestone, and sandstonefor the curtain wall.The results show that the water absorption rate of the three kinds of stone materials is small and meets the requirements of the specification, and the effect of freeze-thaw cycle on the appearance change is not obvious.Furthermore, the influence of freeze-thaw on the strength of granite with low water absorption rate is much smaller than that of limestone and sandstone with high water absorption rate. In addition, when the water absorption rate reaches a certain extent, the water absorption rate is not sensitive to the strength change caused by freeze-thaw.With respect to the compressive performance, freeze-thaw cycle has a greater impact on the bending resistance of stone. Finally, the freeze-thaw damage modes of these three stones arecrack growth mode and particle precipitation mode.