中文摘要：

在自然营力和人为作用下,平遥古城墙和民居的青砖产生了严重的风化病害,亟须保护和修复。通过现场调查,发现风化病害发生部位都在毛细水上升高度范围内（距地面1-3m）,主要风化形式为等厚状剥落、鳞片状剥落、颗粒脱落、盐分结晶。通过室内测试和实验,得到了古砖的矿物、化学成分,物理、力学性质以及耐盐、耐冻性能。本文认为毛细水在墙体中上升时携带的盐分是古砖风化的主要原因,冻融循环则加剧了风化的进程。由于水分减少和/或温度降低,古砖孔隙中的可溶盐会＂捕获＂自由水使其变成带有若干结晶水的结晶盐。盐分结晶后体积增大在古砖孔隙中产生的膨胀力致使古砖破坏。根据古砖的风化机理,提出了＂阻水、脱盐、强砖＂的防风化方法。本文提出的古砖风化机理和防风化方法的技术流程和分析方法,可以为相关砖石文物的保护和修复提供参考。

英文摘要：

Due to natural and anthropogenic forcing,the ancient blue bricks in walls and dwellings of Pingyao ancient city have suffered a serious weathering diseases. They are in badly need of protection and restoration. This field investigation finds that all weathering diseases occur in the range of rising height of capillary water（ 1 - 3m higher than the ground surface）. Main weathering types of the blue bricks include contour scaling,flaking,powdering,salt crystallization. Laboratory tests determines the mineral composition,major elements,physical properties,mechanical strength,as well as performance of resistance to salt crystallization and frost. The weathering reason of the ancient brick is the salts carried by capillary water when rises. The process is aggravated by frost also due to rising of the capillary water. Salts are derived from the soluble salts carried by capillary water when rises.Due to evaporation of capillary water and/or decrease in temperature,the soluble salts in the pores of the ancient bricks become crystal salt,in the meantime the capillary water is captured and transformed to crystal water. The process can generate powerful expansive pressure in the brick pores,leading to brick failure. Methods to prevent further weathering diseases are demonstrated. They are capillary water-proofing, salt-eliminating and brickstrengthening. Technical process and analysis method,presented by the paper on weathering mechanism andweathering prevention for the ancient brick,can provide references for protection and restoration of related buildings of cultural heritage.