返碱是水泥制品时常发生的状况。造成这一现象的原因很多，例如低温施工，空气潮湿，粘结剂水泥含碱量过高等等。所谓“返碱”，就是我们常看到的一些白色的结晶物从石材的表面析出。白返碱或表面起白霜是因为水泥水化产生的氢氧化钙，随着水分从内部迁移到表面，水分蒸发氢氧化钙结晶析出形成白斑。返碱可以通过专业溶剂（草酸：水=1:5）处理。操作时，应用刷子蘸取溶剂在返碱的表面刷洗，清理干净之后，用清水冲洗。

When efflorescence occurs, as it does with many masonry products, it is the usually the result of moisture migration through the masonry substrate. Once the moisture is on the masonry surface, it evaporates, depositing dissolved salts in the form of efflorescence. Efflorescence naturally disappears over time as long as the moisture source is controlled or eliminated. Efflorescence may be removed with a solution of 1 part white vinegar to 6 parts water. Scrub using a soft bristle brush and vinegar/water solution. Rinse well with clean water.