已硬化砼中未水化水泥安定性的检测及事故处理

Detection of soundness of unhydrated cement in hardened concrete and its treatment

在已硬化砼中水泥安定性不合格的主要原因是水泥熟料矿物中含有过多游离氧化钙或游离氧化镁 .在砼结构中主要表现为局部酥松变形、砼开裂、构件崩溃等 .在工程中实用的过烧游离氧化钙的检测方法有沸煮法、X射线衍射法和甘油精法 .一旦发现施工现场水泥安定性不良 ,应按情况组织检查、退货、确定事故原因及影响范围 ,或打掉重浇 。

The main cause leading to the disqualification of cement soundness in hardened concrete is excessive f-CaO or magnesia in the cement mixture. Its effect on concrete structure results in partial incompact, cracking and sudden failure of the structure. Methods of detection of over-burned calcium oxide used in practical work are boiling, X-ray diffraction (XRD) and glycerin. Once the disqualification of the cement used in construction is certified, measures to be taken are suggested in this paper as the following: inspection, returning of the cement, investigation of causes of accident and its influential context, knocking off the affected structure and its recasting,strengthening the monitoring and management of the construction.