碳化混凝土中不同深度处pH值变化规律研究

An investigation of the pH variation in carbonated concrete under different depth

采用浸取法和挤压法对碳化混凝土不同深度处pH值变化规律展开研究。考虑了水胶比、水泥用量和粉煤灰用量3个因素对碳化混凝土不同深度处pH值的影响。实验结果表明,碳化混凝土存在部分碳化区、完全碳化区和未碳化区。水胶比对碳化混凝土不同深度处pH值影响不大,而粉煤灰和水泥的用量对碳化混凝土不同深度处pH值有较大的影响;水泥用量对部分碳化区的长度影响较小,粉煤灰的使用对混凝土碳化有促进作用,但减小了部分碳化区的长度。采用挤压法得到的结论与浸取法的结果一致。但是挤压法所得到的孔溶液pH值更可靠,更具有说服力。因此采用挤压法对碳化混凝土不同深度处的pH值进行研究比较合理。

This paper adopted leaching and extrusion method to study the pH variation in different depth. Water-cement ratio,fly ash content,cement content were considered as three main factors affecting the pH of carbonated concrete at different depth and were researched in the test. The result showed that incomplete carbonation zone,complete carbonation zone and none carbonation zone were existed in the carbonated concrete. The influence of water-cement ratio on the pH in different depth was small,while the influence of fly ash content and cement content on that is great. The cement content had little effect on the length of incomplete carbonation zone,and fly ash could decrease the length of incomplete carbonation zone. The conclusion obtained by extrusion method is consistent with leaching method. However, the hole liquor pH obtained by extrusion method is more reliable and more persuasive. So that using extrusion method to study the pH variation in carbonated concrete is reasonable.