酸雨—碳化耦合侵蚀对混凝土回弹测强准确度的影响

Effect of Acid Rain-Carbon Coupling Erosion on the Accuracy of Rebound Strength Measurement of Concrete

基于回弹法检测混凝土强度在现场实体结构中的广泛应用,以及我国大气污染带来的酸雨问题,采用加速碳化和模拟酸雨侵蚀进行试验,从两种因素单独作用和共同作用的角度,研究混凝土的中性化深度值、表面硬度、抗压强度及其与回弹强度推定值之间的关系。结果表明:碳化对混凝土的中性化、表面硬度和抗压强度有较大的影响;酸雨中的硫酸根离子对混凝土中性化有一定的抑制作用,但对其表面硬度和初期抗压强度有一定的提升作用;经酸雨-碳化耦合侵蚀后的混凝土表层微观结构显著异常,此时直接采用国家统一测强曲线推算现场实体结构则混凝土的强度与试件抗压强度之间存在较大的偏差,回弹测强准确度较低,需要引起关注。

Based on the extensive application of the rebound method in the detection of concrete strength in the field solid structure and the acid rain problem caused by air pollution in China,accelerated carbonization and simulated acid rain erosion tests are adopted from the point of view of the two factors acting separately and jointly to study the relationship between the values of neutralization depth,surface hardness,compressive strength and springback strength.The results show that carbonation has a great contribution to the neutralization of concrete,surface hardness and compressive strength,and sulfate ion in acid rain can inhibit the neutralization of concrete to some extent and have a certain contribution to the surface hardness and initial compressive strength.After carbonization and acid rain coupling erosion, the micro-structure of concrete surface is obviously abnormal.At this time,the strength of concrete with solid structure is calculated directly by using the national unified strength curve,and there is a big deviation between the strength of concrete and the compressive strength of the specimen.The accuracy of rebound measurement is low,which needs to be paid attention.