3D打印风积沙混凝土抗碳化性能试验研究

Experimental study on carbonation resistance of3D printed concrete with aeolian sand

【目的】进一步明晰3D打印风积沙混凝土的抗碳化性能。【方法】制备3D打印风积沙混凝土试件(以下简称为3D打印试件),研究沙胶比对3D打印试件碳化深度的影响,并引入碳化各向异性系数来评估3D打印工艺对混凝土碳化行为的影响;测试分析碳化后3D打印试件的抗压、抗折性能,并基于沙胶比在x、y、z 3个方向建立3D打印风积沙混凝土碳化深度预测模型。【结果】3D打印试件的碳化深度随碳化龄期和沙胶比的增加而增加,并且碳化深度和碳化后的力学性能均表现出明显的各向异性;在碳化28 d后,与打印基体相比,3D打印试件的打印条间、打印层间的碳化深度分别增加了24%和10%。【结论】碳化作用在一定程度上减弱了3D打印试件抗压强度和抗折强度的各向异性。

[Purposes]The paper aims to further clarify the carbonation resistance of 3D printed aeolian sand concrete.[Methods]In this paper,3D printed desert sand concrete was prepared,and the influence of sand-binder ratio on the carbonation depth of 3D printed concrete was studied.The anisotropy coefficient of carbonation was introduced to evaluate the effect of 3D printing process on the carbonation behaviors of concrete.The compressive and flexural properties of 3D printed concrete after carbonization were tested and analyzed,and the carbonization prediction model of 3D printed concrete was established based on the sand-binder ratio in x,y and z directions.[Findings]The carbonization depth increased with the increase of carbonization age and sand-binder ratio,and the carbonization depth and mechanical properties showed obvious anisotropy.After 28 days of carbonization,compared with the printing matrix,the carbonization depth between printing strips and layers increased by 24%and 10%respectively.[Conclusions]Carbonation reduced the anisotropy of compressive strength and flexural strength of 3D printed specimens to a certain extent.