桩基工程3D打印混凝土材料工程性质研究

通过开展桩基工程3D打印混凝土材料工程性质试验研究,提出采用42.5R快硬硫铝酸盐水泥、小粒径的建筑干砂和石子为主要材料,通过坍落度试验和抗压试验,得出水灰比越大,材料的坍落度越大;砂率越大,材料的坍落度先降低后增大,最终确定当水灰比为0.39和砂率为0.536时,流动性相对较好;同时通过添加葡萄糖酸钠缓凝剂来控制材料的凝结时间,当占比0.71%时,材料能够保持较长时间塑性,有利于较好控制拌和后混凝土的凝结时间;通过添加聚羧酸减水剂来增大材料的流动性和抗压强度,当添加比为0.48%时效果最佳。通过一系列的室内试验,制备出一种适用于桩基工程3D打印的新型混凝土材料。

Study on engineering properties of 3D printing concrete materials for pile foundation engineering

The experimental study of the engineering properties for 3D printing concrete materials used in pile foundation engineering is carried out. 42.5R rapid hardening sulphoaluminate cement,smalldiameter construction dry sand and gravel are used as the main materials. Through the slump test and compressive strength test,it shows that the larger the water-cement ratio is,the larger the slump of material is;when the sand rate is larger,the slump of the material decreases firstly and then increases. Finally,when the water-cement ratio is 0.39 and the sand rate is 0.536,the fluidity is relatively good;at the same time,the setting time of the material is controlled by adding sodium gluconate retarder. When the proportion is 0.71%,the material can maintain a longer time plasticity,which is beneficial to the better control of the setting time of the concrete after mixing. By adding polycarboxylate superplasticizer,it can increase the fluidity and compressive strength of the material,the addition ratio0.48% is the best. Through a series of laboratory tests,a new type of concrete material suitable for 3D printing of pile foundation engineering is given.