风积沙3D打印砂浆材料参数与各向异性研究

Material Parameters and Anisotropy Research of 3D Printing Mortar After Incorporating with Aeolian Sand

通过前期的大量研究,得到两组风积沙3D打印砂浆配合比,对其材料参数进行了3D打印测试,并对打印试件进行了各向异性研究。结果表明:与基准配合比的试件相比,两组风积沙3D打印砂浆的打印性能较优,28 d抗折强度略低于基准组,抗压强度略高于基准组。当打印工艺参数相同时,试件的各向异性存在一致的规律,材料配比不同,各向异性离散程度也不同,且随着龄期的不同发生改变。通过SEM观察纤维界面、骨料界面的黏结状态,发现聚丙烯纤维表面较为光滑,与水泥石的黏结较差;风积沙表面附着更多的水化产物,与水泥石的黏结较好。

On the basis of a lager number of the previous research,the mix proportions of two groups of aeolian sand 3D printing mortar were obtained,the material parameters were tested by 3D printing test,and the anisotropy of printed specimens was studied in this study.The results indicated that the 3D printing mortar of the two groups of aeolian sand showed better printing performance,the flexural strength of mortar after curing for 28 d was slightly lower than that of the reference group 3D printing mortar,the compressive strength of mortar was sligthtly higher than that of the reference group 3D printing mortar.Meanwhile,when the printing process parameters of the materials were the same,the anisotropy of spe-cimens existed same law;when the material proportion was different,the dispersion degree of anisotropy was different and changed with different curing ages.Moreover,the bond state of fiber interface and aggregate interface was investigated by the scanning electron microscope(SEM)test,and the result showed that the surface of polypropylene fiber was smooth and the bond with cement stone was poor;the surface of aeolian sand attached to more hydration products,and it showed good bonding with cement stones.