羟丙基甲基纤维素对3D打印砂浆性能的影响

By studying the influence laws of different dosages of hydroxypropyl methyl cellulose (HPMC) on the printable performance, rheological properties and mechanical properties of 3D printing mortar, the appropriate dosage of HPMC was discussed, and its influence mechanism was analyzed in combination with the microscopic morphology. The results show that the fluidity of the mortar decreases with the increase of the HPMC dosage, that is, the extrudability decreases with the increase of the HPMC dosage, but the fluidity retention ability is improved, and the mortar still has good extrudability after adding an appropriate dosage of HPMC; the shape retention rate under self-weight and the penetration resistance both increase significantly with the increase of the HPMC dosage, that is, with the increase of the HPMC dosage, the stackability is improved and the printable time is extended; from the perspective of rheology, with the increase of the HPMC dosage, the apparent viscosity, yield stress and plastic viscosity of the slurry increase significantly, and the stackability is improved; the thixotropy first increases and then decreases with the increase of the HPMC dosage, and the printable performance is improved; an excessive HPMC dosage will cause an increase in the porosity of the mortar and a decrease in strength, and it is recommended that the HPMC dosage not exceed 0.20%.

通过研究不同掺量羟丙基甲基纤维素(HPMC)对3D打印砂浆可打印性能、流变性能及力学性能的影响规律,探讨了HPMC的适宜掺量,并结合微观形貌分析其影响机理.结果表明:砂浆流动度随着HPMC掺量增加而降低,即可挤出性随着HPMC掺量增加而降低,但流动性保持能力提高,加入适宜掺量的HPMC后砂浆仍具有良好的可挤出性;自重下形状保留率、贯入阻力均随HPMC掺量增加而显著增加,即随HPMC掺量增加,可堆叠性提高,可打印时间延长;从流变学的角度来看,随着HPMC掺量的增加,浆体表观黏度、屈服应力和塑性黏度显著增大,可堆叠性提升;触变性随HPMC掺量增加而先增大后减小,可打印性能提升;HPMC掺量过高会引起砂浆孔隙率增大、强度下降,建议HPMC掺量不超过0.20%.