掺造纸白泥蒸压加气混凝土的力学性能及水化产物的研究

Mechanical Properties and Hydration Products of Autoclaved Aerated Concrete Mixed with Papermaking White Mud

为利用造纸行业产生的废弃物,本文在普通砂基蒸压加气混凝土的基础上,采用造纸白泥替代砂,研究造纸白泥掺入质量分数和硅质材料组成对掺白泥蒸压加气混凝土强度和干密度的影响规律,并通过X射线衍射分析、傅里叶红外光谱法、热重-差式扫描量热法对其水化产物进行分析。研究结果表明:造纸白泥掺入质量分数对蒸压加气混凝土的强度影响较大,随着造纸白泥掺量的增加,蒸压加气混凝土的强度从5.33 MPa降低至1.20 MPa;用硅灰替代部分砂能够有效提高制品强度;蒸压养护后,硅灰和砂与氧化钙反应生成了托贝莫来石、硬硅钙石和低碱度C-S-H;当造纸白泥质量分数为40%,硅灰质量分数为10%,制品抗压强度为3.87 MPa,干密度为607 kg/m^(3),能够达到A3.5强度等级和B06干密度等级。

To utilize the waste produced by papermaking industry,on the basis of ordinary sand-based autoclaved aerated concrete,papermaking white mud was used to replace sand.The effects of mass fraction of papermaking white mud and silica material composition on the strength and dry density of autoclaved aerated concrete with white mud were studied.The hydration products were analyzed by X-ray diffraction,Fourier transform infrared spectroscopy and thermogravimetric-differential scanning calorimetry.The results show that the mass fraction of papermaking white mud has a great influence on the strength of autoclaved aerated concrete.With the increase of papermaking white mud addition amount,the strength of autoclaved aerated concrete decreases from 5.33 MPa to 1.20 MPa.Partial replacement of sand with silica fume can effectively improve the strength of products.After autoclave curing,the tobermorite,xonotlite and low alkalinity C-S-H are formed from silica fume and sand reacting with calcium oxide.The compressive strength is 3.87 MPa,and the dry density is 607 kg/m^(3) when the mass fraction of papermaking white mud is 40%and the mass fraction of silica fume is 10%,whose strength grade and dry density grade reach A3.5 and B06,respectively.