Preparation And Properties Of Alkali-excited Rock Wool Slag-based Non-autoclaved Aerated Concrete

Rock wool slag is the waste produced during the production of rock wool,consisting of unfibrillated melt（60%-70%）and rock wool fiber particles（30%-40%）.As the current production process of rock wool in China is based on cupola,the slag cannot be re-melted and used,and it is usually disposed of as landfill,which will cause serious environmental pollution,so the use of rock wool slag instead of cement production of building materials,not only to achieve solid waste reuse and further energy saving and emission reduction and environmental protection.In this paper,the feasibility of using rock wool slag as a precursor to prepare alkali-excited cementitious materials and preparing alkali-excited rock wool slag-based Preparation and properties of alkali-excited rock wool slag-based non-autoclaved aerated concrete aerated concrete is studied in a more systematic way by using hydrothermal analysis,image processing and three-dimensional reconstruction to provide theoretical guidance and technical support for the recycling of rock wool slag in the field of construction materials.The main research results are as follows:（1）When the water glass modulus is 1.4 and the alkali content is 5%,the 28 d compressive strength of rock wool slag-based alkali-excited cementitious material is the highest,and its value is 96.36 MPa.The setting time of alkali-excited rock wool slag slurry increases with the increase of water glass modulus and then decreases,while the setting time of slurry gradually shortens with the increase of alkali content.The increase of both modulus and alkali content will cause the decrease of flow degree of the slurry.（2）With the increase of Ti O₂ nano-doping,the setting time of alkali-excited rock wool slurry gradually shortens and the flow degree gradually decreases;the optimum doping of rutile and anatase Ti O₂ nano-doping is 0.75%,and the 28 d compressive strength of the samples is increased by 12.8%under this doping;compared with anatase Ti O₂ nano-doping,the effect of rutile Ti O₂ nano-doping on the performance of the samples is more significantly.（3）The optimum water-cement ratio of Preparation and properties of alkali-excited rock wool slag-based non-autoclaved aerated concrete aerated concrete using rock wool slag is 0.35,and the optimum mass ratio of foam stabilizer to aluminum powder is 1.4.Aerated concrete with dry density grades B04-B06 can be prepared with aluminum powder dosing of 0.150%-0.250%,and their strengths meet the requirements of strength grades A2.0-A3.5,respectively.The admixture of aluminum powder and foam stabilizer does not affect the physical phase composition of autoclaved free aerated concrete,and with the increase of aluminum powder admixture,the level-by-level porosity and the number of connected pores of the samples gradually increase and the number of pores decreases.