Research On The Perfoemance Of AAC Self-energy Conservation Wall And Special Mortar In Cold Regions

Autoclaved aerated concrete is the only single wall materials that can meet the 65% building energy saving, which is widely used as a filler wall building structure, because of light weight, heat preservation, excellent seismic performance and also a certain strength. When AAC blocks are combined with ordinary cement mortar, the thermal bridge, surface mortar cracking off and other issues would restrict its practical application.Therefore, to solve these problems, this paper study thermal insulation mortars that are suitale for AAC walls both in strength and thermal properties, and the temperature field and temperature stress of AAC walls are also analyzed.The vitrified bead is used as lightweight aggregate to confect the thermal insulation mortar special for AAC blocks. When the dosage of vitrified beads is 60% of the cement and fly ash replaces 25% of cement, the compressive strength of insulation mortar can reach 5.8 MPa, the coefficient of thermal conductivity can attain 0.13 W/(m·K), meeting the targets. On this basis, this paper explores the mechanical properties of AAC masonry with different mortar joint thickness. The experimental results show the compressive strength of masonry with 10 mm mortar joint is 3.72 MPa, the compressive strengt and shear strength of masonry with 6mm mortar joint reach 3.10 MPa and 0.222 MPa.Using vitrified beads, cement, fly ash, Ca(OH)2, polypropylene fiber and some other agents to confect thermal insulation surface mortar. When the mass proportion of cement, fly ash, Ca(OH)2, vitrified beads, fiber, re-dispersible polymer powder, HPMC, water reducing agent and air-entraining agent is 83: 10: 7: 100: 0.6: 1.5: 0.6: 0.3: 0.02, the compressive strength of the mortar can reach 2.6 MPa, 0.7 MPa of flexural strength, and 0.43 MPa of bonding strength, meantime, the flexural compression ratio is less than 3, and coefficient of vapour permeation is 0.88×10-4 g/(m·h·Pa).As temperature stress and temperature deformation occur in the AAC walls, ANSYS software is utilized for temperature field, temperature stress and temperature deformation simulation analysis. Calculation results show that the surface insulation mortar can effectively reduce the AAC block wall substrate temperature changes, 1.668℃ reduction in summer and 5.315℃ reduction in winter. For fixed wallboard, the stress is reduced by 49%; for free wallboard, the stress is reduced by 30%, at the same time, wall deformation is lower.