Study on properties of Ultra-Lightweight Insulated Cementitious Composites for concurrent seismic and energy improving of existing RC frames

In the present paper, the properties of Ultra-Lightweight Insulated Cementitious Composites (ULICC) were investigated experimentally. Hollow Glass Microspheres (HGM) were used to improve thermal insulation capacity. The influence of water to blind ratio (W/B) and HGM volume content on the mechanical and thermal properties of ULICC mixtures was considered. The ULICC mixtures exhibited dry density of 1071–1358 kg/m3, tensile strength of 2.25–3.09 MPa, tensile strain capacity of 1.84–2.95%. Compressive strengths of ULICC were 35.2–57.1 MPa at 28 days by 100 mm cubic specimens. Noobvioussizeeffect on compressive strength was observed. The thermal conductivity coefficients ranged from 0.193 W/m.K to 0.227 W/m.K. Linear trend of compressive strength and thermal conductivity coefficient with HGM content were acquired. Three ULICC tensile curves considering compressive strength and tensile strain capacity were chosen for infills retrofitting analysis based on FEM. Skeleton curves, stiffness degradation, characteristic values, stress of ULICC plates were investigated by FEM results. FEM results indicated that infilled RC frame retrofitted by ULICC with higher compressive strength exhibited higher lateral carrying capacity. Strut effect of retrofitted infills acting at surrounding frame was enhanced due to ULICC mixture with highest strain capacity. Energy efficiency improvement was analyzed by heat transfer coefficients calculated. Energy saving requirements in Chinese codes can be met in hot summer and cold winter zone, as well as, cold zone after retrofit. Thermal insulation capacity of existing RC frames can be improved concurrently after retrofitted by ULICC.