High Temeprature Resistance Of Cementitious With Nano-materials

Properties of cementitious with nano-materials are different from normal mortar. This paper focused on high temperature resistance of cementitious with nano-materials and found HPNCC is a better fire resistance material. If HPNCC can be used in fire proof structure and repair of structures subjected to fire, it will be an energy saving, as an environmentally friendly, economical building material.1、Results of mechanical tests showed that compressive strength and flexural strength of mortar with nano materials varied with elevated temperatures. Part of the mortar with only nano materials addition showed slightly lower strength loss percentage, while the residual strength is low, and HPNCC showed good high temperature resistance.2^Surface color of HPNCC changed when exposed to elevated temperatures, while number and size of crack and pore increased, and no burst and fragmentary phenomenon were observed. The specimens at room temperature and after high temperature exposure were taken to SEM scans. It was found that as temperature rising, dehydration of cement and fly ash hydration products became worse, and crystal was damaged. When exposed to200℃,PVA fibers started to melt and volatilize, and when exposed to400℃,most of the PVA fibers disappeared, and PVA fibers eventually totally vanished at600℃.XRD, TGA and mercury analyzer were used to analyze the change of microstructure and chemical composition of HPNCC. Deterioration of the microstructure occurred during heating, and physical properties (such as evaporation, pore structure deterioration, mass loss, etc.) and chemical composition also changed. Changes of microstructure and macroscopic mechanical properties are closely related.3、High temperature resistance of HPNCC wrapped concrete columns was examined in this paper, and HPNCC showed great high temperature performance, which was beneficial to high temperature resistance of composite members.