Experimental investigation of the thermal and mechanical properties of lightweight aggregate concrete mixed with microencapsulated phase change materials
Lin Zhu, Faning Dang, Yi Xue, Weihua Ding, Kai Jiao
Abstract
An optimal mix proportion design program was developed firstly in this research by analyzing most relevant factors affecting the mix ratio, such as water-cement ratio, workability, drying mass, adding and mixing method of MPCM, etc. Then, the influences of MPCM on density, porosity, compressive strength, thermal conductivity, specific heat capacity, and thermal diffusivity of LWAC were investigated by changing curing time, MPCM content, and MPCM state. Results shown that the porosity of MPCM-LWAC linearly increases and corresponding density linearly decreases with the increase of MPCM content. SEM images of MPCM-LWAC reveal weaker connection and higher porosity between aggregate and mortar caused by more MPCM. The addition of MPCM to LWAC causes a compressive strength loss proportional to the MPCM content. The compressive strength of MPCM-LWAC increases with the increasing curing time; however, growth rate of compressive strength decreases with the increasing MPCM content. When the MPCM content reaches a maximum of 10%, the compressive strength of MPCM-LWAC at 50°C is 4.7% less than that of MPCM-LWAC at 20°C. For the 10% MPCM addition, the specific heat capacity increased by 32.09%, and the thermal conductivity and thermal diffusion reduced by 19.0% and 23.9%, respectively.