Experimental study on humidity control performance of diatomite-based building materials

The humidity control performance of three types of diatomite-based building materials are experimentally studied. The distributions of the pores and matrix of the diatomite-based humidity control building materials (DBHCBMs) are visually characterized by micrographs and statistical analysis methods. The surface contact angle of the DBHCBMs is measured using an optical contact angle measuring device to evaluate the surface free energy. The saturated solution method is applied to measure the humidity control performance of the DBHCBMs. The effects of pores parameters (porosity, pore size distribution, surface contact angle), ambient temperature and relative humidity (RH) on the humidity control performance of the DBHCBMs are studied. The experimental results indicate that the humidity control performance of DBHCBMs is strongly affected by the pore parameters and surface contact angle. The DBHCBMs with tiny pore diameter, large amount of tiny pores and large surface contact angle have higher adsorption ability. The ambient temperature and the RH also have considerable influence on the adsorption performance of DBHCBMs.