Cement aerogel building envelopes: achieving building energy efficiency and acoustic noise reduction

초록

To combat the global energy crisis and facilitate green building, this study explores a cement aerogel (PCASPm) with a "brick-mud" structure manufactured through directional-freezing technology. Owing to the hydration of calcium aluminum silicate (C-A-S-H) and chemical cross-linking of phytic acid (PA), PCASPm shows excellent mechanical properties at the component and structural levels with a compressive strength of 0.79 MPa at 10 % and 1.2 MPa at 20 % compression, and a negative Poisson's ratio. The chemical cross-linking of PA results in a uniform pore-size distribution in samples with a porosity of 73.0 %, resulting in a low radial shrinkage of 9.3 % and an apparent density of 164.7 kg/m3. Moreover, the "brick-mud" structure imparts excellent thermalinsulation (as low as 0.027 W/(m & sdot;K)) and noise-reduction properties (alpha max = 0.93, NRC = 0.50, 10 mm) to PCASPm. Fire scenario simulations show that PCASPm is highly flame retardant. Simulations indicate that the cement aerogel building envelope proposed in this study reduces the heating- and cooling-energy consumption by 32.54 % and 4.06 %, respectively, compared with traditional ones. Moreover, water welding can be used to heal broken cement aerogel materials and assist in the fabrication of larger-sized samples. After 20 h of selfhealing, the mechanical properties of the samples are restored completely, whereas the room-temperature (25 degrees C) thermal conductivity increases only slightly (by 0.002). Furthermore, the cost of the cement aerogel (4187.42 RMB/m3) is 69.7 % lower than that of commercial SiO2 aerogel. Therefore, the cement aerogel building envelope reported in this study can enable significant energy savings and carbon reduction in the building sector.

키워드