Fundamental Properties and Thermal Transferability of Masonry Built by Autoclaved Aerated Concrete Self-Insulation Blocks

Abstract

This paper performed a detailed study on the fundamental properties and thermal conductivity of autoclaved aerated concrete (AAC) self-insulation block, and the mechanical properties and heat transfer resistance of the AAC self-insulation block masonry. Different kinds of joints and the plastering surface were used to build the masonry specimens. The distinctive feature of the blocks and mortars is the lower thermal conductivity with expected strength. Compared to those with larger thickness of insulation mortar joints, the masonry with thin-layer mortar joints had better compressive performance and lower shear strength. The compressive strength of masonry was related with the block and mortar strengths, the shear strength of masonry along mortar joints was related with the mortar strength. The stress–strain relationship of masonry in compression could be predicted by the similar expression of conventional block masonry. The tested heat transfer coefficient of AAC self-insulation block masonry with thickness of 250 mm without plastering surfaces was (0.558 ± 0.003) W/(m2·K). With the plastering surfaces, the heat transfer coefficient reduced by 4.4% to 8.9%. Good agreements in values of heat transfer coefficient existed by using the test, theoretical computation and ANSYS (ANSYS Inc. Canonsburg, PA, USA) analytical methods. Based on the extensibility analyses, the heat transfer coefficients of AAC self-insultation block masonry with different thickness are proposed. The best thickness is proposed for the outer walls of residential buildings in different cold zone to meet the design requirement of energy conservation.

On the Seismic Performance of Autoclaved Aerated Concrete Self-Insulation Block Walls

“…The dimension of block was 600 mm long, 300 mm height and 250 mm wide. Based on the tests of the blocks [ 15 ], the dry density was 558 kg/m 3 , the compressive strength was 4.1 MPa, the water absorption was 63.5%, and the thermal conductivity was 0.11 W⁄(m·K). As per the specification of China code GB 11968 [ 1 ], the block belongs to the superior product with class of strength A5.0 and density B06.…”

“…Two kinds of masonry mortar were used for the construction of wall specimens [ 15 ]. One was the thin-layer mortar for the joints with thickness of 5 mm.…”

“…The basic mechanical performances of AAC self-insulation block masonry were measured as per China code GB/T 50129 [ 18 ]. The test methods for the compressive strength and the shear strength along joints of the AAC self-insulation block masonry are concretely presented in related researches reported previously [ 15 ]. The masonry with thin-layer mortar joints had a compressive strength of 1.99 MPa and a shear strength along joints of 0.25 MPa.…”

“…Before seismic testing, all specimens were tested to measure the heat transfer coefficient to gather the test data. The thermal-insulation test method was reported in previous studies [ 15 , 19 ]. As presented in Table 1 , the heat transfer coefficient of block masonry is almost the same as previous tests.…”

“…One of them is the AAC self-insulation block. Based on previous studies, the AAC self-insulation block has features of much lower thermal conductivity under the premise of ensuring rational mechanical properties [ 15 ]. Meanwhile, the thermal insulation mortar used for AAC block masonry was also developed [ 16 , 17 ].…”