Comparative Studies of the Confined Effect of Shear Masonry Walls Made of Autoclaved Aerated Concrete Masonry Units

Abstract

Confined walls are popular in areas exposed to seismic action. The advantage of such structures is increased load-bearing capacity, ductility, and energy dissipation. Confined masonry walls are also used to restrain the intensity of cracking and improve load-bearing capacity in areas exposed to seismic action. This paper describes the research on 18 confined walls and presents a comparison with research on unconfined walls (referenced models). The confined models were classified into three series: HOS-C-AAC—without openings and with confining elements around the perimeter; HAS-C1-AAC with a centrally positioned opening and circumferential confinement; and HAS-C2-AAC with a centrally positioned window opening and additional confinement along the vertical edges of the opening. The area of the window opening was 1.5 m2. All walls were made of autoclaved aerated concrete (AAC) masonry units of the nominal density class of 600. The walls were tested under initial compressive stresses σc = 0.1; 0.75; and 1.0 N/mm2. The reference models without confinement (six models of the series HOS-AAC without openings and the series HAS-AAC with openings) were prepared from the same masonry units, had almost the same outer dimensions, and were tested under the same initial compressive stresses σc. The analysis was performed for the morphology of cracks, stress values at the moment of cracking and failure, stiffness, and angles of shear strain. The morphology of cracks was found to depend on initial compressive stresses and the presence of an opening. A significant increase in compressive stress leading to cracks and failure stresses was observed with increasing values of initial compressive stresses. As the wall behavior was clearly non-linear, the bilinear relationship described by energy dissipation E, stiffness at the moment of cracking Kcr, and maximum displacement uu was proposed to be included in the engineering description of the relationship between horizontal load and displacement of confined walls. Confinement along the vertical edges of the opening having an area of 1.5 m2 (acc. to EN 1996-1-1) increased the maximum forces Pmax by ca. 45% and marginally affected the ductility of the wall when compared to the elements with circumferential confinement.

Enhancing Thermal Performance of Autoclaved Aerated Concrete (AAC) Incorporating Sugar Sediment Waste and Recycled AAC with Phase Change Material-Coated Applications for Sustainable Energy Conservation in Building

“…AAC stands out for its remarkable ability to achieve approximately 50% energy savings without additional thermal insulation materials, positioning it as a potential key player in energy conservation [10][11][12][13][14][15]. Its lightweight and highly porous structure, with about 80% volume comprised of pores, provides lower thermal insulating capacities, higher heat resistance, and reduced shrinkage compared to traditional concrete [16][17][18][19][20][21][22][23][24][25][26][27], contributing to enhanced energy efficiency in buildings.…”

“…By utilizing residual materials from industrial procedures, including expanded perlite waste (EPW) [15], efflorescent sand and phosphorescent slag [30], iron ore tailings [31], air-cooled slag [32], crushed siliceous stone [33], lead-zinc tailings [34], coal bottom ash [35], copper tailings and blast furnace slag [36], calcium fly ash and natural zeolite [37], waste from sugar sediment [38], and black dust [39,40]. AAC properties are enhanced, leading to economic and environmental benefits [15][16][17][18][19][20][21][22][23][24][25][26][27]. For instance, incorporating EPW as a substitute for ground quartz sand reduces thermal conductivity without sacrificing compressive strength [15].…”