Influence of Aluminium and Autoclaving Temperature on the Properties of Autoclaved Aerated Concrete

Autoclaved aerated concrete (AAC) prepared by the mixing of ordinary Portland cement, lime powder, sand, aluminium powder and water. This study covers the variation of physical, mechanical and functional properties of autoclaved aerated concrete with autoclaving temperature and aluminium content and compared with that of normal weight cement mortar sample. In this work, two dosage of aluminium content of 0.4% and 0.8% of the dry weight of ordinary Portland cement and three different autoclaving temperature of 160oC, 180oC and 200oC were used. AAC sample with 0.8% aluminium and 160oC temperature had unit weight of 1490kg/m3 which was lowest among all samples including the control or normal weight cement blocks. Weight reduction of AAC sample was 31.53%. AAC sample with 0.4% aluminium and 200oC autoclaving temperature gave maximum compressive and tensile strength of 19.4MPa and 1.81MPa respectively which were close to that of normal weight concrete and strength of AAC increased with autoclaving temperature and decreased with aluminium content. In this research, the functional propertiesof AAC, absorption capacity was much higher than normal weight concrete and this capacity was increased with aluminium content and with decreasing autoclaving temperature and unit weight of AAC. For AAC with 0.8% aluminium and 160oC temperature gave maximum water absorption capacity (=9.93%). Again, surface absorption rate was higher for first 12hours and with time it would be constant because of its saturated position. Journal of Engineering Science 12(3), 2021, 11-17

The Physical and Mechanical Properties of Autoclaved Aerated Concrete (AAC) with Recycled AAC as a Partial Replacement for Sand

The application of AAC has increased considerably in Malaysia since the 1990s. The usage of AAC has some advantages, but it also has negative environmental impacts since rejected concrete will become landfill. This study aimed to use AAC waste powder as a material that would partially replace the sand content to produce a new form of Autoclaved Aerated Concrete (AAC). The physical and mechanical properties of the newly developed AAC were investigated. This paper presents improved mechanical and physical properties of the new form of recycled AAC concrete. Besides these improvements, using recycled AAC could lower production costs. Furthermore, the usage of this recycled waste powder is both economically and environmentally advantageous. This study found that when recycled AAC was substituted for sand, AAC with a fine recycled powder content of 30% had a compressive strength that was around 16% higher than conventional AAC and between 29% and 156% higher than any value attained utilizing an industrial waste product. This study also confirmed that the greater strength could be identical to a higher tobermorite phase and that the recycled AAC surface showed a finer crystalline morphology.

Influence of Waste Tire Particles on Freeze–Thaw Resistance and Impermeability Performance of Waste Tires/Sand-Based Autoclaved Aerated Concrete Composites

Waste tires/sand-based autoclaved aerated concrete (SAAC) composites were prepared by mixing waste tires, which have different particle sizes and content. The physical performance, mechanical properties, freeze–thaw resistance, impermeability performance, phase composition, and microstructure of waste tires/sand-based autoclaved aerated concrete composite materials were examined. The results demonstrated that the 750-μm-sized waste tire particles on the surface of the SAAC composite did not agglomerate. Moreover, these particles did not damage the pore structure of the composites. The SAAC composites, with a relatively high compressive strength and low mass-loss rate, were obtained when the contents of waste tire particles ranged from 1.0 to 2.5 wt.%. For composites prepared with 2.0 wt.% of 750-μm-sized waste tire particles, the optimal compressive and flexural strength values were 3.20 and 0.95 MPa, respectively. The increase in the rate of water absorption on SAAC composites was lowest (i.e., 16.3%) when the soaking time was from 24 to 120 h.

Experimental and Numerical Studies on the Behaviors of Autoclaved Aerated Concrete Panels with Insulation Boards Subjected to Wind Loading

Autoclaved aerated concrete panels (AACP) are lightweight elements in civil engineering design. In this paper, experiments and numerical analyses were conducted to study the flexural behavior of an enclosure system that consisted of AACPs and a decorative plate. A full-scale test was conducted to investigate the behavior of the enclosure system under wind suction. Load–deflection curves and load–strain relationships under different wind pressures were recorded and discussed. The effects of thickness, reinforcement ratio, and strength grade on the flexural behavior of AACPs were numerically investigated. Based on the numerical results, we found that the flexural behavior of AACPs can be improved by increasing the thickness or the reinforcement ratio. A comparison of finite element and theoretical results calculated using American and Chinese design formulae was conducted, and the results indicated the existing design formulae can conservatively estimate the major mechanical indices of AACPs.

Evaluation of Non-Autoclaved Aerated Concrete for Energy Behaviors of a Residential House in Nur-Sultan, Kazakhstan

Autoclaved aerated concrete (AAC) is commonly used as a modern, energy-efficient construction material in Nur-Sultan, Kazakhstan—the second-coldest national capital in the world after Ulaanbaatar, Mongolia. The autoclave curing method used to manufacture the AAC has potential risks and is environmentally costly because of its high-pressure and -temperature operation. Therefore, for phase I and II studies, non-autoclaved aerated concrete (NAAC) was cast, and its properties were evaluated in terms of compressive strength, density, porosity, and thermal conductivity. Moreover, the thermal conductivity prediction model of NAAC was successfully developed. In this Phase III study, the energy behavior of the NAAC was evaluated by energy simulation for a typical two-story residential house model in Kazakhstan. Different wall materials, such as fired brick and normal concrete, were adapted to compare the energy performance of NAAC. Finally, the annual heat loss and amount of heat transferred through the wall of the house were calculated to cross-check the energy-saving effect of NAAC. It was found that the NAAC conserved energy, because the heating and cooling loads, annual heat loss, and amount of heat transfer of NACC were lower than those of fired brick and normal concrete.

Analysis of production capacity planning to meet the consumer request using the Rough Cut Capacity Planning (RCCP) method in PT. Maccon Generasi Mandiri Makassar, Indonesia

Maccon Generasi Mandiri Makassar company is one of a manufacturing company engaged in the production of light brick AAC (Autoclaved Aerated Concrete). PT. Maccon Generasi Mandiri Makassar has a production capacity of 15024 〖 m〗^3 in a month or 180288 〖 m〗^3 in a year. However, with this capacity, the company is often unable to meet high consumer demand of 181450 〖 m〗^3 in a year due to less than optimal engine performance, a number of hours of work and an unbalanced workforce in the producing light brick of ACC (Autoclaved Aerated Concrete). This requires the company to plan the optimal production of capacity in order to fulfill the consumer demand in a timely and appropriate amount so that the expected of company profits will be increased. The purpose of this research is to plan production capacity in the future based on the demand rate of the consumer using the Rough Cut Capacity Planning (RCCP) with the method is Bill of Labor Approach (BOLA) technique. Based on the data processing which has been done, the recommended made were a combination of engine additions and working time. This is realized to fulfill the lack of production capacity. For the January Period = 19872 hours/month, February = 19008 hours/month, March = 19872 hours/month, April = 19008 hours/month, May = 18144 hours/month, June = 18144 hours/month, July = 19872 hour/month, August = 18144 hours/month, September = 17280 hours/month, October = 18144 hours/month, November = 18144 hours/month, December = 17280 hours/month.

A Comparative Study on Conventional Clay Bricks and Autoclaved Aerated Concrete Blocks

In India, traditional clay brick is the most common filler material used in building. The materials used in construction have a significant influence on both the constructed environment and the project’s ultimate cost. Autoclaved Aerated Concrete (AAC) has recently emerged as a viable alternative to clay and fly ash bricks. In this work, a comparison of clay bricks and AAC blocks is explored. Although AAC blocks have been utilised in building since 1924, they now account for just 16-18% of all construction in India. AAC blocks have desirable mechanical qualities in proportion to their low bulk density, improved thermal and acoustic properties, light weight, and ease of installation, making them an obvious alternative to replace traditional clay bricks. The purpose of this study is to demonstrate the potential of AAC blocks as an infill material to replace clay bricks and to encourage its usage in construction to create more energy efficient and sustainable structures. AAC blocks’ potential as an infill material in hilly areas is discussed.

Comparison of Influence of Superficial Strengthening with FRCM System and Kind of Mortar Type on Shear Strength of Autoclaved Aerated Concrete Masonry

This paper describes a comparison of results from testing shear strength of autoclaved aerated concrete (AAC) walls strengthened with superficial strengthening with the results of tests of walls made of various types of joints and mortar. The initial and characteristic shear strength and the angle of internal friction were compared. The test elements were made using two types of mortars, three types of joints, and two methods of reinforcement. The models were made using masonry units in the SOLBET OPTIMAL system. SOLBET 0.1 mortar, intended for thin joints, as well as SOLBET SMART polyurethane adhesive were used. Typical joints with a width equal to the thickness of the wall, shell bedded joints and joints without mortar were made. Models with typical joints were also tested as reinforced on one and two sides with the FRCM system, using the mineral cement matrix PBO-MX GOLD MASONRY and the PBO-MESH GOLD 22/22 mesh. A total of 56 models were tested in accordance with the requirements of PN-EN 1052-3: 2004. A significant influence of with superficial strengthening as well as the type of mortar and the construction of joints on the individual parameters of shear strength was demonstrated.