Production of Aerated Foamed Concrete with Industrial Waste from the Gems and Jewels Sector of Rio Grande do Sul-Brazil

Abstract

Abstract:The use of solid waste for the development of new building materials has been an alternative to reduce environmental impacts through the preservation of natural resources. In this context, this paper evaluates the possibility of using agate gemstone waste, called rolled powder, which basically consists of silica (SiO 2 ), in the manufacture of aerated foamed concrete blocks completely replacing the natural sand. Preformed foam was used as the air entrained by mechanical stirring with a mixture of natural foaming agents derived from coconut. To produce test specimens, the water/cement ratio and foam concentrations were varied, with three and four levels, respectively. The specimens were left for 28 days at room temperature to be cured, and then underwent analysis to determine their compressive strength, density, and the distribution of air-voids. The experiments demonstrated that the best water/cement ratio was 1.28 for 18% (of total solid mass) addition of foam, which generated a sample with a density of 430 kg/m 3 , and a compressive strength of 1.07 MPa. The result for compressive strength is 11% smaller than the requirements of the Brazilian standard (NBR 13438) for autoclaved aerated concrete blocks, but the results are promising.

Characterization and Use of Construction and Demolition Waste from South of Brazil in the Production of Foamed Concrete Blocks

“…The amide 90, known as coconut oil diethanolamine condensate , is a mixture of the diethanolamides of the fatty acids that constitute coconut oil. This proportion was established in former studies [30]. A mechanical stirrer was used to produce foam with a density of 75 kg/m 3 .…”

“…Four levels of FA and three levels of CDWG were used, while all other parameters were held constant. The water/cement (W/C) ratio was maintained constant by varying the amount of water, and it was considered that 98% of the foam is water [30]. Five output variables (responses) were analyzed: compressive strength (CS), wet bulk density (WBD), dry bulk density (DBD), air void (AV) and water absorption (WA).…”

Rice Hulls as a Renewable Complex Material Resource

“…Rice hulls ash cannot compete with mineral analogues of industrial manufacturers; however, it is available for the solution of regional problems in agricultural regions. Use of solid waste for the development of new building materials is known to be an alternative that reduces environmental impact through preservation of natural resources at a regional level [25].…”

Evaluation of the Physical and Mechanical Properties of Autoclaved and Foamed Concrete Blocks Marketed in Passo Fundo/RS Brazil

“…The characteristics found can be related to the formation properties of the pores, While the AACB has the formation of a larger number of voids with smaller diameters, the FCCB has a smaller number of pores, but these are of a larger diameter, which can be seen by comparing the densities of the samples. Another characteristic to be emphasized is the capillarity of the pores since the AACB has more spherical and separated pores and the FCCB presents amorphous aspects connected by capillaries, directly affecting its strength, since its structure is directly connected with the distribution of forces within the matrix (CORTELASSI; TORALLES-CARBONARI, 2008;FAVARETTO et al, 2017;PEDRO et al, 2017). This difference between the capillaries of the autoclaved concrete block and the foamed concrete block is shown in Figure 4.…”

“…This is achieved by vigorous stirring or pneumatic pressure on the foam agent, which may be a surfactant or a protein. The air volume depends on the mixing regime and the time taken to do this, the concentration of the reagent, the temperature of the process, the volume of water added and the characteristics of the materials (PEDRO et al, 2017).…”