Materials Science Forum Vol. 1023

Abstract: This paper investigates the combined effect of waste soda-lime glass sand and glass fiber on the physical and mechanical properties of none-autoclaved aerated concrete (NAAC). The use of both soda-lime glass sand and glass fiber can provide silica-rich materials in the aerated concrete and can enable the elimination of an autoclaved curing by enhancing the physical and mechanical properties in aerated concrete. In this study, a total of six mixture proportions were designed to evaluate these properties in NAAC. The mixture parameters included the partial substitutions of normal sand with soda-lime glass sand (0%, 15%, and 30%) and glass fiber (1%, 2%, and 3%). A series of tests were conducted to determine density, absorption, porosity, and both compressive and flexural strengths of the NAAC. Test results present that the increase of glass sand content leads to the increasing of both compressive and flexural strengths. Moreover, the combination of the use of glass sand with glass fiber also increases the strength up to 2 times (the mixture of 30% glass sand and 3% glass fiber). Furthermore, test results indicate the relatively good relationship between the density, porosity, and of NAAC with good accuracy.

Abstract: Brick as a material is of vital importance in the construction industry, however, the burning processes for its preparation contribute to environmental pollution and the generation of greenhouse gases; for this reason, the present research has as aims to propose quality traditional materials for sustainable buildings through the design of soil-cement mixtures in making brick using raw materials from the amazon region of Ecuador: Centza mine (MC) and Quiringue mine (MQ) and improve the mechanical properties of the brick by incorporating carbon nanotubes, which have been dispersed in two aqueous media, sodium naphthalene sulfonate (NSS) and calcium chloride (CC) in percentages of 0.5%, 1% and 1.5%. The characterization of the raw material (analysis: physicochemical and mineralogical) was of great help. The optimum percentage of cement and water was determined through simple compression tests and soil compaction respectively. The different combinations were tested at indirect traction strength at ages 7, 14 and 28 days, determining an optimal mixture for each group of combinations, in this way the simple compressive strength of bricks has been estimated using the Griffith criterion and validation of results by finite element method applying the CivilFEM software, obtaining a resistance of 4 MPa in mixtures of SC-Ar1, 6.3 MPa in combinations of MWCNTs NSS-9 and 5.3 MPa in mixtures of CC-4 MWCNTs, increasing resistance by 57.5% and 32.5% with respect to soil-cement bricks and qualifying them as suitable for use in construction according to standars.

Abstract: The construction industry has focused on trying to minimize and control the environmental impacts caused within the process of production and manufacture of fired bricks, for this reason the present research proposes five different alternative mixtures for the elaboration of ecological bricks, four of these based on soil-cement and one obtained through a geopolymerization process, using raw materials from the amazon region and the southern highlands of Ecuador, such as soil from the Centza mine (MC), sand from the Quiringue mine (MQ), organic correctors of husk rice (RH ), peanut shell (PS), natural gypsum (G) from the Malacatos sector and fired brick residues from the same sector. The raw materials were characterized (analysis: physicochemical and mineralogical); the soil-cement-based combinations used different percentages of substitution of organic correctors and gypsum, the optimum percentage of water and cement was determined through the compaction test and resistance to simple compression respectively, the samples were cured and tested at ages of 7, 14 and 28 days. In the geopolymerization process, an alkaline solution NaOH was used in different concentrations of molarity and solution contents, the specimens were cured at temperatures of 90 °C, 120 °C, 150 °C, 180 °C and 200 °C. The different combinations were subjected to indirect traction with the purpose to determine the optimal mixture and subsequent estimation of the compressive strength of bricks applying the Griffith criterion, the results were validated by the finite element method, obtaining strengths of 4 MPa in the combination soil-cement sand (SC_Ar1), in soil-cement rice husk (SC_RH2) and soil-cement peanut shell (SC_PS2) mixtures its resistance is 3 MPa, while in the soil-cement gypsum (SC_G4) mixture the resistance is 6.90 MPa and finally the resistance in geopolymeric mixture (GBW) is 13.75 MPa; In this way, the optimal combinations comply and increase the resistance to simple compression of bricks by 35% the SC_Ar1 mixture, 130% in the SC_G mixture with respect to the spanish standard and 129% the GBW mixture with respect to the ecuadorian standard.