Strength Developing in Clay-Andesite Brick

The objective of this work was to develop a more and better understanding of the strength developing in clay-andesite fired brick. The purpose was to improve the quality of the clay bricks that are handmade in the southern region of Ecuador to make them suitable for more widespread use in the local construction industry. To achieve our goal, we first physically, chemically, and mechanically characterized the “clayey” and “sandy” materials used in the fabrication of handmade bricks in the region. Second, the optimal mixture (OM): the optimal proportion between the amounts of “clayey” and “sandy” material was sought. Third, clay bricks were prepared using the OM, baked at 950°C, and characterized. In addition, bricks produced by regional artisans were characterized, and the results were compared with the results obtained for the bricks prepared using the OM. Our data reveal that the optimal mixture is 50% “clayey” material and 50% “sandy” material and that with this mixture, an average improvement in brick quality of 300% can be achieved;thus, the use of the OM makes it possible to expand the use of these bricks in the local construction industry and enables an environmentally friendly production process by reducing the intensive exploitation of regional clay deposits. This improvement is achieved by virtue of the anorthite enrichment that occurs in the solid solution, which results from the evolution of andesine. The anorthite contributes to the formation of a stronger matrix among the different grains of the material. Conditions are favorable for this enrichment process to occur when “sandy” materials with high contents of andesite, which is common in Ecuadorian soils, are used.

Applications of Compliance to Cost Ratio (C-CR) Analysis in the Determination of Optimum Mix of Insulating Bricks in Masonry

The scarcity of housing increases as population continues to rise all over the world. Despite government efforts at providing houses, yearly demand keeps on exceeding available houses and hence the hike in rent, the cost of erecting houses and the cost of building materials. This ultimately calls for a decisive solution. This study therefore applied compliance to cost ratio (C-CR) analysis in evaluating the optimum properties of fired ceramic bricks. The optimum mix proportions of waste glass (WG) and wood saw dust (WSD) in fired bricks, that will be suitable for housing constructions were hence determined. Fired clay brick samples which contained varied proportions of WG and WSD were examined for physical, mechanical and thermal properties in line with standard procedures. The results were compared with existing standards and property evaluation index, compliance level and C-CR were applied in analyzing the results obtained. It was observed that with increasing WG content, compliance level increased. Also, cost ratio and experimental cost of each brick sample trended upward. Sample with mix proportion;20 wt% WG, 5 wt% WSD and 75 wt% clay had compliance level of 94% and C-CR index of 7.81, hence chosen as optimum mix proportion for masonry bricks.

Recovery of Mining Wastes in Building Materials: A Review

The use of materials from waste in buildings compensates for the lack of natural resources, solves the problem of waste management and provides an alternative technique for protection of the environment. There are a large number of industrial wastes that are used for full or partial replacement of raw materials in some construction materials. This review assesses mining waste in concrete as a substitute for aggregates and cement;in fired bricks as a substitute for soil;and in road backfill as a substitute for soil. This paper reviews some mining tailings, mine waste rocks and some slags obtained in the exploitation and/or processing of some ores including iron, gold, lead, phosphate, copper, coal, etc. Different physical properties, mechanical properties, chemical properties, heavy metal content, mineralogic composition, geotechnical properties and environmental properties (leaching test) of the mine wastes were examined. The physical, mechanical and environmental properties of the materials obtained by substitution of raw materials by mine waste were examined and compared to reference materials. Mining waste in cementitious materials offers good compressive strengths, while the porosity of the concrete and/or mortar is a factor influencing its toxicity. As for the waste in fired bricks, fired at a temperature of 900°C or more, it offers convincing compressive and flexural strengths. The few research studies obtained on the use of mining waste in road embankments have shown that mining waste can be used as a sub-base layer and backfill as long as it is not toxic. In addition, several other mining wastes require special attention as substitutes for raw materials in construction materials, such as coltan, cobalt.

Recycling Bayer and sintering red muds in brick production:a review

Red mud(RM)is a solid waste generated from the extraction of alumina from bauxite.It is estimated that more than1.5 billion tonnes of RM are produced annually worldwide.Stockpiling and landfilling of RM is toxic for the environment due to the presence of high quantities of alkali-generating minerals and metal ions.The high cost of RM treatment and limited land availability encourage the recycling and reuse of RM as construction materials.In many developing countries,brick remains the ubiquitous building material.Thus,it is reasonable to use brick as a medium to accommodate a large amount of RM.In this review,the properties of RM are analyzed and their applications in bricks are discussed.Two common types of RM,namely Bayer red mud(BRM)and sintering red mud(SRM),are introduced along with the methods to produce bricks from them through firing,cementing,and geopolymerization.High alkaline-based BRM is particularly useful as a raw material to produce fired brick and geopolymer brick,whereas SRM,which contains more dicalcium silicate(C_(2)S)and some cementitious phases,can be favorably used to produce cementing brick.RM geopolymer brick normally has more strength(up to 51 MPa)than fired and cementing bricks,and good durability(no efflorescence)with low energy consumption and CO_(2)emissions.Finally,several solutions have been suggested to resolve the issue of the radioactivity of RM brick,and strict regulation of its application has been imposed in some countries,such as China.