The concrete industry is one of the biggest consumers of natural resources because the sustainability of the concrete industry is threatened. Environmental and economic concern is the biggest challenge facing the concrete industry. In this paper, issues of environmental and economic concern are addressed through the use of saw dust ash as partial replacement of cement in concrete. The cement was replaced by sawdust as 5%, 10%, 15% and 20% by weight for the M-25 blend. Concrete specimens were tested for compressive strength, durability (water absorption) and density at 28 days of age and the results obtained were compared with those of normal concrete. The results concluded the permissibility of using saw dust ash as a partial cement replacement to 10% by weight for particle size in the range of 90 microns.
Concrete is the most popular building material in the world. It is known that concrete is the most extensive structural material because of its quality to conform to various geometric configurations. It is a set of cement, fine and coarse aggregates and water. More than 300 million tons of industrial waste are produced annually by various industrial and agricultural processes. These materials have disposal problems, health hazards and aesthetic problems. Global cement consumption is too high because of its extensive use in concrete. More than 5 billion tons of cement are produced in the world per year. However, cement production is decreasing limestone reserves in the world and also requires a lot of energy consumption. River sand has been the most popular choice for the fine aggregate component of concrete in the past, but overuse of the material has led to environmental concerns, depletion of insurable river sand deposits and a concomitant price increase in the material. Therefore, there is a need to look for local materials as alternatives for the construction of functional but low-cost buildings in both rural and urban areas. Construction industries are under stress to identify alternative materials to replace the demand for natural sand and cement. On the other hand, the advantages of the use of by-products or aggregates obtained as waste are manifested in the aspects of cost reduction of waste and waste management, reduction of production costs and increase of concrete. To overcome the stress and demand of fine natural aggregates and cement, researchers and construction professionals have identified some alternative materials such as fly ash, slag, limestone powder, siliceous materials, sawdust. In India, attempts have been made to replace cement with saw dust ash. Concrete is by far the most commonly used construction material for man and studies indicate that it will remain so for years and decades to come. Approximately 5 billion tons of concrete are used worldwide each year, enough for about one ton per person per year, at a volume of about 400 liters per person. This versatility of the concrete is due to the fact that from the common ingredients, namely cement, aggregates and water, it is possible to adapt the concrete properties to meet the demands of any particular situation. Advances in concrete technology have paved the way for making the best use of locally available materials by judicious dosage mixing and proper workmanship to give rise to concrete that meets performance requirements.