This paper analyzes the effect of partial sand replacement by sugarcane bagasse ash in mixed mortars utilizing a 1:2:9 mix proportion by volume for Partial Replacement cement, lime and fine aggregate. The ash is characterized Partial Replacement by its particle distribution, pozzolanic activity, chemical composition, bulk density, moisture content and loss on ignition. The mortars are then produced with a constant water/cement ratio of 2.64 and a partial replacement of sand with sugarcane bagasse ash using different substitution percentages (0%, 5%, 10%, 15% and 20%). The mortars are characterized in the plastic state: water retention, bulk density and air content, and in the hardened state: capillary coefficient, tensile strength by bending test, axial compressive strength and flexural and longitudinal Young’s modulus. The statistical analysis of the results showed that the ash can be incorporated into mortars without causing significant alterations in its properties.
The construction industry is undoubtedly essential to a nation’s growth, playing a vital role within society by fulfilling its infrastructural needs (Ibrahim, Roy, Ahmed & Imtiaz, [1] ). However, the fulfilment of these needs has been consuming the natural resources of Earth at a relentless pace due to the manufacture of an enormous amount of material. Sand and cement are widely used in the construction industry and their feedstock needs to be extracted from the soil through mining. The literature (Brown & Lugo, [2] ) posits that the extraction of such feedstock generally induces detrimental impacts on the environment and results in long term environmental degradation. The degraded areas no longer present the ability to replace the soil’s organic matter, nutrients, biomass and propagules stock, altering the biological, physical and chemical characteristics of the explored site, making the soil sterile.
The best way to reduce the reliance on these resources and to conserve the environment, is by adopting alternative solutions, such as the use of industrial waste as feedstock (Alwaeli, [3] ), which can reduce the demand of natural resource extraction in addition to allowing for the potential discovery of materials with similar or even superior properties.
The large amount of industrial waste produced all over the world results in an extreme need for recycling, not only due to the raise on landfills disposal cost which reflects on the product cost, but also as a consequence of zero waste initiative, which should be the final aim of every future human activity (Faraone, Tonello, Furlani & Maschio, [4] ).
The waste incorporation as an alternative solution has shown satisfactory results in the literature, especially the utilization of sugarcane bagasse ash within the construction business (González-López et al., [5] ; Chen, Sun, Gau, Wu & Chen, [6] ; Lima, Varum, Sales & Neto, [7] ; Souza, Teixeira, Santos, Costa & Longo, [8] ; Akram, Memon & Obaid, [9] ; Cordeiro, Toledo Filho, Tavares & Fairbairn, [10] ). Previous studies analyze the characteristics of the ash and its possible application in constructions through additions and partial replacements of aggregate and binders in concrete, cement paste, mortars, ceramic materials and soil blocks.
Sugarcane bagasse is the main byproduct of sugarcane processing, which is widely utilized as boiler’s fuel in order to generate energy and such process generates waste such as bottom and fly ash. Considering that in the 2013/2014 harvest season around 652 million tons of sugarcane were crushed and that all bagasse was used to generate energy, then approximately 3.9 million tons of sugarcane bagasse ash were produced (Conab, [11] ).
A portion of this amount of ash returns to canebrake soil, even though it is a nutrient poor material with a difficult deterioration and it may contain heavy metals which can contaminate aquifers and the soil. The literature highlights that this practice is common amongst sugarcane farmers and it is considered environmentally friendly, however it seems that the use of pesticides is ignored; the combination of ash, filter cake and vinasse with pesticides is highly prejudicial to the soil (Sales & Lima, [12] ). When the ash is not properly disposed of, it can cause contamination of adjacent terrains, aquifers and can create health issues, resulting in severe social and environmental problems. Thus, since this waste does not have another use, the best option is to dispose of it in landfills (Frías, Villar & Savastano, 2011). The need for reducing the areas utilized for this waste’s disposal adds to the need to reduce the environmental impacts caused by it. This paper seeks to assist in this effort by analyzing the effects of the partial replacement of sand with sugarcane bagasse ash in mortars utilizing a 1:2:9 mix proportion by volume for cement:lime:fine aggregate. Firstly the ash was characterized to obtain its physical and chemical properties and then the bottom ash was used as a partial sand replacement at 5 different percentage values.