Sustainable development requires conservation of natural areas and materials while maintaining their capabilities to meet the needs of subsequent generations. Sustainable development depends on environmental protection (Gupta et al. 2021). Promoting sustainable development must be rooted in environmental protection in urban planning and urban development policies, industrial development policies, agricultural development policies, transportation policies and technology selection policies (Sathiparan et al. 2022). Construction industries adopted environmentally friendly materials due to increased mineral use and excessive extraction of minerals (Savadkoohi and Reisi 2020). The most common construction material, after water, is concrete. In concrete, cement is the main ingredient. The rapid growth of the building industry is driving the increasing demand for cement, increasing the production of cement clinker associated with high-energy consumption and more significant CO2 emissions (Steiner et al. 2022). The global construction industry emits 23% of the total CO2 produced by global economic activity (Thomas 2018). According to the worldwide cement market report in 2021, world production and consumption of cement are high and progression of the underlying annual growth expansion every year, which has increased steadily since 1970 (Usman et al., 2021). Due to the increased population and lack of ingredients of cement, there is a demand for cement manufacturing (Shaik et al., 2020). Clinker production demands high energy levels, limited to use as supplementary cementitious materials (SCM). Therefore, construction companies should be able to use alternative cementitious materials instead of traditional Portland cement (Jannat et al., 2022, Bhakar et al., 2020). Several previous studies have explored the possibility of reusing agricultural waste products as partial alternatives for cement (Sathiparan and De Zoysa 2018). To achieve sustainability, various SCMs must introduce against the growing pressures from society (Teixeira et al. 2022, Annaamalai et al. 2015, Akpenpuun et al. 2019).
Economic and environmental development, as well as sustainability, are directly impacted by waste generation and management (Rodier et al., 2019). Agricultural wastes are produced worldwide and contain many exciting components to create inorganic cementing binders. These materials are especially well suited to preparing inorganic binders (Zerihun, Yehualaw, and Vo, 2022). In addition, the waste produced from exploiting these leguminous crops has been dumped in unwanted landfills, negatively affecting the planet's ecosystems (Sahoo et al. 2021).
The Pigeon Pea, Cajanus cajan, is a perennial pulse known as arhar, tur, red gram, and gungo peas. In Tamil Nadu, the Pigeon pea is known locally as Thuvarai peas, mainly available in South Asia. For the Indian population, it is a common and high-protein food. According to Food and Agriculture Organization (FAO) statistics, Pigeon peas were produced in 14 regions in 2012, with India being the major producer (67.3%). The plantation area amounts to 9553 hectares, with an average production of 8.8 million tons yearly. However, pigeon pea stalks and pods are separated after processing and disposed of in the earth's surface-land disposal, causing environmental pollution (Luthra, Singh, and Kapur 2019).
In India, open-field burning is a common practice for disposing of agricultural waste after harvesting in rural areas, which releases greenhouse gases (carbon dioxide, methane, nitrous oxide and hydrofluorocarbons) and particles into the atmosphere. According to a study, 33.4% of all biomass burned in Asia was through open-field burning, primarily reported in India and China (Bheel et al., 2020). Nonetheless, burning agricultural waste under controlled conditions is environmentally friendly because it minimizes the air pollution caused by burning in the open (Son et al., 2017). In addition, when burned in a controlled manner, agricultural waste provides steam energy for electricity generation in developing nations (Sathvik, Suchith, et al. 2019). Furthermore, it beneficially results in residual ash, which could be recycled. The properties of farm waste ashes and their global availability suggest that these materials are used extensively in the construction industry (Salvo et al., 2015). However, agricultural waste ashes are difficult to accept in industrial settings due to insufficient data regarding the behaviour of concrete containing a mixture of agricultural waste with a wide range of farm waste ashes (He et al. 2020).
India generates more than 600 metric tons of agricultural waste yearly, creating a significant disposal problem (Somarriba Sokolova et al., 2018). Several studies have demonstrated the suitability of agricultural waste for use in concrete as a substitute for cement, fine, and coarse aggregates (Sathvik, Edwin, et al. 2019). It follows that using agricultural waste materials would contribute to eliminating the problem of pollutants and reduce construction materials' costs (Antony Godwin et al., 2018). It is possible to partially replace cement with ashes produced from the combustion of Pigeon pea stalks to fabricate sustainable concrete. Nevertheless, an appropriate characterization of Pigeon pea stalk ash can reduce the risk of fault or poor concrete performance and solve the problem of solid waste management (Joel 2010).
The durability, physical characteristics, and mechanical qualities of concrete made with pigeon pea stalk ash must also be thoroughly researched. Unfortunately, the research does not discuss the long-term cost-effectiveness or carbon dioxide emissions of concrete made with agricultural waste. (Rodier et al. 2019). Therefore, PPSA replacement levels in concrete had to be examined for their long-term properties.
This study is novel because it investigates the influence of pigeon pea stalk ash on the mechanical properties, durability properties, cost analysis, embodied energy, and carbon dioxide emissions of concrete. This study took various replacement levels of pigeon pea stalk ash as 2, 4, 6, 8 and 10%. This article used pigeon pea stalk ash as a cement substitute. A major advantage of adding pigeon pea stalk ash to concrete is that it enhances its compressive strength, split tensile strength and flexural strength. An original feature of the research was its consideration of social sustainability issues and energy efficiency in building design and construction. This study examines the long-term cost efficiency and reducing CO2 emissions from concrete containing pigeon pea stalk ash. Furthermore, it raised awareness about construction materials' sustainability and ecological development.
The main objective of this study is to investigate the following:
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To study several micro-analytical experiments, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), have been done to characterize PPSA.
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To determine the influence of pigeon pea stalk ashes (PPSA) on the hydration of cement binder was studied using X-Ray diffraction (XRD), and the mechanical and microstructural properties for a potential application in cementitious materials.
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The environmental, economic and technical effects of using these ashes in cement and cementitious materials manufacturing were conducted.
This paper also includes the following sections. The second section describes the various ingredients used for incorporating pigeon pea stalk ash as a substitute for cement in concrete. Then, the mix proportions found for M30 grade concrete as per the IS 10262: 2009 standard and details of strength-related experimental tests conducted on pigeon pea stalk ash replaced concrete. The third section compares the results of various tests between conventional concrete and concrete incorporated with pigeon pea stalk ash. Finally, the strength-and microstructural-related experimental studies are outlined in the fourth section.