In the current environment adaptability scenarios, natural aggregates are being added to the mixture at a value of roughly 70%–80% by volume to maintain the dimensional stability of the concrete and to reduce the amount of Portland cement [1-3]. Aggregates gives high-volume stability and it is also cheaper than cement [4, 5]. In many countries, as the number of constructions is increasing, the demand for concrete is also increasing [6]. The excessive use of naturally available materials for concrete production is one of the worrying issue associated with environmental degradation [7-9]. Every year, nearly 40 billion tons of aggregate is being used as a mixing material in concrete [10, 11]. The extraction of river sand in large amounts will cause the depletion of river base [12-14]. The result of river sand extraction creates the vital challenge in several nations which include India, Thailand, China etc. [15, 16]. Regarding this, an immediate alternative for aggregate is required.
Granite waste is obtained as a by-product of mining industry. In some cases it can be used partially and in some cases it can be used completely as a replacement for aggregate. Granite waste is a combination of slurry and solid [17]. The granite cutting waste is disposed in dumpsites, which is actually 58% of the overall output of the plant [18]. Unfortunately, the increase in deposition of non-decomposable material causes contamination in the communities and major environmental threats [19, 20]. Air pollution is caused by the colloidal waste when it becomes dry dust by losing its moisture which can be blown by wind [20-22]. Furthermore, in the quarry sector, stockpiling and the deposition of stone slurry is a major issue [23-25]. The granite particle waste can be used as an ingredient in concrete which results in waste management processes that are both cost effective and eco-friendly .
The characteristics of fine aggregates have a major impact on concrete’s performance which is 20%-30% of concrete volume [26, 27]. A lot of attempts have been made for the determination of mix design of better concrete preparation by substituting granite particles waste in place of aggregates[26, 28] with 25% of sand replaced with granite particle waste. The concrete's 28-day compressive strength has been decreased by 11% which was found by Vijayalakshmi and Sekar [20]. According to Singh et al. [19], it was observed that using granite particle waste instead of sand enhanced the concrete's strength by up to 30%. In addition to that, there is better resistance to water penetration for the concrete which is made from granite waste [9]. The early research demonstrates that using granite particles in place of fine aggregates like river sands offers a sustainable way to dispose of industrial waste while maintaining the unique features of concrete [27]. Also, a study found that replacing up to 25% of fine aggregate by granite particles increased concrete’s mechanical characteristics [29].
Durability characteristics of concrete such as rapid chloride penetration test (RCPT), water absorption, carbonation sulphate resistance, electrical resistivity were increased when there is replacement of 25% granite slurry waste concrete in place of sand [30]. A considerable percentage of granite slurry in concrete mix improves plastic and drying shrinkage when compared to nominal mix [11]. Investigation revealed that granite slurry waste has cementicious qualities because of the granite slurry's properties, it may be used in concrete, which satisfies both economic and environmental concerns [5, 30]. The use of waste granite slurry in concrete is a more effective and eco-friendly way to dispose granite waste.
Even though there are a lot of studies on the application of waste granite slurry in concrete, most of them are confined to a single w/c ratio and the mechanical properties of concrete having granite waste, as proven by the work studied. Therefore, with two distinct w/c ratios of 0.5 and 0.4, the mechanical qualities (flexural and compressive strengths) and durability properties (abrasion resistance, water permeability) with granite slurry as partial/complete substitute for natural sand were investigated in this systematic study [14, 31]. Concrete containing granite particles waste was also subjected to NDT tests (ultrasonic pulse velocity and rebound hammer) [30]. The fine aggregate has been replaced by granite slurry in the following percentages: 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%. Also, microstructure examination was done using scanning electron microscopy for the visual interpretation.
1.2. Research objectives
The objectives followed for the current study are:
- To evaluate physical and mechanical attributes of used raw materials.
- To evaluate the durability and mechanical properties of concrete utilising granite slurry as a partial or complete substitution for natural river sand.
- To determine the non-destructive property of concrete utilizing granite slurry as partial or complete substitution for natural river sand.
- To analyse microstructure of modified concrete using scanning electron microscopy
1.3. Overview of experimental programme
For the purposes of carrying out the research, the following techniques has been used
1. Comprehensive literature survey has been done for published works.
2. Required materials and additives were procured.
3. Physical properties of the used raw materials were evaluated.
4. Trial mixes were prepared with varying percentage of granite slurry waste.
5. Casting were carried in desired mould (cube/cylinder/beam specimen).
6. The mechanical and durability tests were carried out.
7. Analysis of results and discussion.
8. Conclusions and recommendations.