Keywords

1 Introduction

Various material production emits a huge amount of carbon emission; India emits 7.15% of carbon emissions by cement production globally [1]. These type of high carbon emission materials leads to greenhouse gases, and it is found that India is one of the major CO2 contributors, as it is producing 20% of overall GHG occurring globally [2]. Cement production is not ending with CO2 emission alone, it generates sulphur dioxide a colourless gas that is a major contributor to acid rain which creates an imbalance in the ecosystem, apart from this it also produces nitrogen oxides that cause air pollution which may create respiratory problem [3]. The CO2 emission produced by cement manufacturing is almost 0.8–0.9 times of actual manufacturing rate, that is 800–900 kg of CO2/T is produced, which may lead to a rapid increase in GHG emission [4]. In ancient days, we tend to use clay bricks for the construction of walls, which are made up of clay soil in this process initially the clay is dug, from the ground and later it is blended with a sufficient amount of water in it. The next stage is laying bricks in mould and the final stage is burning the bricks. During the burning, approximately 70–280 kg of carbon has been emitted for one ton of brick burning it also varies upon the type of fossil used for burning [4]. This was the procedure of clay brick manufacturing it is found that everyone started doing the same process for brick manufacturing, but at a later period due to the over usage of clay, it became an insufficient material, since it arrives from nature it was used as a fully sustainable material. When the material is forced under huge supply, it came under scarcity later to balance that cement bricks came into action [5,6,7]. In this paper, cement bricks are manufactured by adding cement, and sand together and placed in a mould once the brick attained its dry state, the comes curing here water curing takes place instead of burning the bricks. The compressive strength attained by cement bricks is high when compared to ideal clay bricks as this brick produces more strength it became the fastest connecting construction material that is used for wall construction. Cement bricks are classified as one of the best bricks for the construction of the wall in buildings, whereas clay bricks usage became half the initial usage, so it is found that the imbalance and demand in bricks are sorted out using cement bricks. Though it produces high strength on one side, the carbon emitted by cement bricks is getting increased on the other side. To reduce carbon emissions, cement should be partially replaced with some other binder that should undergo pozzolanic action, it is found that fly ash and GGBS can be partially replaced with cement to reduce that CO2 emission, and at the same time, the industrial by-products were also utilized properly [8,9,10]. To reduce the CO2 emission partial replacement for cementitious material such as fly ash, GGBS is implemented in general practices in the construction industry [11,12,13,14,15]. It is found that GGBS is a booming material that is used as a replacement for cement in concrete, almost 350 million tonnes of iron slag has been generated globally [16], so the same is taken into account here. Iron production is increasing rapidly, which poses an enormous amount of slag availability and still, there are places found with slag deposits on barren lands. Instead of depositing the slag as a waste material, it can be used as a properly reused material, so that it is treated as a valuable resource, on another hand, it is the best way to dispose the slag in a sustainable manner and it is also found that to grind the granulated blast furnace slag, only minimum amount of energy is required, that is 90% of energy is saved when its grinding is compared to Portland Cement production [17]. GGBS replacement is eventually placed with 50% as the replacement percentage takes action between 0.3 and 0.85 out of 1 [18]. GGBS won’t produce a high strength in the early stage as its hydration is different from Portland cement, even though it’s a sustainable replacement material for cement, the pores present inside the face at the centre affect the strength initially, but this slag replacement will produce a good strength in a later age that is approximately at 90-day strength. This replacement activity of slag in place of cement will reduce the amount of carbon emitted into the atmosphere, leading to the conservation of sustainable materials [19]. There are various factors that affect the cementitious property of GGBS, they are the fineness modulus, physical characterization, chemical characterization, amorphous content, etc. [14, 20]. Even though slag is a good cementitious replacement material, its optimum level of replacement should be properly studied because over-usage of GGBS will decrease the strength and durability of the overall material where slag is replaced [21,22,23]. It is found that unfired GGBS bricks will attain a high strength at a later age [24]. Based on the literature survey, it can be inferred that research under sustainable bricks has mostly consisted of fly ash and the partial replacement of GGBS in bricks is not commonly aware as same as fly ash. It is also found that GGBS is a proper cementitious material that can be replaced in place of Ordinary Portland Cement, which gives the same strength in case of a later age test apart from strength GGBS is a sustainable waste that has pozzolanic action in it. Hence, a combination of OPC, GGBS, and M-Sand is used to develop a sustainable brick in order to reduce the carbon emitted by cement bricks. Here, three trials with different mix ratios were carried out and the experimental solutions are derived at the end which gave comparatively good results than ideal clay bricks.

2 Material and Experimental Approach

2.1 Materials

GGBS is partially replaced with cement with some percentage so that the amount of cement used can be reduced which results in less carbon emission. Cement is the first binder used here, which in addition to M-Sand gives good strength, cement used here is OPC 53 Grade. GGBS is used as a second binder material used here. GGBS is a slag that is obtained by the steel manufacturing industry, as its size is comparatively less than OPC it settles in between the cement particles which gives proper bonding that results in high compressive strength.

This study used OPC, GGBS, and M-Sand for developing a sustainable brick that gave high compression strength. GGBS used here were in size between 15 and 16 μm. The chemical composition of the GGBS and OPC powders obtained from the X-ray fluorescence (XRF) analysis from various literature is expressing that the predominant oxide constituents of OPC are SiO2 (21.84%) and CaO (60.27%), whereas GGBS mostly consists of SiO2 (39.22%), Al2O3 (10.15%), and CaO (32.62%) [25]. In the XRD pattern of GGBS, it can be noted that the crystalline peaks of Quartz (SiO2), Calcite (CaCO3), and Alumina (Al2O3) are observed in the GGBS sample. The morphological and elemental composition of the GGBS sample was acquired from scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis, respectively. The SEM micrographs of GGBS particles are mostly tetrahedron in shape with rough surface textures [26]. The preliminary test is carried out for all three samples, and the specific gravity of OPC, GGBS, and M-Sand was 3.15, 2.2, 2.67, respectively. Pycnometer apparatus is used to find the specific gravity of M-Sand, and a Le Chatelier’s flask is used in the case of the other two cementitious materials mentioned above; these specific gravity plays a major role in calculating the volume of materials that need to be added.

2.2 Experimental Approach

In this study, three ratios are tried with raw materials of OPC, GGBS, and M-Sand, all three ratios were clearly mentioned in Table 1, and for all three variation volume of each material is calculated.

Table 1 Mix proportion of bricks
Full size table

The mix proportion mentioned in Table 1 is used to develop a brick specimen, using this ratio bricks are laid as three bricks per variation, as totally three types of bricks were developed here, and exactly 9 bricks were cast as per IS 13757 [27]. Once the brick is taken from mould, it is then allowed for air curing for up to the next 24 h, after that, it is taken for water absorption, and compression tests. All the bricks are casted by weight batching it is derived by volume proportioning condition, details of it were tabulated in Table 2.

Table 2 Mix proportion calculation of bricks
Full size table

2.3 Test Methods

There are totally two tests carried out on the sustainable brick, they are compression and water absorption test, and the results of the following tests will be mentioned here; initially, water absorption test is carried out as per IS 3495 (Part 2):1992 [28] all the bricks are taken and immersed in water for 24 h and after that, it is taken out and wiped by cloth and specimen is taken for weighing within 3 min from the time of taking out from the water the weight of all the trial specimen is provided in Table 3. The model representation of the brick is shown in Fig. 1. In the water absorption test, dry and wet weight for all 9 specimens is taken, and the percentage of each is derived from guidelines as per IS 3495 (Part 2): 1992 clause 4.1.4, and the results were tabulated in Table 3 [28]. It is founded that the minimum and water absorption at 4.40 and 7.17% along with this an average of each set is calculated and it is ensured that the difference between the same samples is not more than 5%, so the average of 3 sets is within the exact limit (Figs. 2 and 3; Table 4).

Table 3 Water absorption test results
Full size table
Fig. 1
A schematic illustration of a sustainable brick model. It is 190 millimeters wide, 90 millimeters long, and has a height of 90 millimeters.

Model of sustainable brick

Full size image
Fig. 2
Three photographs. A, a damp brick is positioned on a weight machine. B, a hand dries off the damp brick with a cloth. C. a dry brick is positioned on the weight machine.

Water absorption test of sustainable brick a dry weight, b wiping of brick, and c wet weight

Full size image
Fig. 3
Three photographs. A, a brick under a U T M for compression test. B, close view of the braking part. C, dial gauge reading.

Compression test a UTM with brick, b breaking point, and c dial gauge reading

Full size image
Table 4 Compression strength test results
Full size table

3 Result and Discussion

3.1 Compression Strength of Sustainable Brick

In this study, compression strength for all three trial bricks is carried out with the guidelines standard provided as per IS 1077:1992 and IS 3495 (Part 1): 1992 [28, 29]. This high strength is achieved due to a proper mix ratio and W/B ratio used in SGBT3, this high strength proves there are fewer voids present inside the brick, and apart from acting as a replacement material GGBS acted as an excellent filler material here. The proper filling is the main reason for the durability, as the filling material is properly bonded, the porosity level decreases, and as porosity decreases strength increases. It is not ended only with porosity even filling of cementitious material lead to proper hydration, on which the heat of hydration is controlled that reduces the shrinkage cracks during the setting of the top surface of the brick, usually shrinkage crack occurs due to the addition of Ordinary Portland Cement. Compression strength of all three bricks was plotted in a graphical manner in Fig. 4.

Fig. 4
A plotted graph of deflection versus sample. It includes three samples S G B T 1 series, S G B T 2 series, and S G B T 3 series. The S G B T 3 series has the highest range of 620 to 590, and 600 kilo newton.

Graphical representation compression strength of bricks

Full size image

3.2 Water Absorption of Sustainable Brick

The water absorption tests for all three trial bricks are below 12%, which proves that all three are good, non-porous bricks. SGBT1 has a water absorption result of 4.06%, which is very low, the standard ideal bricks are classified as bad water absorbers; in this case, all trials proved that they are standard bricks that absorb less amount of water through the inner pores and cavity. There should be minimum content of water absorption because the small micropores that penetrate water ensure that there is a gap in between the molecules to exhale the heat present inside the room that is constructed by that brick. SGBT2 absorbed water up to 5.5%, this is due to the increase in addition of Ordinary Portland Cement, hydration takes place when OPC is treated with water that tends to change the wet state to a dry state at the inner face of the brick, thus due to the proper hydration, development of partially dried lumps is reduced that results in good water absorption standard. SGBT3 attained 7.3% of water absorption, which is exactly half the percentage mentioned in the codal reference, this is an accurate and appropriate result that proves that among three bricks, this is the perfect mix ratio and it also denotes that GGBS will reduce the water absorption pores when its optimum level is maintained exactly, in the same way, if it crosses the optimacy then it will just act as a filler material instead of acting as a cementitious material. All three variation bricks’ water absorption results are plotted in a graphical presentation in Fig. 5.

Fig. 5
A plotted graph depicts the percentage of water absorption versus the sample. It includes three samples S G B T 1 series, S G B T 2 series, and S G B T 3 series. The S G B T 3 series has the highest range of 7.11 to 7.00, and 7.17 percentages.

Graphical representation of water absorption of bricks

Full size image

4 Conclusion

  • It is found that the partial replacement of cementitious material will increase the weight of the brick, from ideal clay brick, because the particle size of the replacement material is very less when it is compared to OPC53.

  • There should be a proper limitation for the usage of any replacement materials, once this got more percentage in volume; then the amount of water consumption will get increase which will lead to the over addition of superplasticizers.

  • Partial replacement of cement as GGBS of 30% gave a compression strength of 24 MPa, which is an average of three specimens cast with the same proportion.

  • Water absorption is a maximum of 7.11% in sample SGBT3, this proved that the brick is a partial non-porous brick that only penetrated less water.

  • Finally, the sustainable brick by industrial by-product gave expected results, within the expected time and the important learning from this study is, these types of work will increase the utilization of waste materials, which changes these dump materials into renewable materials