Analysis of Strength Parameters of Paving Blocks with inclusion Sea Sand

Start with the Scarcity of materials in concrete so sand has steadily gained prominence as the most frequent building material used in the construction industry. As the population increases, so does the need for residential and commercial space. The most essential resource for mankind, river sand, is being mined out of riverbeds more frequently. One ton of regular Portland (OPC) cement is produced in India for every tonne of CO2 that is released into the environment. By substituting cementitious materials like fly ash and ground-granulated blast furnace slag for ordinary cement, we can lower the number of greenhouse gases that are emitted into the atmosphere. To create sustainable concrete pavement blocks, this experimental work has been carried out with the use of cementitious elements including fly ash and ground granulated furnace slag (GGBS) as a replacement for cement, and to enhance public transportation, this research is focused on creating paver blocks that contain sea sand as fine aggregate. This experimental investigation was conducted to investigate different sustainable concrete strength properties with 0% sea sand, 50% Sea Sand and 50% M sand, and 100% sea sane used to partially replace the mix proportion. Results of mechanical parameters such as Compressive strength, water absorption, abrasion resistance, and carbonation of these sustainable concrete pavement blocks are presented also a cost analysis of paving blocks was evaluated.


INTRODUCTION
Making concrete paver blocks with Geopolymer concrete is an environmentally friendly process called "Green Paver Block."[1], [2].Cement concrete is currently the second most consumed commodity on earth due to the rapid growth of infrastructure.Because of their quick and simple installation, superior appearance, and finish, cement concrete paver blocks have become the preferred option.Precast 1282 (2023) 012002 IOP Publishing doi:10.1088/1757-899X/1282/1/012002 2 concrete paver blocks are the most popular option for paving footpaths, parking lots, bus stops, industries, etc.The majority of constructions use river sand as fine aggregates, and as demand rises, sand availability decreases.This leads to illegal sand grabbing from river beds, and the demand for river sand in construction is currently very high.Therefore, it has been very difficult to discover a substitute for river sand that has the same benefits as river sand, such as ease of availability, eco-friendliness, and low cost [4]- [6].Sea sand, a material that may be utilized for building as well as concrete components like paver blocks, is an alternative to river sand [7]- [9] Because sea sand contains salt, replacing it with concrete affects the building and concrete products in numerous ways.Further research has been done to establish how the chemical and physical differences between river and sea sand affect the mechanical properties of concrete [11].To improve concrete durability, sea sand was added to the mix when creating ultra-high-performance concrete.The development of non-corrosive fiber-reinforced polymers and their incorporation into concrete were part of an experimental program to lessen the impact of corrosion, which is one of the most important factors in the deterioration of concrete.15 different mix proportions were made and evaluated using equal amounts of cement, silica fume, extra fine materials, and water [10].
To reduce the salt content in sea sand and improve the construction of concrete goods, researchers have been conducting several studies.On the other hand, M-sand, which is widely used in concrete and has the same qualities as river sand because it is made by crushing rocks, is more expensive and eventually becomes unprofitable.Taking into account all the variables, it has been tried to show how effectively sea sand may be used as an alternative in full or partial replacement of river sand through this experimental investigation.In this study, the impact of sea sand on concrete's compressive strength was investigated.This study attempts to bring all of the efforts together and give a comprehensive explanation of how sea sand may be used effectively in concrete.It also displays the results of using sea sand in concrete.When sea sand was substituted for 20% of the river sand in concrete cubes during testing after 7, 14, and 28 days, the compressive strength increased from 39.676 N/mm2 to 44.908 N/mm2 [1].An accelerated test with a simulated marine environment was designed for the degradation of sea-sand concrete that was partially submerged in seawater.The mass, water absorption, and mechanical properties (compressive strength and dynamic modulus) were tested, and the impact of seawater on cement paste hydrates was thoroughly examined using a thermodynamic model [2].The compressive, split tensile, and flexural strengths of concrete made from sea sand are gathered from Thalikulam in the Thrissur district of Kerala at Snehatheeram beach or Love shore as a complete utilization of percent M-sand, percent sea sand, and partial utilization of M-sand and sea sand for fine aggregate [3].Because they are simpler to install and have a superior appearance and finish, concrete paving blocks make suitable materials for footpaths and roadways.
Paver blocks may easily be replaced when they break and need no maintenance industrial waste can take several shapes, some of which can be utilized in the construction industry to recycle waste and foster a greener environment [12].In order to determine the most affordable material that can replace fine aggregate in construction, the salt content of sea sand was removed using hot water and chemical treatment, and the performance of concrete was evaluated by utilizing sea sand as fine aggregate.The compressive strength of sea sand, which was substituted for fine aggregate in concrete after being treated with acetic acid, was then evaluated using the conductivity test.River sand was used in place of some of the sea sand in the fine aggregate as part of an experimental study of the strength characteristics of cement concrete.

Experimental program 2.1 Materials used 2.1.1 Cement
The cement used complies with IS: 8112:1989.It is Ordinary Portland Cement (OPC) of Grade 43.
The building industry's most used raw material is concrete.According to the Bureau of Indian Standards, concrete's assessment number reveals the minimal compressive quality that concrete must attain in just 28 days (BIS).When Portland cement and water are combined, chemical processes take place to release energy and result in the cement paste event, which allows the substance to solidify.
For OPC cement 43 grade, the concrete's minimum compressive quality at the end of the 28th day must be less than 43 Mpa or 430 kg/sq.cm.Numerous types of concrete can employ OPC 43.

Aggregates
The 10 mm coarse aggregate used complied with Table 2 of IS 383 and was used.The most fundamental components are coarse aggregates, which make up 70 to 75 percent of the volume in concrete formulations.Coarse particles are used in concrete, railroad ballast, and other purposes.It uses the gross total size, which is rated in accordance with IS 383:1970.The term "coarse totals" refers to particles larger than 4.75 mm.The typical measurement range for width is 9.5 to 37.5 mm.To achieve adequate toughness, the aggregate used in paver construction must be sound and free of brittle or honeycombed particles.The largest coarse totals utilized in the manufacture of paver blocks will be 12 mm.Because they are so heavy, aggregates have a significant impact on a structure's ability to 4 transfer loads.

Sea Sand
This sand is obtained from distant seabed excavations or ocean beaches.Similar to stream sand, ocean sand has finely tuned grains and a little deeper color.Sea sand from Zone II that complied with IS 38sieve had an IS sieve classification of 1.18mm was used.

Fly ash
Fly ash is the material that is used the most on the world (Class C). Fly ash was supplied by a ready-mix concrete factory located in Kivale, Pune (Maharashtra).If homogenous blending with cement is achieved, fly ash that complies with Grade 1 of IS 3812 (Part 1) can be used as a partial replacement for OPC.

Granulated Ground Blast Furnace (GGBS)
GGBS can be produced by drying and pressing molten iron slag from blast furnaces.It is one of the primary basic ingredients used to create a cement less binder with pozzolanic and cementitious characteristics.A blend of calcium, silicates, and alumina that contains around 90% GGBS satisfies the pozzolanic material criterion.If homogeneous blending with cement is accomplished, GGBS in accordance with IS 12089 may be used as a partial replacement for OPC cement.In the furnace, GBS is created.The intensity, hardness, and look of concrete are enhanced by the addition of CSH (calcium silicate hydrates) to ground-granulat ed slag from a burning furnace.GGBS was obtained from BG Shrike's Concrete Testing Lab located in Pune.

Superplasticizer
Suryotthan Melamine superplasticizer was utilized in this experiment to accelerate quick hardening and make free-floating concrete for precast applications.

Water
Water is frequently recognized as a crucial liquid component for all types of labor.In this investigation, drinking water is used for casting and curing.A paste is created when water and cement are combined, which holds all of the aggregate together.Due to the water-cement ratio (w/c %), water plays a crucial part in concrete.In this study, the w/c ratio was reduced to 0.45 in compliance with IS 456:2000.

.1 Slump Cone Test
As the project progresses, this test is carried out in the lab or on the construction site to ascertain the usefulness or consistency of a concrete mix.To ensure that the cement is constant throughout its development, it is done clump by clump.The slump value, which represents the water-to-concrete ratio, is used to gauge workability, or how readily concrete can be poured.On the other hand, various

Abrasion resistance test
Cast rubber molds in the form of Milano's were used to create the test specimens for the abrasion test.
To determine crushing, deterioration, and disintegration, the aggregate hardness and abrasion resistance of the 12 specimens are measured at 7, 14, and 28 days.The test specimens were manufactured in the same shape for each test.12 blocks were cast for each mix percentage, and they were assessed 7, 14, and 28 days later.

.4 Water absorption
After casting, the cubes were submerged in water for 28 days to cure.The paver blocks were then weighed, and the outcome was noted as the paver block's wet weight.The specimens were then uniformly bulked up by oven drying than at 1100 C before being weighed once more.Paver blocks must be able to absorb some water to effectively bond with mortar because they are not water resistant.
The initial rate of water absorption in milligrams is used to assess if pavers need to be wet before laying.

Casting and Curing of specimens
After the mix design was determined, the ingredients GGBS and Fly Ash were added in the ratios of 1:1, 1:1.2, and 1:1.3.Fly ash is used in percentages of 25 percent, 30 percent, and 40 percent.The GGBS proportion is held constant at 25%.Each component was completely dried before being mixed.
This dry mixture was then homogeneously mixed once more after the necessary quantity of superplasticizer of the suitable grade was added.This mixture was homogeneously blended once again after being given additional water and superplasticizer.The molds were filled with wet concrete, which was hand-compacted in three layers before being vibrated to achieve the desired level of 2.1.8. .

Carbonation test
The phenolphthalein indicator is sprayed on freshly exposed concrete that has been cracked away from the building or on split cores to conduct carbonation testing.A solution of the phenolphthalein indicator, which glows pink when in contact with alkaline concrete with pH values higher than 9, and goes colorless at lower pH levels, is used to measure the depth of carbonation. compaction.
Blocks made of Geopolymer that measure 250 x 120 x 80 mm.As required, these specimens were cast, and they were kept at room temperature for curing.After casting for a day, the specimens were removed from the mold.

Fig. 2. Weighing of
The casted specimens are demolded after the concrete haves completely hardened, typically after 24 hours.After being removed from the mold, the specimens are stored outside to cure.In the study, cure times of 7, 14, and 28 days were examined.After being cured, the specimens are checked for compression, abrasion, water absorption, and carbonation.

Compression Test Result
Table 3 presents the observation on the Compressive strength test for Geopolymer concrete paver blocks.The tested results of compression strength of paving blocks which are cured for 7, 28, and 56 days are tabulated in the table.

Water Absorption Test Results
Geopolymer concrete paver blocks' ability to absorb water is assessed after curing; elements affecting water absorption include the kinds of additives used, temperature, and exposure duration.
The data clarifies how the material performs in damp or humid conditions.According to IS 15658:2006, water absorption should be less than 7% after 24 hours.The results of the experiments are shown in Table 8, and Figure 9 displays the percentage of water absorption at various mix ratios.

Abrasion Resistance Test Results
The abrasion test was conducted both IS 15658:2006, which calls for rubbing a fast-moving ball race on the paver surface to leave a circular groove on the paving block.

Carbonation Test Results
Concrete is carbonated by phenolphthalein indicator on newly exposed concrete surfaces that have been torn away from the building or on split cores, which causes a gradual neutralization of the alkalinity induced by atmospheric carbon dioxide and Sulphur dioxide from the surface inwards.To evaluate the depth of carbonation, a phenolphthalein indicator solution is employed, which turns pink when in contact with alkaline concrete that has a pH higher than 9, and colorless when the pH is lower.2) Fly ash addition resulted in a rise in water absorption values of 5.67, 6.40, and 6.71 respectively.
3) The resistance to abrasion remained constant at 1875 mm3 per 5000 mm2 for replacement of sea sand.
4) Using Fly ash and GGBS instead of cement enables environmentally beneficial use as a paving unit while also lowering building expenses.
5) Ideally, sea sand-infused paver blocks will replace conventional concrete as the most widely used man-made material in the construction industry.
6) According to the findings, there was no carbonation present at any depths of 50 mm, 100 mm, or 150 mm, preventing the specimens from experiencing an increase in porosity brought on by the effects of carbonation.

Table 2
Mix proportions used for casting of paver blocks.

Table 4
Presence of carbonation

Table 8
Cost for Mix type III 25% GGBS+40% Fly ash for 12 blocks