Experimental study on concrete by partial replacement of fine aggregate with steel slag and cement with metakaolin and glass powder

The present study will describe the characteristics and the effects of concrete properties when fine aggregate is partially substituted by steel slag and cement partially substituted by metakaolin and glass powder at 0%, 10%, 20% and 30. Compressive, tensile, flexural strength, and durability tests were conducted on the cube and cylinder specimens. The test results were compared with conventional concrete specimens. The tests are conducted on specimens for 7days and 28days. Based on the outcomes of the study, it was concluded that replacing cement and fine aggregate with glass powder, metakaolin, and steel slag increases the strength of concrete and reduces attack at 30% replacement. Hopefully, the results have clearly demonstrated the concrete constructions can also be made from eco-friendly alternative materials which are cost-effective and sustainable for longtime.


Introduction
The world uses a great deal of concrete for construction.Water, fine aggregate, and cement are all mixed to create the mix.In the present day, the construction industry is growing rapidly and requires an enormous amount of Concrete [3].The demand for concrete leads to greater utilization of cement and aggregates [5].As we know, cement has outstanding binding properties, but the manufacturing of cement leads to greater emission of CO 2 [7] .Also, the increasing demand for fine aggregates/natural sand and becoming more expensive which leads to the reduction of natural resources [1].To reduce those risks, some of the alternative materials are introduced in the construction industry.Some of the alternative materials are steel slag, metakaolin and glass powder, rice husk.The present study utilizes some of alternative materials like steel slag, metakaolin, and glass powder as partial replacements with different percentage replacements to make concrete[2]. .

Research significance
Most researchers have conducted tests on concrete with one or two alternative materials added as partial replacements [6].However, this study aims to make concrete specimens with three alternative materials, Cement can be substituted partially with metakaolin, glass powder, and fine aggregate can be substituted partially with steel slag [4].

Materials
A concrete mix is made up of fine aggregates, coarse aggregates, cement, and water.In the present study, concrete is prepared with Metakaolin and glass powder are used to replace part of the fine aggregate and cement with steel slag.x Coarse aggregate is an aggregate particle which retain on a 4.75mm sieve is called as.It is a larger size particle.A coarse aggregate of 12.5mm is used in the present study.• Fine aggregate is an aggregate particle which passes through a 4.75mm sieve is called as fine aggregate.It is smaller in size • Metakaolin is a high quality pozzolanic material.It is made by calcining kaolin clay at a temperature between 650°C to 850°C.• Glass powder is a powder made from waste ground glass.When the particle size of glass is less than 75m, it is amorphous and may be pozzolanic.Because of its silica content, ground glass is considered a pozzolanic material and as such exhibit's properties like other pozzolanic materials.
• Steel slag is a by-product of steel.When impurities are separated from molten metal, it is formed.
Slag as an alternative material for concrete reduces the need for natural rock, thus reduces the preserving our natural rock resources.

Methodology
Literature review is studied in the first phase of research.Identifying the gap by analyzing the literature reviews.Then objectives are taken from the gap of literature review.Next is to find the materials and collect them from the source/ locally available store.After that, materials properties are noted.Then, mixing of materials are done by selecting proper grading of materials and mix them as per proportions.First Conventional Concrete is made without any percentage of replacement.Then alternative materials like steel slag, metakaolin and glass powder are added in percentage wise of 10%, 20% and 30% and then mix is made as per Mix design of M30 Grade.For both concrete mixes cubes and cylinders were cast.Then, all type of specimens which are cast were placed in water tank for curing for 7days and 28 days.For 7 th day, specimens were removed from tank and compressive, tensile, and flexural test was performed.Same tests are applied for 28 th day of curing.Durability tests like acid attack and alkali attack test were also conducted.

Tests
Various tests are conducted on concrete specimens made with alternative materials like steel slag, glass powder and metakaolin along with ordinary concrete specimens.

Compression strength test
The specimen is compressed and deformed at various loads is recorded.Compression Test is conducted using standard Compression Testing Machine.
F=P/A where, F is Compressive strength kn/m 2 , P is the force applied to the sample in kn, and area of the sample(A) in m 2 .

Tensile strength test
Effect of alternative materials on tensile strength of hardened concrete with alternative resources is proposed to be studied at 7 days and 28 days by conducting a tensile test determines the behaviour of materials under crushing loads.The maximum load applied to the specimen when first crack appears is then noted.

Flexural strength test
Specimens were kept in water for 7 and 28 days for curing, and then tested in dry condition.
F=PL/bd 2 Where, F is flexural strength in kn/m 2 , applied load(P) on the sample in KN, Length(L) in meters, Breadth(b) in meters, and Diameter(d) in meters.

Durability test
Effect of alternative materials on durability properties of hardened concrete with alternative resources is proposed to be studied at 28 days by conducting an alkali and acid attack test determines the behavior of materials.The present study uses H 2 SO 4 and NaOH as acid and alkali, respectively.An alkali attack test was conducted by immersing specimens in 4% of NaOH solution.

Result and discussion
Test results are obtained by testing the specimens with UTM in accordance with IS: 516 -1959. 1282 (2023)   Based on the above test results, we can conclude that the split tensile Strength of the alternative materials Mix concrete is increasing from 3.4N/mm 2 for MGS 0 to 5.5N/mm 2 for MGS 30 after seven days.The strength is slightly increased from 4.2N/mm 2 for MGS 0 to 5.91N/mm 2 for MGS 30 at 28 days The Flexural strength of the alternative materials Mix concrete is increasing from 2.4N/mm 2 for MGS 0 to 2.5N/mm 2 for MGS 30 after seven days.The strength is slightly increased from 3.5N/mm 2 for MGS 0 to 3.6N/mm 2 for MGS 30 at 28 days.The durability test of the alternative materials mix concrete, shows the acid and alkali attack test gives minimum attack at 30% replacement.

Conclusion
The results obtained from the tests concluded the following • By increasing the percentage of MGS, there is an increasing in the strengths of concrete.But for compression strength at 10% replacement of MGS, there is slight decrease in strength compared to conventional concrete strength.
• The optimum replacement percentage of Cement containing slag and fine aggregates containing metakaolin and glass powder is at 20%.
• Concrete durability properties are less affected by alternative materials at 30% replacement.

Graph 1: 7 days & 28 days compressive strength
Based on the above test results, we can conclude that the compressive Strength of the alternative materials Mix concrete is increasing from 35.11N/mm 2 for MGS 0 to 37.54N/mm 2 for MGS 30 within seven days.The strength is slightly increased from 38.03N/mm 2 for MGS 0 to 39.23N/mm 2 for MGS 30 at 28 days.However, the compressive strength results for different Mixes show higher values than MGS 0