Study of Granulated Blast Furnace Slag as an Alternative to River Sand and Manufactured Sand as Fine Aggregate in Concrete
Ch.Srinivasarao¹, M. Kameswararao²
1Research Scholar, Dept. of Civil Engineering, K L University, Guntur (Dt), AP, India.
2Professor, Dept. of Civil Engineering, Malla Reddy College of Engineering, Hyderabad, India.
Abstract-The present challenge in front of Civil Engineers is to find alternative materials for fine aggregates in concrete. Since, most of the state Govt. banned the dredging of River sand. To maintain a balance between the environmental problems and Construction industry, it is necessary to find out the alternative materials for fine aggregates to be used in concrete. In this connection, Granulated Blast Furnace Slag was considered as a fine aggregate in concrete. At present, in India steel Industry produces about 40 Million Tonnes. By 2020 it is estimated as 60 million tonnes. The Author has investigated the effect of compressive strength of concrete, when Granulated blast furnace slag was used as a fine aggregate in concrete. This work includes the partially and fully replacement of river sand by granulated slag in M25 Grade of concrete with a constant 0.45 W/C ratio. Slag replacement of 50, 80, 100% are used. It has been observed that concrete made with 50% of river sand and 50 % Granulated blast furnace Slag (GBFS) shown Best results comparatively with 100% replacement.
Keywords – GBFS, Granulated Blast Furnace Slag, River Sand, Manufactured Sand, Concrete
I. INTRODUCTION
The Concrete Industry is the largest consumer of natural resources like, sand, gravel, crushed rock, etc. Sand &
crushed stone requirement is about to the tune of 10 billion tonnes per annum .Natural sand obtained from river bed is getting depleted and due to indiscriminate dredging, most of the State Govt.’s imposed a ban on mining of river sand. Environmental restrictions for dredging of sand from riverbeds have resulted in a search for alternative source.
The challenge for the government is to reduce the industrial by products which impacts to both health and environment when not disposed properly [1]. Granulated slag, steel chips are industrial by products in the Iron and steel industry and causes a nuisance. Increase in population which causes an acute shortage of building Materials and the civil Engineers have been challenged to convert the Industrial by products to useful Building and Construction materials [2]. Thus, the manufactured fine aggregates and Granulated Blast Furnace Slag appear as an attractive alternative to natural fine aggregates for cement mortars and concrete. Slag is a non-metallic inert by product of steel industry primarily consists of silicates, Alumino silicates, and calcium-alumina silicates. The choice of aggregates is important and their quality plays a key role; they can not only limit the strength of concrete but their characteristics, they effect the durability and performance of concrete[3].
The inherent benefits of slag play critical part in the preservation of natural resources whilst delivering premium performance. The inherent benefits of slag play critical part in the preservation of natural resources and performance. Hence, it could be recommended that Granulated Blast Furnace Slag(GBFS) could be effectively utilized as fine aggregate in masonry, plastering and all concrete applications. Studies show that, the Natural sand can be replaced by Granulated slag as a fine aggregate in concrete [4-6].
A. Granulated Blast Furnace Slag (GBFS)
Granulated Slag is being produced during the process of manufacturing the pig Iron in Blast furnace at around 1400° to 1500°C in the molten form. The granulated slag is obtained by rapidly chilling (Quenching) the molten ash from the furnace by means of water or steam and air and it consisting essentially of glass containing silicates and Alumina Silicates of lime.FIG.1 Samples of GBFS, Natural sand, Manufactured sand.
II. OBJECTIVES AND METHODOLOGY OF THE STUDY
The Primary objective of the investigation is to study the suitability of GBFS as per IS:383 and the development of the compressive strength of concrete made with GBFS as a fine aggregate in M25 Grade of concrete in severe condition.
1. Conducting of Sieve Analysis of River Sand, Manufactured Sand and Granulated Slag,
2. The development of the compressive strength of concrete made with Granulated slag as a fine aggregate (GBFS) in M25 Grade of concrete in severe condition. The author tested the concrete cubes with Ordinary Portland cement and with Portland Pozzolana Cement (PPC) for 3 days, 7days and 28 Days compressive strength. The concrete cubes were casted with 100% river sand as a reference and replacement of river sand by 50%, 80% and 100% by GBFS for observation. Slump is also noted at all replacement levels. Finally, based on analysis and discussions of the test results, conclusions are drawn.
III. EXPERIMENTAL RESULTS
Conducting of Sieve Analysis of River Sand, Manufactured Sand and Granulated Blast Furnace Slag (GBFS).
A. Sieve Analysis:
Sample of 3 kg of fine aggregate brought to an air-dry condition before weighing and sieving by means of heating at a temp. of 1000C the air- dry sample is weighed and sieved successively on the sieves starting with largest i.e.
4.75mm, 2.36mm, 1.18mm, 600mic, 300mic, 150mic.
Each sieve had been shaken separately over a clean tray on completion of sieving; the material retained on each sieve with the material cleaned from the mesh had been weighed. The cumulative weight passing each sieve had been calculated as a percentage of the total sample weight.
The results were compared with the limits given are IS: 383 for different zones such as Zone-I, II, III & IV and accordingly, the results were tabulated as per the limitations.
TABLE 3.1:PHYSICAL PROPERTIES OF RIVER SAND,MANUFACTURED SAND AND GRANULATED SLAG
S. No Description River Sand Manufactured Sand Granulated Slag Relevant IS code
1 Specific Gravity 2.8 2.6 2.8 IS: 2386, Part-III
2 Bulk Density Kg/m3 1603 1850 1220 IS: 2386, Part-III
3 Moisture Content (%) 0.8 1.5 1.0 IS: 2386, Part-III
4 Water absorption (%) 0.6 2.6 1.0 IS: 2386, Part-III
IS: 2386, Part-IV
5 Fineness Modulus 2.87 2.67 2.86 IS: 2386 Part- I
6 Fines through 75 µ , % 0.65 6.0 0.5 IS: 383
TABLE 3.2:SIEVE ANALYSIS OF RIVER SAND,MANUFACTURED SAND AND GRANULATED SLAG
IS Sieve River sand
% Passing
Manufactured Sand% Passing
Granulated Slag
% Passing
% Age passing for single sized aggregates of Normal Sand
(IS 383 - 1970) Zone II
4.75mm 99.42 100 99.50 90 to 100
2.36mm 94.74 90.70 94.75 75 to 100
1.18mm 68.35 66.20 70.20 55 to 90
600Microns 41.40 39.80 39.70 35 to 59
300 Microns 6.90 25.5 7.00 08 to 30
150 Microns 1.75 9.90 1.95 0 to 10
TABLE 3.3:PHYSICAL PROPERTIES OF X(OPC53GR.) AND Y(PPC)CEMENT
Cement Sp.Gravity IST
(Minutes)
FST (Minutes)
Compressive strength MPa. Fineness Sq.M/Kg.
3 Days 7 Days 28 Days OPC 53Gr. (X)
(IS:269- 2015) 3.15 145 240 42 52 63 311.9
PPC (Y) –
IS:1489 part-I 2.91 166 260 25 33 57 346.40
Fig 3.1: Sieve Analysis
TABLE:3.4COARSE AGGREGATE AND GBFS AS A FINE AGGREGATE (TESTED AS PER IS2386):
IS Sieve Size, mm
Cumulative percentage of material passing Fine Aggregate (GBS) Coarse Aggregate
20 – 10 mm < 10 mm
40 100 100 100
20 100 99.09 100
10 100 4.62 98.46
4.75 99.50 3.03 12.88
2.36 94.75 0 0
1.18 70.20 0 0
0.6 39.70 0 0
0.3 7.0 0 0
0.15 1.95 0 0
Fine Aggregate (GBFS) conforming to Zone –II to meet IS 383 specification for combined grading of coarse aggregate, the following proportions of different sizes were used. Coarse aggregate (20mm) = 60%, and Coarse aggregate (<12.5mm) = 40%
TABLE:3.5CHEM.ADMIXTURE:MID PCEECMAS92SP IS Sieve Size, mm Cumulative percentage of material passing Combined
Grading
Limits as per IS:383 20mm (60%) <12.5mm (40%)
40 60 40 100 100
20 59.45 40 99.45 95 - 100
10 2.77 39.38 42.15 25 - 55
4.75 1.82 5.15 6.97 0 - 10
IV. DESIGNMIXFORM25ASPERIS10262-2009 TABLE:4.1
Cement Kg/Cub.M
River sand Per Kg/Cub.M
Coarse Aggregate Per Cub.M Total Water Lit. (0.45w/c)
Chemical Ad.
Mix Lit.
20mm 12.5mm
372.40 660 699.60 572.40 172.70 1.7
TABLE 4.2COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH OPC AND 100% RIVER SAND
Sample No: 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 1A 38.8 44.0 52.3 130mm
Cube 1B 40.0 43.8 51.9
Cube 1C 39.0 42.6 50.7
Avg. 39.2 43.5 51.6
0 20 40 60 80 100 120
River Sand
Manufactur ed Sand Granulated Slag
Sieve size in mm
Percentage passing through
TABLE 4.2COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH OPC AND 100% RIVER SAND
Sample No: 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 1A 38.8 44.0 52.3 130mm
Cube 1B 40.0 43.8 51.9
Cube 1C 39.0 42.6 50.7
Avg. 39.2 43.5 51.6
TABLE 4.3COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH OPC AND 50%GBFS Sample No: 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 2A 36.6 42.0 49.8 110
Cube 2B 38.3 41.3 48.6
Cube 2C 37.2 40.8 50.1
Avg. 37.3 41.3 49.5
TABLE 4.4COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH OPC AND 80%GBFS Sample No 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 3A 34.0 38.02 45.0 70
Cube 3B 33.8 38.6 45.8
Cube 3C 31.2 40.1 43.0
Avg. 33.0 38.8 44.6
TABLE 4.5COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH OPC AND 100%GBFS Sample No 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 4A 30.2 31.0 40.1 45
Cube 4B 29.8 32.8 40.8
Cube 4C 29.0 34.3 38.6
Avg. 29.60 32.36 39.80
TABLE 4.6COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH PPC AND 100%RIVER SAND
Sample No 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 1P 28.6 38.0 48.9 145
Cube 1P 27.3 37.4 50.0
Cube 1P 26.2 38.2 48.2
Avg. 27.3 37.8 49.0
TABLE 4.7 COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH PPC AND 50%GBFS Sample No 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 2P 26.8 37.1 47.2 120
Cube 2P 27.2 36.8 46.8
Cube 2P 26.0 35.4 46.2
Avg. 26.6 36.4 46.7
TABLE 4.8COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH PPC AND 80%GBFS Sample No: 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 3P 22.8 29.9 38.6 75
Cube 3P 21.6 28.2 39.2
Cube 3P 23.1 30.1 40.8
Avg. 22.56 29.4 39.53
TABLE 4.9COMPRESSIVE STRENGTH (MPA) OF CONCRETE CUBES WITH PPC AND 100%GBFS Sample No: 3 Days (Mpa) 7 Days (Mpa) 28 Days (Mpa) Slump (mm) @1 hr
Cube 4P 20.1 25.6 31.3 50
Cube 4P 19.4 23.4 30.1
Cube 4P 20.8 26.2 32.4
Avg. 19.9 25.0 31.2
V. RESULTS AND DISCUSSIONS
As per the above Physical analysis the GBFS can be used as fine aggregate in concrete and mortar as a replacement of natural sand, since, it meets IS:383-1980 and satisfy Zone:II.
In OPC and PPC concrete, the natural river sand was replaced by Granulated blast furnace slag at 50, 80 and 100%. The compressive strength of concrete made with OPC with 100% natural river sand as a reference and compared with the replacement of natural sand by 50% , 80% and 100%GBFS. Concrete cube with 100% got 51.60Mpa at 28 days when, natural sand was replaced by 50% the compressive strength achieved at 49.5Mpa. At 80
% and 100% replacement levels, the compressive strength achieved at 44.6 and 39.8 The concrete made with PPC with 100% natural sand got the compressive strength of 49.0Mpa at 28 days and 46.7MPa, 39.5Mpa and 31.2 Mpa at replacement of natural river sand by GBFS by 50, 80 &100% respectively.
The workability also noted for concrete made with OPC and PPC with 100%natural sand given at 130mm and 145mm respectively. The slump measured at replacement of natural sand by GBFS at 50, 80 and 100% were 110, 70, 45mm and 120, 75 and 55mm respectively. Based on the test results, we have observed that the GBFS percentage is increased towards 100% in concrete, there a decrease in compressive strength as well as workability in OPC and PPC concrete.
VI. CONCLUSION
It is recommended that 50% natural sand can be replaced by GBFS to get the optimum compressive strength and workability as compared with 100% natural river sand concrete made with OPC and PPC.
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