Compressive and Tensile Strength of Concrete Using Lateritic Sand and River Sand as Fine Aggregate

Compressive and Tensile Strength of Concrete Using Lateritic Sand and River Sand as Fine Aggregate

Md Abdul Bari* , Md Ali Hassan* , Syed Aman ul Haq* , Prof Vaijanath Halhalli**

*Students, Department of Civil Engineering, P.D.A College of Engineering, Gulbarga, Karnataka State, India

**Associate Professor, Department of Civil Engineering, P.D.A. College of Engineering, Gulbarga, Karnataka State, India

Abstract–This paper is part of a study investigating the structural characteristics of concrete using various combinations of lateritic sand and river sand as replacement for conventional fine aggregate. Samples of concrete (eg. Cubes ,Cylinders) were made using varying contents of laterite and river sand as fine aggregate. The quantity of laterite was varied from 0% to 100%. The samples were cured for specified periods and tested in the laboratory for compressive strength. Workability tests were earlier carried out to determine the optimum water/cement ratios for three different water/cement ratios, namely. It was found that 0.48 water/cement ratio produced higher compressive strengths, Specifically compressive strength ranged from 32-37.932 N/mm2 for the mixes considered. These results compare favourably with those of conventional concrete. The concrete was found to be suitable for use as structural members for buildings and related structures, where laterite content did not exceed 60%.

Keywords: Laterite, river sand, workability, compressive strength, conventional concrete.

1. INTRODUCTION

   Currently India has taken a major initiative on developing the infrastructures such as express highways, power projects and industrial structures etc, to meet the requirements of globalization, in the construction of buildings and other structures concrete plays a vital role and a large quantum of concrete is being utilized. River sand, which is one of the constituents used in the production of conventional concrete, has become highly expensive and also scarce.in the backdrop of such a bleak atmosphere, there is a large demand for alternative materials.

   The environmental impact of concrete is a complex mixture of not entirely negative effects while concrete is a major contributor to green house gas emissions, recycling of concrete is increasingly common in structures that have reached the end of their life. Structures made of concrete have a long service life. As concrete has high thermal mass and very low permeability, it can make for energy efficient housing.

   Laterite is a pedogenic and highly weathered natural material formed by the concentration of hydrated oxides of iron and aluminium, further oxidized to form an insoluble precipitate of fine particles. Further concentration and dehydration and subsequent cementation forms hard concretionary nodules or the coalescence of particles into a hard vesicular mass of honeycomb structure where cavities may contain the host soil [2]. The soluble hydrated ferrous oxide (FeO) dissolves in water and is leached from parent rock together with aluminium oxide into a host soil. Further oxidation occurs to the ferrous oxide resulting in ferric oxide (Fe2O3), which is insoluble and precipitates into fine particles. Concentration of the oxides is either by residual accumulation or by solution, movement and chemical precipitation. Increased concentration due to loss of moisture results in the formation of discrete soft nodules of soil cemented with the precipitate. This process and the subsequent hardening of the nodules are referred to as concretionary development. The presence of oxides of iron and aluminium together with silica and kaolinite clay minerals in various different proportions gives laterite the distinct ochre, yellow, purple or red colour of which red is the most predominant emanating from the red iron oxide [2,6,8].

2. EXPERIMENTAL PROGRAM

The Objective of the project is to study the properties of concrete using lateritic sand as partial replacement to fine aggregate and also to compare the results between lateritic sand as fine aggregate with conventional river sand as fine aggregate.

1. Materials Used:

   1. Cement: Ordinary Portland Cement confirming to IS: 8112-1989 was used. Ultratech cement 53 grade procured from single source, properties of which are tested in laboratory are given in Table 1.

      Table 1:

      Sl. no	Character	Experimental results	As per Is:8112 1989
      1.	Consistency of cement	26%	–
      2.	Specific gravity	3.156	3.15
      3.	Initial setting time	50mins	>30min
      4.	Final setting time	230mins	<600min s
      5.	Compressive strength
      	3days	23.5N/mm2	>23
      	7days	35.8N/mm2	>33
      6.	Fineness of cement	1.2%	10%

   2. Basalt aggregate:

      In this present investigation aggregate available from local crusher was used. Size of the aggregate used was 20mm down size as one fraction and 12.5mm down size as another fraction of basalt coarse aggregate was used.

      Different tests such as specific gravity, fineness modulus, bulk density etc were carried out in the laboratory for basalt aggregate. The result are presented in Table.2, Table 3,Fig 1.

      Table 2. Physical properties of coarse aggregate.

      Sl.No.	Properties	Basalt aggregate
      1.	Shape of coarse aggregate	Angular
      2.	Specific gravity	2.89
      3.	Bulk density	1.65 g/cm3
      4.	Free surface moisture	Nil
      5.	Fineness modulus	7.06
      6.	Water absorption	1.667%

      Grading of coarse aggregate:

      Table 3: Sieve analysis results of basalt aggregate

      Sieve size (mm)	Cumulative % passing finer for Basalt aggregate
      40	100
      20	94.9
      12.5	64.3
      10	34.72
      4.75	0.04

      Cumulative % passing

      Sieve analysis test is carried out in the laboratory for the basalt aggregate and results are presented in Fig.1.

      120

      100

      80

      60

      40

      20

      0

      1

      Sieve size 1in0 mm

      Fig 1: Sieve analysis for Basalt aggregate.

   3. River sand:

      Good quality zone II fine aggregate was used. The various test results are shown in Table 3.

   4. Lateritic sand:

      Lateritic sand (4.75mm – 150µm size) of Humnabad was used in the present study for replacement of fine aggregate.

      Table 4: Physical properties of lateritic sand and river sand.

      Sl.No.	Properties	River sand	Lateritic sand
      1.	Specific gravity	2.74	2.73
      2.	Fineness modulus	3.137	4.43
      3.	Water absorption	2.5%	2.57%
      4.	Bulk density	1.43 gm/cm3	1.703 gm/cm3
      5.	Bulking	–	37.5%
      6.	Silt content	–	1%

      Grading of fine aggregates

      Table 5: Sieve analysis results of natural sand and Lateritic sand.

      Sieve size (mm)	Cumulative % finer for laterite	Cumulative % finer for sand
      4.75	99.50	97.303
      2.36	87.83	91.233
      1.18	44.10	81.116
      600µm	18.51	36.603
      300µm	4.73	6.590
      150µm	2.24	0.857
      Pan	0.004	0.014

      120

      100

      80

      60

      40

      lateritic sand

      river sand

      20

      0

      0.1

      seive siz1e in mm

      10

      cumulative % passing

      Fig 2: Sieve analysis for lateritic sand and river sand.

2. Workability test:

Concrete using lateritic sand and river sand as fine aggregates exhibit three basic forms of slump depending on the water/cement ratio just like normal concrete ( i.e True, Shear and Collapse ). This can be seen in the slump results shown in the table.7 below ( a to c ). The slump is between 0 and 120 mm.

slump (mm)

Workability tests are analyzed in the fig3. It can be seen that workability increases with corresponding increase in laterite content.

120

100

80

60

40

20

normal

concrete

laterized concrete

0

0.46 0.48 0.5 0.52 0.54

W/C ratio

Fig 3. Comparison of Slump Values For Different Water/Cement Ratios.

1. TRIAL CASTING

   Trial casting are carried out for the replaced concrete (fine aggregate by lateritic sand) and for conventional concrete for M25 grade of concrete using accelerated curing method and compressive strengths are tabulated in the Tables below. (Table 6 and Table 7).

   Table 6: Mix proportion for combination of lateritic sand and natural sand for M25 grade concrete.

   Sl.No	W/C	Cement	Fine Aggregate	Coarse aggregate
   1.	0.48	1	1.756	3.080
   2.	0.50	1	1.863	3.212
   3.	0.53	1	2.025	3.405

   Table-7: Workability Results

   Sl.No.	W/C Ratio	Slump (mm) Normal concrete	Slump (mm) Lateritized concrete
   1.	0.48	93	87
   2.	0.50	102	96
   3.	0.53	110	105

   Table 8: Trial casting results for for conventional concrete (i.e 0% replacement of F.A)

   Sl. No .	W/C	Slump value( mm)	Compressiv e strength (N/mm2)	Averag e value (N/mm2 )
   1.	0.48	93	30.876
   			31.748	31.510
   			31.094
   2.	0.50	102	24.336
   			25.426	24.620
   			24.099
   3.	0.53	110	28.696
   			27.824	28.042
   			27.606

   Table-9. Trial casting results for laterized concrete (i.e 50% replacement of F.A)

   Based on the results of trial castings presented in Table 5 and 6, it is observed that for M25 grade concrete W/C 0.48 with 50% conventional sand and 50% lateritic sand resulted in good workability and compressive strength. Therefore the mix proportion presented in Table 10 were finalized for further casting.

   Table-10. Mix proportion for combination of lateritic sand and conventional sand for M25 grade concrete.

   SL.N O	Grade of concret e	Cemen t	Fine aggregat e	Coarse aggregat e	W/ C
   1.	M25	1	1.756	3.080	0.48

   Total number of cubes cast for compressive strength test of size 150mm×150mm×150mm = 30.

   Total number of cylinders cast for split tensile test of size 150mm diameter and 300mm height = 15.

2. CASTING

   Cube specimen of 150mm×150mm×150mm were casted using the obtained mix proportion for compressive strength test. For split tensile test, cylinders of size 150mm diameter and 300mm height were cast as per IS standards. The moulds were filled in three layers and each layer is compacted by giving 25 blows with standard rod.

3. CURING

34

Compressive Strength (N/mm2)

33.5

33

32.5

32

31.5

31

30.5

30

29.5

29

0.46 0.48 0.5 0.52 0.54

Water/cement ratio

The cubes and cylinders were demoulded after 24 hours of casting. The cubes and cylinders were kept for curing under water immersion at 27±2°C. The specimens were

Fig 4: Relationship between compressive strength and water/cement ratio for Trial casting.

cured for 28 days.

1. TESTING

   1. Compressive strength

      At the end of curing period, i.e 28 days , the cube specimens were taken out of the tank and kept exposed to environment, till the surface becomes dry. The cube specimens were tested for compressive strength under compression testing machine and load was applied at the rate of 15 N/mm2 per minutes as specified by the code. Specimens were placed under in a direction perpendicular to the direction in which they were cast. The sample was wiped off from grit and placed centrally with load applied steadily to destruction and the highest load reached was determined. This is used to compute the compressive strength which is the ratio of highest load to the cross sectional area of the sample expressed in N/mm2. Six samples were used for each test and the average result was adopted as the compressive strength. The results of compressive strength for different percentage replacement are presented in the Table-11.

      Load setup

      Fig. Compressive strength Test setup

   2. Split tensile test

   At the end of curing period, i.e 28 days , the cube specimens were taken out of the tank and kept exposed to environment, till the surface becomes dry. The cylinders were tested under the compression testing machine for split tensile test as per Indian standard. The load was applied at the rate of 15 N/mm2 till the fracture occurs and the highest load reached was determined. This is used to compute the compressive strength.

   The tensile strength of concrete was obtained by subjecting cylinder to the action of compressive force .the test were carried out as per specifications of IS 58166-1970 on 2 number of cylinders. The specimen was placed between two patterns of compression testing machine .steel strip of 3mm thick, 12mm wide and 300mm wide were placed between the patterns and the surface of the cylinder. The load was applied at a uniform rate of 100 kn/minute till the specimen failed along the vertical diameter. The tensile strength of the concrete was calculated using the formula

   Split tensile strength = 2p/(dh).

   Three samples were used for each test and the average result was adopted as the tensile strength. The results of tensile strength for different percentage replacement are presented in the Table-12.

   Fig. Split Tensile Test

   SL.NO	Percentage of laterite replaced	Load in tons	Compressive strength in N/mm2	Average value
   1.	0%	64	27.904
   2.	0%	93	40.548
   3.	0%	70	30.520	35.320
   4.	0%	86	37.496
   5.	0%	89	38.804
   6.	0%	84	36.624
   7.	20%	72	31.392
   8.	20%	80	34.880
   9.	20%	66	28.776	32.627
   10.	20%	76	33.136
   11.	20%	83	36.188
   12	20%	72	31.392
   13.	60%	74	32.264
   14.	60%	99	43.164
   15.	60%	72	31.392	37.932
   16.	60%	93	40.548
   17.	60%	99	43.164
   18.	60%	85	37.060
   19.	80%	81	35.316
   20.	80%	77	33.572
   21.	80%	79	34.444	33.644
   22.	80%	80	34.880
   23.	80%	74	32.264
   24.	80%	72	31.392
   25.	100%	68	29.650
   26.	100%	75	32.700
   27.	100%	82	35.752	32.700
   28.	100%	93	40.548
   29.	100%	67	29.212
   30.	100%	65	28.340

   Table-11. Results of Compressive Strength Test. Table-12 : Results of split tensile test.

   SL. NO.	Percentage of laterite replaced	Load values in tons	Tensile strength in N/mm2	Average value N/mm2
   1.	0%	40	5.551
   2.	0%	37	5.135	4.95
   3.	0%	30	4.164
   4.	20%	26	3.608
   5.	20%	30	4.163	3.747
   6.	20%	25	3.469
   7.	60%	36	4.996
   8.	60%	24	3.330	4.163
   9.	60%	30	4.164
   10.	80%	20	2.776
   11.	80%	30	4.164	3.192
   12.	80%	19	2.637
   13.	100%	24	3.330
   14.	100%	20	2.775	3.052
   15.	100%	22	3.053

2. RESULTS AND DISCUSSION

   1. Discussion Of Compressive Strength Results:

      Fig 5. indicates the relation between compressive strength v/s percentage of lateritic sand added in the concrete for M25 grade concrete. From the fig it is clear that the concrete containing the lateritic sand of about 20%, 80% and 100% have resulted in nearly the same strength i.e 32.627 N/mm2,33.644N/mm2 and 32.700N/mm2 respectively. However concrete prepared with lateritic sand 60% has resulted in

      higher strength (37.932N/mm2).

      39

      38

      37

      36

      35

      34

      33

      32

      0

      50

      100

      150

      % Of Lateritic Sand

      Compressive Strength (N/mm2)

      Fig 5: Comparison of Average values of Compressive Strength for Different percentages of Laterite Content in Concrete.

   2. Discussion Of Splitting Tensile Strength Results:

      Split Tensile Strength (N/mm2)

      Fig. 6. Indicates the relationship between compressive strength v/s percentage of lateritic sand added in the concrete of M25 grade. From the fig it is clear that concrete prepared with laterite content of 80% and 100% have resulted in nearly the same strength i.e. 3.92N/mm2 and 3.052 N/mm2 respectively. The concrete prepared with laterite content of 20% shows a slightly higher strength compared to the above two percentages. However the concrete with laterite content of 60% has resulted in higher strength (i.e 4.163N/mm2) compared to all above percentages of laterite content.

      4.5

      4

      3.5

      3

      2.5

      2

      1.5

      1

      0.5

      0

      0

      50

      100

      150

      % Of Lateritic Sand

      Fig 6: Comparison of Tensile Strength for Different percentage of Laterite Content in Concrete.

3. CONCLUSION

1. The compressive strength and also the split tensile strength increases as the percentage of lateritic sand increases upto 60% and then it starts decreasing if the percentage of laterite increased above 60%. Therefore 60% replacement of river sand by lateritic sand can be used effectively for better results.

2. The 80% and 100% replacements almost gives the same strengths as that of the normal concrete.

3. Therefore 60%,80% and 100% replacements levels can used effectively resulting in good results and workability.

4. The manually sieved lateritic sand can used for the preparation of concrete as it is available freely in abundant quantity and it is also economical.

5. Using lateritic sand as a fine aggregate replacement material in the preparation of concrete makes the mix cohesive and workable.

6. M25 grade of the concrete can be prepared easily with good workability without requiring the super plasticizer.

7. The locally available lateritic sand as replacement to river sand in the preparation of the concrete results in good economy.

8. By using this material as fine aggregate we can reduce the demand of the conventional sand in the preparation of the concrete.

REFERENCES

1. Adepegba, D. (1975) A comparative study of normal concrete with concretewhich contain laterite instead of sand. Building science, 10(2), pp. 443-552

2. Aleva, G.J.J.; (1994) Laterites. Concepts, Geology, Morphology and Chemistry. 169 pp. ISRIC, Wageningen, The Netherlands, ISBN 90-6672- 053-0.

3. Ata, O., Olusola, K. O. and Aina, O. O. (2005) Factors affecting Poissons ratio of laterized concrete. Jurnal Sains Dan Teknologi, EMAS, Jakarta, 15(2), pp. 77-84.

4. Balogun, L, A (1982) The use of lateritic soils in structural concrete. Proceedings 1st National conference; Nigerian geotechnical association, Lagos,Nigeria, 1982.

5. Balogun, L, A. and Adepegba, D. (1982) Effect of varying sand content in laterized concrete. International journal of cement composites and lightweight concrere, 4(4), 1982, pp.235-241.

6. Bardossy, G. and Aleva, G.J.J. (1990) Lateritic Bauxites. 624 pp. Developments in Economic Geology 27, ELSEVIER, ISBN 0- 444-98811-4.

7. Osunade, J. A. (1994) Effect of grain size ranges of laterite fine aggregate on the shear and tensile strengths of laterized concrete. International journal for housing science and its applications, 4(1) pp. 8-15.

8. IS 2386 Indian Standard (1963): Method of test for aggregate.

9. IS 12062 Indian standard (2009): Method of concrete mix design.

10. IS 9013 Indian standard 1978: method test for compressive strength.