ABSTRACT :- This research work is done in case to investigate the use of the hypo sludge with molasses and cement, so that stabilized blocks of red mud can be prepared. The lab tests have given the results which show that the mechanical plus the physical properties of the red soil were assessed. The unconfined compressive strength, modulus of rupture, Ultrasonic Pulse Velocity (UPV) and water absorption tests were performed for this soil with and without hypo sludge, cement and molasses. This has been identified that the use of the 20 percent of hypo sludge with the cement and the molasses as the additives in the soil provides the optimum stabilization to the soil and this work is proven through the process of the unconfined compression test. The results have concluded that the hypo sludge can be effectively used in the red soil as a stabilizer for the preparation of the mud blocks.
SAMPLE PREPARATION AND TESTING
Properties of Soil
To find out the properties of soil and the effective use of stabilizer, various laboratory test where carried out and its Atturberg limits were found. In the present work the soil is improved by adding industrial wastes in different percentage. The effect of addition of industrial wastes on the strength behavior of the soil is studied by varying percentage of industrial waste by weight of sample7.
Casting of Stabilized Mud Blocks
The soil samples were prepared as two sets of six different mix proportions by varying the percentage of hypo sludge along with 5% of cement and molasses as constant. The mix proportions are designated and are given in the Table 5 and the casted mud blocks are shown in Figure 4.
It is to determine the optimum percentage of hypo sludge is required with cement and molasses for the manufacture of stabilized mud blocks. Initially, soil samples were thoroughly mixed with hypo-sludge at dry state.
Then it was again mixed with water at optimum content, cement and molasses. The mixing should be thorough and formations of lumps have to be avoided so as to prevent the blocks from the formation of voids during cast. AURAM as one of the manual pressing equipment to cast stabilized mud blocks. Casting of blocks was carried out through compression of mud. The author was used for casting of mud blocks which can cast two blocks at a time. The required proportion is mixed and the mud is loaded in the mould and was pressed to stabilized mud blocks. The size of the bricks casted is 230 mm length, 230 mm width, 90 mm thick.
Unconfined Compressive Strength Test
It is the load per unit area at which an unconfined cylindrical specimen of soil will fail in the axial compression test. It has been done based on IS 2720 (Part 10): 1991 Indian Standard. This is a quick and simple testing to determine the compressive strength. The sample specimens were prepared at its maximum dry density and optimum moisture content. The specimen for the test shall have a minimum diameter of 38 mm and the height to diameter ratio shall be within 2 and 2.5 as per IS Codal provision. The Measurements of height and diameter shall be made with Vernier calipers or any other suitable measuring device to the nearest 0.1 mm8.
Compression Strength Test
The blocks are prepared and cured for 28 days by covering it with a polythene sheet and water was sprinkled to maintain the humidity. The blocks were then taken and dried about one hour before testing. The blocks made with HSC and HSM mix proportions were tested at 7th, 14th, 21st and 28th day of curing. The blocks were tested in Compression Testing machine. The test was conducted and the following are the average compressive strength obtained on the testing which is shown in the Figure 6a and 6b.
Ultrasonic Pulse Velocity Test (UPV)
This test was done based on IS 13311 (Part 1): 1992. The Ultrasonic Pulse Velocity is one of the widely used common non-destructive testing techniques in research and construction industry. The pulse or stress wave velocity in a material is related to Young’s modulus of elasticity, density and Poisson’s ratio9.The ultrasonic pulse is generated by an electro acoustical transducer which is less than 20 kHz. When the pulse is induced on an object from a transducer, a complex system of stress waves is developed which includes longitudinal (compression), shear (transverse) and surface (Rayleigh) waves. The quality of object will be assessed based on the velocities of waves obtained. Higher the velocity the object is good in homogeneity and uniformity, lower the velocity there may be presence of cracks, voids or flaws inside the object which make the path length longer10.
Modulus of Rupture (Flexural Strength)
This test was conducted based on IS 4332 (Part VI): 1972. Flexural strength also known as Modulus of rupture is the limit at which a material can withstand flexural stress. When an object is subjected to flexural stress, it undergoes both tension and compression because of bending moment. Flexural strength of a material will depend on either its tensile strength or compressive strength, whichever is lesser. This standard covers the procedure for determining the flexural strength of soil cement by the use of a simple beam with third point loading11.
Water Absorption Test
The blocks were tested in accordance with the procedure laid down in IS: 3495 (Part II) 1976, after immersion in cold water for 24 hours, as per the code the average water absorption shall not be more than 15% by its weight12.
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