Experimental Investigation on Concrete with Replacement of Fine Aggregate by Lathe Waste

Concrete being the most important and widely used material is called upon to possess very high strength and sufficient workability properties. Today the construction industry is in need of finding cost effective materials for increasing the strength of concrete structures. Hence, there is a need to identify and use of materials that reduce use of natural resources and increase use of waste products. Great quantities of steel waste fibers are generated from industries related to lathe. Therefore, an attempt has been made in the present investigation to study the influence of addition of waste material like lathe waste as a replacement to fine aggregate. In the present experimental investigation, an attempt will be made to analyze the mechanical characteristics of the waste Steel Scrap material which is available from the lathe machine is used as a Lathe waste in cement concrete for various construction works and to optimize fibre content. The outcome of this project shall be useful for various industries and workshop generating steel scrap from lathe machine.


B. Fine Aggregate
The material which is passed through 4.75mm IS sieve is termed as Fine Aggregate. Usually natural river sand conforming zone II was used as fine aggregate. The specific gravity of fine aggregate is 2.63.

D. Lathe Waste
Lathe scarps are the waste materials which are collected from workshops and other steel industries. They are similar to the steel fiber but they don't have any regular shape and size. These scraps in the powder form which is used as a reinforcing material in concrete to enhance the various properties of concrete.

III. MIX PROPORTIONS FOR CONCRETE
The concrete used for the study is of M25 grade. The mix design is carried out as per the guidelines of IS 10262 (2009). The mix proportions of the concrete were 1:1.4:2.8:0.5 (Cement:Fine Aggregate:Coarse Aggregate:Water-Cement ratio). Lathe waste in the order of 2%, 4%, 6% and 8% is used in concrete as a replacement of fine aggregate. The mixing can be done manually.
IV. RESULTS AND DISCUSSIONS The compressive strength test and split-tensile strength tests were conducted on prepared concrete specimens. The specimens were cured for 7 days and 28 days before testing. The results have been tabulated in the tables below.
A. Compressive Strength Test: The compressive strength test has been conducted for conventional concrete (i.e., 0% replacement) and fine aggregate replaced by lathe waste. The fine aggregate is replaced by 2%, 4%, 6% and 8%. The test results of 7 days and 28 days are shown in table IV and figure 2.   The above graph indicates that the compressive strength of 28 days with various percent of lathe waste added to concrete in replacement to fine aggregate (sand). The optimum strength gained after 28 days curing period is at 2% addition and lowest at 8% addition of lathe waste in replacement to fine aggregate. It is found that in replacement of 2% of lathe waste at 7 days, there was 9% increment in compressive strength when compared to conventional concrete. Whereas in the replacement of 2% at 28 days, there was an increment of 18.80 % in compressive strength as compared to conventional concrete. When we observe the results of 4% replacement is higher than that of the conventional concrete. So, in order to minimise the waste generated, we can use replacements up to 4% n the execution.

B. Split-Tensile Strength Test:
The split-tensile strength test has been conducted for conventional concrete (i.e., 0% replacement) and fine aggregate replaced by lathe waste. The fine aggregate is replaced by 2%, 4%, 6% and 8%. The test results of 7 days and 28 days are shown in table V and figure 3.  It was found that the replacement of lathe waste in concrete increases the split tensile strength of concrete cylinder. For 0%, 2% and 4% of lathe waste content by weight of fine aggregate in concrete, the tensile strength obtained was 2.48, 2.85, and 2.34MPa respectively for 7 days. This indicates there is 13% of increment in splittensile strength when compared to conventional concrete. Whereas in the case of 28 days, for the replacement of 0%, 2% & 4% obtained was 2.86, 3.25 and 2.96MPa respectively. There is 12% increment for 2% when compared to conventional concrete. We can see that 4% replacement of fine aggregate is also giving better result when compared to conventional concrete. So, we can use replacements up to 4% so that the utilisation of waste material can be increased.
V. CONCLUSION This investigation shows that replacement of lathe waste improves mechanical properties of concrete. Various tests were done at 7 and 28 days after casting the specimens. The following conclusions were made from the test results and discussions of this investigation:  When the fine aggregate was replaced with 2% of lathe waste, there was an increase of 18.8% in compressive strength test result. When fine aggregate is replaced with 4% of lathe waste, the increment in compressive strength test was 11% compared to conventional concrete, which indicated that the use of 4% replacement is also possible in order to maximise the waste utilisation.  It was found that for 2% replacement, there will be 13% of increment in split tensile strength after 7days and 12% after 28days. For 4% replacement, better result is obtained compared to conventional concrete.  Natural resources are not unlimited and also, there is a global need to protect to our environment and preserve our scarce natural resources for next generation.  Use of lathe waste in concrete is beneficial as compared to conventional concrete reduces the environmental pollution as well as providing economical value for the waste material.