Enhancement of Strength Characteristics of Poorly Graded Soil by Flyash a

Fly Ash is the waste material, which is obtained af ter burning coal in Thermal Power Plants. It can be use d as a stabilizer for soil due to its pozzolanic e an inherent selfhardening property under favourable conditions of moisture and compaction. This project aims at increasing the strength of poorly graded so ils by using Fly Ash and cement as admixtures. Some percentage of Fly Ash without any addit utilized so as to reduce the cost of construction a nd this is a good method for disposal of it. Fly Ash w as added in various percentages like 10, 20, 30 and 40 percentages (% by volume). Initially all basic Geotechnical properties of the soil such limit, plastic limit, shrinkage limit, Grain Size Analysis, Specific Gravity, Free Swell Index, Unconfined Compressive Strength, OMC and MDD were determined. Later on the stabilized mixes were tested for CBR (California Bearing Ratio) which is a indirect measurement of strength. After the detaile d experimental investigation it is observed that 30% addition of Fly Ash has shown maximum strengths, so that to obtain much more strengths cement was added in 2, 5, 8 and 10 percentages to this optimum Fly Ash with soil. After that the soil mixes were tested for CBR (California Bearing Ratio) to check it’s feasibility in Flexible Pavement constructions . The strengths were checked in both Unsoaked and soaked conditions and at various curing periods and 28 Days. Among all proportions 30% Fly Ash+8 % of the cement has shown maximum strengths, so that it was decided as optimum mix. Maximum strengths were obtained at 28 days curing period fo r all proportions of mixes so that this period is dec i as optimum curing period. Eventually this project work facilitates an economical, strong and durable construction material for Flexible Pavements. Scientific Research and Development | www.ijtsrd.com 6470 | Volume 2 | Issue – 6 | Sep | Volume – 2 | Issue – 6 | SepOct 2018 nd Cement , Ch. Damodhar Naidu, Bothsa Kumari Student, Assistant Professor f Institutions, Bobbili, Andhra Pradesh, India

Fly Ash is the waste material, which is obtained after burning coal in Thermal Power Plants. It can be used as a stabilizer for soil due to its pozzolanic effect or hardening property under favourable conditions of moisture and compaction. This project aims at increasing the strength of poorly graded soils by using Fly Ash and cement as admixtures. Some percentage of Fly Ash without any additives was utilized so as to reduce the cost of construction and this is a good method for disposal of it. Fly Ash was added in various percentages like 10, 20, 30 and 40 percentages (% by volume). Initially all basic Geotechnical properties of the soil such as liquid limit, plastic limit, shrinkage limit, Grain Size Analysis, Specific Gravity, Free Swell Index, Unconfined Compressive Strength, OMC and MDD were determined. Later on the stabilized mixes were tested for CBR (California Bearing Ratio) which is an indirect measurement of strength. After the detailed experimental investigation it is observed that 30% addition of Fly Ash has shown maximum strengths, so that to obtain much more strengths cement was added in 2, 5, 8 and 10 percentages to this optimum mix of Fly Ash with soil. After that the soil mixes were tested for CBR (California Bearing Ratio) to check it's feasibility in Flexible Pavement constructions. The strengths were checked in both Unsoaked and soaked conditions and at various curing periods like 7 and 28 Days. Among all proportions 30% Fly Ash+8 % of the cement has shown maximum strengths, so that it was decided as optimum mix. Maximum strengths were obtained at 28 days curing period for all proportions of mixes so that this period is decided as optimum curing period. Eventually this project work facilitates an economical, strong and durable construction material for Flexible Pavements.

I.
INTRODUCTION Soil is the cheapest available various construction-related purposes. In this connection, utilization of by-products like Fly Ash as suitable ingredients for geotechnical construction is necessary. Soil improvement is necessary for local soils in many places. Soils with low bearing capacities underlying heavy structures are always problematic from the geotechnical engineering point of view. It is essential to overcome this problem by strengthening the soil. Precautions can be taken by modifying the local soils, which can be achieved either by mechanical or chemical stabilization.
There are many methods available for soil stabilization. For chemical stabilization of soils, there are many additives available such as lime, cement, gypsum and Fly Ash. Among all of them, the cheapest one. Soil stabilization by means of Fly Ash has environmental benefits in preventing pollution of water and air that can result from its mere disposal near thermal power plants. Most of the sub grade soils can be stabilized by mean Many research results have indicated that Fly Ash is an effective material and also has the potential application to stabilize soft sub of Fly Ash is prominent essentially through the reactivity, and the California soil-Fly Ash mixes soil increases due to the pozzolanic reaction. Unconfined compressive strength (UCS) increases with curing periods for soil mixtures, and this is primarily due to the pozzolanic reaction. The increase in percentage content of Fly Ash in Fly Ash-soil mixtures leads to decrease in dry

Cement (OPC 43 grade), CBR
Soil is the cheapest available material utilized for related purposes. In this products like Fly Ash as suitable ingredients for geotechnical construction is necessary. Soil improvement is necessary for local with low bearing capacities underlying heavy structures are always problematic from the geotechnical engineering point of view. It is essential to overcome this problem by strengthening the soil. Precautions can be taken by modifying the h can be achieved either by mechanical or chemical stabilization.
There are many methods available for soil stabilization. For chemical stabilization of soils, there are many additives available such as lime, cement, gypsum and Fly Ash. Among all of them, Fly Ash is the cheapest one. Soil stabilization by means of Fly Ash has environmental benefits in preventing pollution of water and air that can result from its mere disposal near thermal power plants. Most of the sub grade soils can be stabilized by means of admixtures. Many research results have indicated that Fly Ash is an effective material and also has the potential application to stabilize soft sub-grade soils. The effect of Fly Ash is prominent essentially through the reactivity, and the California bearing ratio (CBR) of Fly Ash mixes soil increases due to the pozzolanic reaction. Unconfined compressive strength (UCS) increases with curing periods for soil-Fly Ash mixtures, and this is primarily due to the pozzolanic rcentage content of Fly soil mixtures leads to decrease in dry International Journal of Trend in Scientific Research and Development (IJTSRD) ISSN: 2456 @ IJTSRD | Available Online @ www.ijtsrd.com unit weight, which is attributed to the low specific gravity of Fly Ash. The addition of a small percentage of cement to soil-Fly Ash mixture increases the unconfined compressive strength value. of cement on the behaviour of sandy soil has been studied and it has been reported that the addition of cement increases the stiffness as well as peak strength. Brittle behaviour is more marked in soil Ash-cement mixes than in soil-fly-ash with concurrent increase in UCS value. low dry unit weight and exerts less lateral earth pressure. The use of class F Fly Ash amended soils as highway base materials has been investigated. Some researchers have suggested that the performance analysis of Fly Ash should be based upon laboratory tests such as index properties, compaction, unconfined compressive strength and CBR tests of a specific soil. The strength approach can be applied to estimate the optimum mixture design. The literature review has indicated that the strength gain due to stabilization depends upon several factors: Fly Ash content mounding water content, compaction delay and curing period.
The use of Fly Ash in geotechnical engineering applications such as construction of highway embankments, different layers of road pavement etc. is increasing. In view of the above, the objective of this study was to investigate the strength properties of soil-Fly Ash and soil-Fly Ash-cement mixtures.

II.
MAJOR FORMAT GUIDELINES METHODOLOGY: Materials Used: Fly Ash: For the present study Fly Ash was collected from the National Thermal Power Corporation (NTPC), which is located at paravada in Visakhapatnam.

Cement:
The cement used in this project work is OPC43 grade (Nagarjuna cement) which is collected from the local construction site.

LABORATORY TESTING:
The following tests were conducted on poorly graded sand. The index and engineering properties of poorly graded sand were determined. unit weight, which is attributed to the low specific gravity of Fly Ash. The addition of a small percentage Fly Ash mixture increases the value. The influence of cement on the behaviour of sandy soil has been studied and it has been reported that the addition of cement increases the stiffness as well as peak strength. Brittle behaviour is more marked in soil-Fly ash-fibre mixes value. Fly Ash has low dry unit weight and exerts less lateral earth pressure. The use of class F Fly Ash amended soils as highway base materials has been investigated. Some ggested that the performance analysis of Fly Ash should be based upon laboratory tests such as index properties, compaction, unconfined compressive strength and CBR tests of a specific soil. The strength approach can be applied to estimate the ure design. The literature review has indicated that the strength gain due to stabilization depends upon several factors: Fly Ash content mounding water content, compaction delay and curing The use of Fly Ash in geotechnical engineering ns such as construction of highway embankments, different layers of road pavement etc. is increasing. In view of the above, the objective of this study was to investigate the strength properties of cement mixtures.

FORMAT GUIDELINES
For the present study Fly Ash was collected from the National Thermal Power Corporation (NTPC), which is located at paravada in The cement used in this project work is ) which is collected The following tests were conducted on poorly graded sand. The index and engineering properties of poorly essive Strength Test IV. CONCLUSIONS It is observed from all experimental results that the certain proportions of Fly Ash added to the soil improved the CBR values. The optimum content of the Fly Ash was the soil at both Un soaked & soaked conditions. The optimum content of the cement was decided as 8% for optimum mix of Fly Ash soaked & soaked conditions. Maximum strengths were obtained at 28 days curing period for all proportions of mixes so that this period is decided as optimum curing period The percentage increase in Fly Ash increas maximum dry density and decreases the optimum moisture content. The percentage increases in cement and optimum percentage of Fly Ash (30%) combination leads to the increase in maximum dry density and decreases the moisture content. experimental results that the certain proportions of Fly Ash added to the soil improved the CBR values. The optimum content of the Fly Ash was 30% for the soil at both Un soaked & soaked conditions. The optimum content of the cement was decided for optimum mix of Fly Ash-soil at both un soaked & soaked conditions. Maximum strengths were obtained at 28 days curing period for all proportions of mixes so that this period is decided as optimum curing period The percentage increase in Fly Ash increases the maximum dry density and decreases the optimum The percentage increases in cement and optimum percentage of Fly Ash (30%) combination leads to the increase in maximum dry density and decreases the moisture content.