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ABSTRACT
Polymer concrete is an innovative and modern material, which excellently complies with all the strict requirements on durability, chemical resistance, and which, at the same time, offers high mechanical strength. Synthetic polymers which are condensates of epichloro-hydrin and a suitable polyhydroxyl material most commonly used polyhydroxyl material is bisphenol. Epoxy resins used for PC are typically two-component systems. One component is the epoxy resin and the second component is the hardener or curing agent. Epoxy resins form strong bonds with portland cement concrete, steel, and most construction materials. They are resistant to most chemicals and can be formulated to cure under many moisture and temperature conditions. With the addition of fly-ash in epoxy resin –fly-ash composite the compressive strength has been found to increase with increase in fly ash particles. This increase is attributed to hollowness of fly-ash particles & strong interfacial energy between resin & fly-ash. In this study fly ash and epoxy resin are used in the preparation of polymer concrete. Utilization of waste such as fly ash and epoxy in polymer concrete is promising. it may enhance the physical properties and mechanical strength of the polymer concrete.
CHAPTER 1
INTRODUCTION
GENERAL
In the modern building materials and construction industry the role of concrete is
increasing day by day. As a construction material, concrete is the largest production of all other materials. The increase in demand for the ingredients of concrete is met by partially or fully replacement of materials by the waste materials which is obtained by means of various industries
Fly ash, a principal by-product of the coal-fired power plants, is well accepted as a pozzolanic material that may be used either as a component of blended Portland cement. Fortunately, a waste product can be substituted for large portions of Portland cement, significantly improving concrete’s environmental characteristics.
strength of the concrete. Furthermore, the fact that fly ash contains very fine particle increases compactness in the concretes or mortar and causes filling of the spaces. Using the fly ash in the concrete generally increases the workability of the fresh concrete, decreases the bleeding, decreases the hydration temperature, decreases the permeability of the hardened concrete, increases resistance of the concrete to the chemical effects, and decreases the cost.
1.2. Polymer Concrete
Polymer concrete (PC) is a composite material in which the aggregate is bound together in a matrix with a polymer binder. The composites do not contain a hydrated cement phase, although Portland cement can be used as an aggregate or filler. Binder of polymer concrete is crucial for improved strength in relation to ordinary concrete, and particularly for chemical resistance.
Some popularly used polymers are listed below:
Urethanes: These are polymers and copolymers produced by the reaction of isocyanides with polyols.
Acrylics: These are polymers and copolymers of the esters of acrylic and methecrylic acids.
Styrene butadiene resins (SBR): SBR resins are basically synthetic rubber in
solution.
Vinyl: This is a general term for substituted ethylene’s and their copolymers such as polyethylene, polystyrenes.
Epoxies: Synthetic polymers which are condensates of epichloro-hydrin and a suitable polyhydroxyl material most commonly used polyhydroxyl material is bisphenol.
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Polymer Concrete composites possess a unique combination of properties
dependent upon the formulation. These include:
• Rapid curing at ambient temperatures from –18 to +40 C (0 to 104 F).
• High tensile, flexural, and compressive strengths.
• Good adhesion to most surfaces.
• Good long-term durability with respect to cycles of freezing and thawing.
• Low permeability to water and aggressive solutions.
• Good chemical resistance.
• Light weight.
1.2.1 Benefits of Polymer Concrete
• Impervious to liquids, small number of pores, absolute tightness.
• High resistance to corrosive chemical substances, including acids and bases
• Does not require any maintenance
• No erosion
• Reduces costs of maintenance and exploitation
• Resistance to changing weather conditions and atmospheric factors
1.3 Epoxy Polymer Concrete:
Epoxy resins used for PC are typically two-component systems. One component is the epoxy resin and the second component is the hardener or curing agent. Most epoxy resins are condensation products of Bisphenol A and Epichlorohydrin. Because of their structure, epoxy resins form strong bonds with portland cement concrete, steel, and most construction materials.
Epoxy resin cure times and strengths can vary dramatically. Epoxies tend to be slow-setting and continue to gain strength for weeks; however, they can be formulated to cure rapidly. They are resistant to most chemicals and can be formulated to cure under many moisture and temperature conditions. They have low curing shrinkage, good adhesion properties, high tensile strengths, and excellent abrasion resistance. Epoxy resins tend to have high viscosity and puttylike mortar consistency that may be sticky to finish.
The two-component systems are normally mixed at a resin to-hardener ratio of either 1:1 or 2 (resin):1 (hardener) by volume. Varying the specified ratio of the two components can significantly decrease mechanical and chemical properties.
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Batching should be done in complete units or by using accurate volumetric or weight measures. Acceptable tolerance of the mixing ratio is plus or minus 5 percent, although variations of less than 2 percent are recommended. The individual components should be thoroughly mixed before combining them with the aggregate or filler system. Equipment available for automatic metering of resins insures that proper mix ratios are obtained.
Epoxy PCs can be user prepared with the many formulations of epoxy resins that are available. The selection of the material for a particular application should be based on specific manufacturer's product information and field performance data. Epoxy resins are available for use in a variety of application temperature conditions. The ratio of the two components should never be adjusted to change the curing time. Epoxy resins are considered allergenic; safe handling practices must be exercised.
1.4 Applications of Polymer Concrete
Precast PC utility components include a variety of structures used in various industries and in general construction projects. The types of PC structures and structural components currently being commercially produced are shown below
Architectural panels and facades
Transportation
Electrical insulators
Hydraulic structures
1.5 FLYASH
Fly ash is a finely divided residue that is usually the result of the combustion of powdered coal in boilers at about 2,500 degrees collected by precipitations. There was a time when power plants, steel mills, and other large producers of this form of pozzolana paid to have the by-product hauled away. That was until fly ash was discovered to be a useful product.
Fly ash is removed from the combustion gases by the dust collection system, either mechanically or by using electrostatic precipitators, before they are discharged to the atmosphere. Fly ash particles are typically spherical, finer than Portland cement and lime, ranging in diameter from less than 1μm to not more than 150 μm.
Worldwide, the estimated annual production of coal ash in 1998 was more than 390 million tons. The main contributors for this amount were china and India. Only about 14 percent of this flyash was utilized, while the rest was disposed in landfills (Malhotra 1999). By the year 2010, the amount of fly ash produced worldwide is estimated to be about 780 million tons annually (Malhotra 2002).
Fly ash is a by-product material chemical constituents can vary considerably but all fly includes Silicon Dioxide (SiO2), Calcium Oxide (CaO) also known as Lime, Iron (III) Oxide (FeO2), Aluminum Oxide (Al2O3)
1.5.1 Characteristics of Fly Ash
The characteristics of fly ash that make it valuable for use in concrete are its
(1) High fineness (ranging in size between 10 and 100 micron),
(2) Low carbon content,
(3) Uniformity,
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(4) High percentage of fused silica and
(5) Mostly spherical shape, which contributes toward great plasticity.
1.5.2 Benefits of Fly Ash
Environmental Benefits
Supplementing cementitious materials with fly ash reduces Portland Cement demand
Reduces volume of landfilled fly ash
Conserves water by reducing water demand in concrete mixes
Physical/Mechanical Benefits
Increased Strength
Decreases Permeability
Generally Increases Durability
Increased Sulfate Resistance (Class F)
Reduces Water Demand/ Increases Workability
Reduces Segregation and Bleeding
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CHAPTER 2
LITERATURE REVIEW
Ashok Kumar.Ȧ , Gurpreet SinghḂ and Niraj Bala Evaluation of Flexural Strength of Epoxy Polymer Concrete with Red Mud and Fly Ash,.Department of Mechanical Engineering, Baba Banda Singh Bahadur Engineering College, Fatehgarh Sahib, Punjab, IndiaAccepted 26 November 2013, Available online 01 December 2013, Vol.3, No.5 (December 2013).
In this study fly ash and red mud solid waste are used in the preparation of polymer concrete. Utilization of waste such as fly ash and red mud in polymer concrete is promising; it may enhance the physical properties and mechanical strength of the polymer concrete. The mechanical properties of PCs with variation of different compositions of fly ash (8, 12%), red mud (12, 25%) and resin (30, 35%) has been investigated. The silica powder in different percentage (10, 15%) used as filler in polymer concrete has enhanced the mechanical properties of polymer concrete. The casted PCs were also investigated for their flexural strength.(For the preparation of samples Orthogonal array of Technique of Design of Experiments) is used). The PCs specimen with 35% resin, 25% fly ash and 15% silica fume resulted in maximum flexural strength. Generally, PC’s containg fine fillers may result in high mechanical strength due to high molecular compaction. The values of flexural strengths were 21.53 MPa. The amount of resin and filler in chemical composition of the fabricated PCs has great influence on identification of the maximum physical strength. The PC specimens with 35% resin, 25% fly ash and 15% silica fume resulted in maximum flexural strength. Generally, fine fillers results in high mechanical strength as the fine fillers have high molecular compaction.
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Bhikshma.A*a, K. Jagannadha Raob :EXPERIMENTAL STUDY ON BEHAVIOR OF POLYMER CEMENT CONCRETE Vol. 11, No. 5 (2010) Pages 563-573 a Department of Civil Engineering, Osmania University, Hyderabad, India b Department of Civil Engineering, Chaitanya Bharathi Institute of Technology, Gandipet Hyderabad, India.
The objective of the present investigation is to study the behavior of polymer cement concrete in the hardened state. The variables studied include the grade of concrete and dosage of polymer. Five different grades of concrete M20 to M60 with polymer quantities starting from 5% to 10% were used in the present work. There is an increase in the workability of concrete as the polymer content increased, in all the grades of concretes from M20 to M. The increase in strengths of concrete due to the addition of polymer is significant for low strength concretes and marginal for high strength concretes. In general, it is observed that the overall performance of the concrete is improved with the addition of polymer, by weight of cement, for all the grades of concretes tested. However, the effect of polymer on performance of normal concrete is superior to its effect on high strength concrete.
Bhikshma.V, K.Jagannadharao and B. Balaji AN EXPERIMENTAL STUDY ON BEHAVIOUR OF POLYMER CEMENT CONCRETE, Asian Journal Of Civil Engineering (Building And Housing) Vol. 11, No. 5 (2010).
Their investigation is to study the behavior of polymer cement concrete in the hardened state. Polymer as admixture can improve the properties like higher strength and lower water permeability than the conventional concrete. There is an increase in the workability of concrete as the polymer content increased, in all the grades of concretes. 5 % to 10 % of polymer added. The increase in strengths of concrete due to the addition of polymer is significant for low strength concretes and marginal for high strength concretes.
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Çavdar.A, S. Sevin, Y. Kaya and Ş. Bingöl. Balkan Journal Of Electrical & Computer
Engineering, 2014, Vol.2, No.2 The Effects of Cure Conditions on MECHANICAL PROPERTIES OF POLYMER MODIFIED CEMENT MORTAR.
The uses of polymers for various structural applications are gaining popularity throughout the World. In this study, three different types of polymers are added to cement mortars, and then these mortars are cured under three different cure conditions. Thus, it is aimed to investigate their mechanical contributions to mortars and to determine the most suitable cure condition for polymer modified concrete, comparatively. SBR, PSBR, MAD polymers are chosen as polymers. These polymers are added into the mortars in fivedifferent ratios (0.0%, 5%, 10%, 15%, 20%) by volume and the mortars are cured under three different conditions that watering twice a day (FCC), 16 hours in the water - 8 hours out (SCC), one day in the water - one day out (TCC). The mortars modified with MAD polymer show the best performance for chosen polymer addition ratios and also FCC is the most suitable cure condition.
Jane Proszek Gorninskia, Denise C. Dal Molinb, Claudio S. Kazmierczaka, EVALUATION OF MECHANICAL STRENGTH OF ISOPATHTALIC POLYMER CONCRETE WITH FLY ASH., Asian Journal Of Civil Engineering (2004) .
The main aim of their study is to assess the modulus of elasticity of polymer concrete (PC) compounds produced using two types of binders: orthophtalic or isophtalic polyester. The concentrations of polymer used were 12% of orthophtalic polyester and 13% of isophtalic polyester by weight of the dry materials. Fly ash was used as a filler and compositions with 8%, 12%, 16% and 20% of ash by weight of aggregate were studied. Finally they concluded, there was an increase in axial compressive strength as concentrations of fly ash increased. However, all compositions resulted in high-strength concrete. High modulus of elasticity values was obtained and the peak value was 29GPa. These values are comparable to those observed in high-strength portland concrete.
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CHAPTER 3
SCOPE AND OBJECTIVE
OBJECTIVES
The main objective of this investigation is to study the polymer concrete by
using fly ash as cement.
The objectives of this study are listed below:
To study the characterization of polymer concrete.
To study the performance of polymer concrete using fly ash with replacement for cement.
To compare the effectiveness of Polymer concrete and over conventional concrete.
5.1.2 MIX DESIGN CALCULATION FOR M25 GRADES OF CONCRETE:
Given Data:
Characteristics compressive strength
required in the field at 28 days = 25 Mpa
Maximum size of aggregate (angular) = 20 mm
Degree of workability (compaction factor= 0.90
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Degree of quality control = Good
Type of exposure = Mild
Properties Of Materials:
Specific gravity of cement (sc) = 3.15
Specific gravity of coarse aggregate (Sca) = 2.62
Specific gravity of fine aggregate (Sfa) = 2.7
Water absorption of coarse aggregate = 0.6%
Water absorption of fine aggregate = 1%
Free moisture of coarse aggregate = 0 %
Free moisture of fine aggregate = 2%
FLEXYRAL TENSILE STRENGTH
The bed of the testing machine shall be provided with two steel rollers, 38 mm in diameter, on which the specimen is to be supported, and these rollers shall be so mounted that the distance from center to center is 60 cm for 15•0 cm specimens or 40 cm for 10•0 cm specimens, The load shall be applied through two similar roller", mounted at the third points of the supporting span, that is, spaced at 20 or 13•3 cm center to center. The load shall be divided equally between the two loading roller, and all rollers shall be mounted in such a manner that the load applied axially and without subjecting
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the specimen to any torsional stresses or restraints. Procedure is test specimens stored in water at a temperature of 240 to 3O°C for 48 hours before testing shall be tested immediately on removal from the water whilst they are still in a
wet condition. The dimensions of each specimen shall be noted before testing. No preparation of the surfaces is required.