High strength pdf.pdf

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Mix design of M70 concrete

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High strength pdf.pdf

  1. 1. Project Team Members Anik Yadav 09103009 Shayon Ghosh 09102072 Dr B R Ambedkar National Institute of Technology Batch 2009-2013 HIGH STRENGTH (M70) AND HIGH PERFORMANCE CONCRETE Final Year Project Report.
  2. 2. High strength (M70) and High Performance Concrete Page 1 Acknowledgement We take immense pleasure in thanking Professor Dr S .P Singh, Head Department of Civil Engineering NITJ who had been a source of inspiration and for his timely guidance in the conduct of our Project.We would also like to thank Faculty Members of Department of Civil Engineering NIT Jalandharfor their guidance and for providing required resources to complete our Project successfully.
  3. 3. High strength (M70) and High Performance Concrete Page 2 We wish to express our deep sense of gratitude to Non-teaching Faculty of Department of Civil Engineering NIJ for facilitating us and helping us to completing the project work, successfully. Content Page Introduction 3-4 Properties of High performance Concrete 4-7 Methods for achieving High Performance 7-8
  4. 4. High strength (M70) and High Performance Concrete Page 3 High-performance Concrete Parameters. 8-9 Material Selection 9-16 Mix Proportion 16-18 Objective 18-19 Mix Design of M70 19-23 Laboratory tests 24-26 Preparation of Mix 26-31 Test Results 31-33 Graphs 33-36 Conclusion 37
  5. 5. High strength (M70) and High Performance Concrete Page 4 High strength (M70) and High Performance Concrete C O N C R E T E I S D E F I N E D A S “ H I G H - S T R E N G T H C O N C R E T E ” S O L E L Y O N T H E B A S I S O F I T S C O M P R E S S I V E S T R E N G T H M E A S U R E D A T A G I V E N A G E . High performance concrete (HPC) for concrete mixtures possessing high workability, high durability and high ultimate strength. Concrete, whose ingredients, proportions and production methods are specifically chosen to meet special performance and uniformity requirements that cannot be always achieved routinely by using only conventional materials, like, cement, aggregates, water and chemical admixtures, and adopting normal mixing, placing and curing practices. These performance requirements can be high strength, high early strength, high workability, low permeability and high durability for severe service environments, etc. or combinations thereof. Production and use of such concrete in the field necessitates high degree of uniformity between batches and very stringent quality control. High performance concrete (HPC) is a specialized series of concrete designed to provide several benefits in the
  6. 6. High strength (M70) and High Performance Concrete Page 5 construction of concrete structures that cannot always be achieved routinely using conventional ingredients, normal mixing and curing practices. In the other words a high performance concrete is a concrete in which certain characteristics are developed for a particular application and environment, so that it will give excellent performance in the structure in which it will be placed, in the environment to which it will be exposed, and with the loads to which it will be subjected during its design life. It includes concrete that provides either substantially improved resistance to environmental influences (durability in service) or substantially increased structural capacity while maintaining adequate durability. It may also include concrete, which significantly reduces construction time without compromising long-term serviceability. While high strength concrete, aims at enhancing strength and consequent advantages owing to improved strength, the term high- performance concrete (HPC) is used to refer to concrete of required performance for the majority of construction applications without compromising long-term serviceability. While high strength concrete, aims at enhancing strength and consequent advantages owing to improved strength, the term high-performance concrete (HPC) is used to
  7. 7. High strength (M70) and High Performance Concrete Page 6 refer to concrete of required performance for the majority of construction applications. Properties of High performance Concrete • High modulus of elasticity • High abrasion resistance • High durability and long life in severe environments • Low permeability and diffusion • Resistance to chemical attack • High resistance to frost and deicer scaling damage • Toughness and impact resistance • Ease of placement • Chemical Attack • Carbonation
  8. 8. High strength (M70) and High Performance Concrete Page 7 High Modulus of elasticity The modulus of elasticity is a very important mechanical property of concrete. The higher the value of the modulus, the stiffer the material is. Thus, comparing a high performance concrete to a normal strength concrete, it is seen that the elastic modulus for high performance concrete will be higher, thereby making it a stiffer type of concrete. Stiffness is a desirable property for concrete to have because the deflection a structure may experience will be decreased. However, deformations, such as creep, increase in high strength concrete High abrasion resistance Abrasion resistance is directly related to the strength of concrete. This makes high strength HPC ideal for abrasive environments. The abrasion resistance of HPC incorporating silica fume is especially high. This makes silica fume concrete particularly useful for spillways and stilling basins, and concrete pavements or concrete pavement overlays subjected to heavy or abrasive traffic. High durability and long life in severe environments.
  9. 9. High strength (M70) and High Performance Concrete Page 8 Durability problems of ordinary concrete can be associated with the severity of the environment and the use of inappropriate high water/binder ratios. High-performance concrete that have a water/binder ratio between 0.30 and 0.40 are usually more durable than ordinary concrete not only because they are less porous, but also because their capillary and pore networks are somewhat disconnected due to the development of self-desiccation. In high-performance concrete (HPC), the penetration of aggressive agents is quite difficult and only superficial Low permeability and diffusion The durability and service life of concrete exposed to weather is related to the permeability of the cover concrete protecting the reinforcement. HPC typically has very low permeability to air, water, and chloride ions. Low permeability is often specified through the use of a coulomb value, such as a maximum of 1000 coulombs.The dense pore structure of high- performance concrete, which makes it so impermeable, gives it characteristics that make it eminently suitable for uses where a high quality concrete would not normally be considered Resistance to chemical attack For resistance to chemical attack on most structures, HPC offers a much improved performance. Resistance to various sulfates is achieved primarily by the use of a dense, strong concrete of very low permeability
  10. 10. High strength (M70) and High Performance Concrete Page 9 and low water-to-cementing materials ratio; these are all characteristics of HPC. Similarly resistance to acid from wastes is also much improved. High resistance to frost and deicer scaling damage Because of its very low water-cementing materials ratio (less than 0.30), it is widely believed that HPC should be highly resistant to both scaling and physical breakup due to freezing and thawing. There is ample evidence that properly air-entrained high performance concretes are highly resistant to freezing and thawing and to scaling Toughness and impact resistance Both normal-strength concrete and high-strength concrete are brittle, with the degree of brittleness increasing with increasing strength. The dynamic mechanical performance of high-strength concrete (HSC) under impact or fatigue loading has received increasing attention in recent years because of the rapid adoption of higher strength concrete in bridges, pavements, and marine structures, and several researchers have studied the impact or fatigue performance of concrete. Many experimental results have indicated that the characteristics and microstructure of both the interfacial zone and the bulk HSC are improved by incorporating silica fume. As well, the addition of steel fibers can effectively restrain the initiation and propagation of crack under stress, and improve the toughness. Ease of Placement
  11. 11. High strength (M70) and High Performance Concrete Page 10 High performance concrete can also be highly workable self-compacting concrete which is type of HPC which can be easily placed even dense reinforcement where vibrators can’t be used. Chemical Attack For resistance to chemical attack on most structures, HPC offers a much improved performance. Resistance to various sulfates is achieved primarily by the use of a dense, strong concrete of very low permeability and low water-to-cementing materials ratio; these are all characteristics of HPC. Similarlyresistance to acid from wastes is also much improved Carbonation HPC has a very good resistance to carbonation due to its low permeability. It was determined that after 17 years the concrete in the CN Tower in Toronto had carbonated to an average depth of 6 mm (0.24 in.). The concrete mixture in the CN Tower had a water-cement ratio of 0.42. For a cover to the reinforcement of 35 mm (1.4 in.), this concrete would provide corrosion protection for 500 years. For the lower water cementing materials ratios common to HPC, significantly longer times to corrosion would result, assuming a crack free structure. In practical terms, uncracked HPC cover concrete is immune to carbonation to a depth that would
  12. 12. High strength (M70) and High Performance Concrete Page 11 Methods for achieving High Performance In general, better durability performance has been achieved by using high-strength, low W/c ratio concrete. Though in this approach the design is based on strength and the result is better durability, it is desirable that the high performance, namely, the durability, is addressed directly by optimizing critical parameters such as the practical size of the required materials. Two approaches to achieve durability through different techniques are as follows. 1. Reducing the capillary pore system such that no fluid movement can occur is the first approach. This is very difficult to realize and all concrete will have some interconnected pores. 2. Creating chemically active binding sites which prevent transport of aggressive ions such as chlorides is the second more effective method.
  13. 13. High strength (M70) and High Performance Concrete Page 12 High-performance Concrete Parameters. Permeation is a major factor that causes premature deterioration of concrete structures. The provision of high-performance concrete must center on minimizing permeation through proportioning methods and suitable construction procedures (curing) to ensure that the exposure conditions do not cause ingress of moisture and other agents responsible for deterioration. It is important to identify the dominant transport phenomenon and design the mix proportion with the aim of reducing that transport mechanism which is dominant to a predefined acceptable performance limit based on permeability. 9The parameter to be controlled for achieving the required performance criteria could be any of the following. (1) Water/ (cement + mineral admixture) ratio (2) Strength
  14. 14. High strength (M70) and High Performance Concrete Page 13 (3) Densification of cement paste (4) Elimination of bleeding (5) Homogeneity of the mix (6) Particle size distribution (7) Dispersion of cement in the fresh mix (8) Stronger transition zone (9) Low free lime content (10) Very little free water in hardened concrete Material Selection The main ingredients of HPC are almost the same as that of conventional concrete. These are 1) Cement 2) Fine aggregate 3) Coarse aggregate 4) Water
  15. 15. High strength (M70) and High Performance Concrete Page 14 5) Mineral admixtures (fine filler and/or pozzolanic supplementary cementation materials) 6) Chemical admixtures (plasticizers, superplastisizers, retarders, air- entraining agents) Cement There are two important requirements for any cement: (a) strength development with time and (b) facilitating appropriate rheological characteristics when fresh. 1) High C3A content in cement generally leads to a rapid loss of flow in fresh concrete. Therefore, high C3A content should be avoided in cements used for HPC. 2) The total amount of soluble sulphate present in cement is a fundamental consideration for the suitability of cement for HPC.
  16. 16. High strength (M70) and High Performance Concrete Page 15 3) The fineness of cement is the critical parameter. Increasing fineness increases early strength development, but may lead to rheological deficiency. 4) The super plasticizer used in HPC should have long molecular chain in which the sulphonate group occupies the beta position in the poly condensate of formaldehyde and melamine sulphonate or that of naphthalene sulphonate. 5) The compatibility of cement with retarders, if used, is an important requirement. Coarse aggregates The important parameters of coarse aggregate that influence the performance of concrete are its shape, texture and the maximum size. Since the aggregate is generally strongerthan the paste, its strength is not a major factor for normal strength concrete, or for HES and VES concretes. However, the aggregate strength becomes important in the case of highperformance concrete. Surface texture and mineralogy affect the bond between the aggregates and the paste as well as the stress level
  17. 17. High strength (M70) and High Performance Concrete Page 16 at which micro cracking begins. The surface texture, therefore, may also affect the modulus of elasticity, the shape of the stress-strain curve and to a lesser degree, the compressive strength of concrete. Since bond strength increases at a slower rate than compressive strength, these effects will be more pronounced in HES and VES concretes. Tensile strengths may be very sensitive to differences in aggregate surface texture and surface area per unit volume. Fine aggregate Fine aggregates (FA) with a rounded particle shape and smooth texture have been found to require less mixing water in concrete and for this reason are preferable in HSC. HSC typically contain such high contents of fine cementations materials that the grading of the FA used is relatively unimportant. However, it is sometimes helpful to increase the fineness modulus (FM) as the lower FM of FA can give the concrete a sticky consistency (i.e. making concrete difficult to compact) and less workable fresh concrete with a greater water demand. Therefore, sand with a FM of about 3.0 is usually preferred for HSC (ACI 363R, 1992). Compressive strength of coarse aggregate To make high-strength concrete we must obviously use coarse aggregate that has a high compressive strength to prevent rupture from occurring
  18. 18. High strength (M70) and High Performance Concrete Page 17 in the coarse aggregate. We must therefore find coarse aggregates that come from quarries that produce rocks with compressive strengths above 16,500 psi7 and absolutely avoid rocks that are too soft or which present cleavage planes. So before making laboratory trial batches, we should determine the compressive strengths of all the coarse aggregates economically available. Yet, as already noted, it is not necessarily the strongest coarse aggregate which will produce the strongest concrete, since the bond of the hydrated cement to that same aggregate must be taken into account. Shape of coarse aggregate Because the bond between the coarse aggregate and the hydrated cement is more of a mechanical type at the beginning, to make high-strength concrete we ought to use a cubically shaped crushed stone rather than a natural gravel or a crushed gravel. The type of crusher used by the aggregate producer is important in this respect. Furthermore, the surfaces of the coarse aggregate must be clean and free of any dust which would impair mechanical bonding. In certain cases, washing of the aggregate may prove necessary. Careful examination of aggregate samples from local quarries is sufficient to choose the coarse aggregate that offers the most useful characteristics from this point of view. Maximum size of coarse aggregate We could show that for a given aggregate there is a relation between its maximum diameter and the maximum compressive strength possible from concrete made with it. The absolute maximum strength seems to be obtained with aggregates having a maximum size of 3⁄8 or 1⁄2 inch.8
  19. 19. High strength (M70) and High Performance Concrete Page 18 Standard coarse aggregates of Number 4 to- 3⁄8-inch 9 or Number 4-to- 5⁄8-inch10 sizes are the most suitable. Effect of Aggregate Type The intrinsic strength of coarse aggregate is not an important factor if water-cementratio falls within the range of 0.50 to 0.70, primarily due to the fact that the cement-aggregate bond or the hydrated cement paste fails long before aggregates do.It is, however, not true for very high strength concretes with very low water-cement ratio of 0.20 to 0.30. For such concretes, aggregates can assume the weaker-link role and fail in the form of trans granular fractures on the failure surface. However, the aggregate minerals must be strong, unaltered, and fine grained in order to be suitable for very high strength concrete. Intra- and inter-granular fissures partially decomposed coarse-grained minerals, and the presence of cleavages and lamination planes tend to weaken the aggregate, and therefore the ultimate strength of the concrete. The compressive strength and elastic modulus of concrete are significantly influencedby the mineralogical characteristics of the
  20. 20. High strength (M70) and High Performance Concrete Page 19 aggregates. Crushed aggregates from fine-grained debris and limestone give the best results. Concretes made from smooth river gravel and from crushed granite containing inclusions of a soft mineral are relatively weaker in strength. There exists a good correlation between the compressive strength of coarse aggregate and its soundness expressed in terms of weight loss. There exists a close correlation between the mean compressive strengths of the aggregate and the compressive strength of the concrete, ranging from 35 to 75 MPa, at both 7 days and 28 days of age. Effect of Aggregate Size The use of larger maximum nominal size of aggregate affects the strength in several ways. First, since larger aggregates have less specific surface area and the aggregate-pastebond strength is less, the compressive strength of concrete is reduced. Secondly, for a given volume of concrete, using larger aggregate results in a smaller volume of paste thereby providing more restraint to volume changes of the paste. This may induce additional stresses in the paste, resulting in micro cracks prior to application of load, which may be a critical factor in very high
  21. 21. High strength (M70) and High Performance Concrete Page 20 strength (VHS) concretes. Therefore, it is the general consensus that smaller size aggregate should be used to produce high performance concrete. It is generally suggested that 10 to 12 mm is the appropriate maximum size of aggregates for making high strength concrete. However, adequate performance and economy can also be achieved with 20 to 25 mm maximum size graded aggregates by proper proportioning with a mid- range or high-range water reducer, high volume blended cements, and coarse ground Portland cement. Change in emphasis from water- cementations material ratio versus strength relation to water-content versus durability relation will provide the incentive for much closer control of aggregate grading than in the current practices. A substantial reduction in water requirement can be achieved by using a well-graded aggregate. Mineral admixtures Mineral admixtures form an essential part of the high-performance concrete mix. These are used for various purposes, depending upon their
  22. 22. High strength (M70) and High Performance Concrete Page 21 properties. More than the chemical composition, mineralogical and granulometric characteristics determine the influence of mineral admixture's role in enhancing properties of concrete. The fly ash (FA), the ground granulated blast furnace slag (GGBS) and the silica fume (SF) has been used widely as supplementary cementations materials in high performance concrete. These mineral admixtures, typically fly ash and silica fume (also called condensed silica or micro silica), reduce the permeability of concrete to carbon dioxide (CO2) and chloride-ion penetration without much change in the total porosity. These pozzolanas react with OPC in two ways-by altering hydration process through alkali activated reaction kinetics of a pozzolanas called pozzolanic reaction and by micro filler effect. In pozzolanic reaction the pozzolanas react with calcium hydroxide, Ca(OH)2, (free lime) liberated during hydration of cement, which comprises up to 25 per cent of the hydration product, and the water to fill voids with more calcium-silicate- hydrate (non-evaporable water) that binds the aggregate particles together.
  23. 23. High strength (M70) and High Performance Concrete Page 22 The pozzolanas may also react with other alkalis such as sodium and potassiumhydroxides present in the cement paste. These reactions reduce permeability, decrease the amounts of otherwise harmful free lime and other alkalis in the paste, decrease free water content, thus increase the strength and improve the durability. Fly ash used as a partial replacement for cement in concrete, provides very good performance. Concrete is durable with continued increase in compressive strength beyond 28 days. There is little evidence of carbonation, it has low to average permeability and good resistance to chloride-ion penetration. Chloride-ion penetration rating of high volume fly ash (HVFA) concrete is less than 2000 coulombs, which indicate a very low permeability concrete. It continues to improve because many fly ash particles react very slowly, pushing the coulomb value lower and lower. Silica fume not only provides an extremely rapid pozzolanic reaction, but its very fine size also provides a beneficial contribution to concrete. Silica fume tends to improve both mechanical properties and durability. Silica fume concretes continue to gain strength under a variety of curing conditions, including
  24. 24. High strength (M70) and High Performance Concrete Page 23 unfavorable ones. Thus the concretes with silica fume appear to be more robust to early drying than similar concretes that do not contain silica fume. Silica fume is normally used in combination with high-range water reducers and increase achievable strength levels dramatically. Since no interaction between silica fume, ground granulated blast- furnace slag and fly ash occurs, and each component manifests its own cementations properties as hydration proceeds, higher strength and better flow ability can be achieved by adding a combination of SF, FA and GGBFS to OPC which provides, a system with wider particle-size distribution. HVFA concrete incorporating SF exceeds performance of concrete with only FA. The key to developing OPC-FA-SF and OPC-GBSF- SF concretes without reduction in strength is to incorporate within the mixture adequate amounts of OPC and water. Using both silica fume and fly ash, the strength at 12 hours has been found to improve suddenly over similar mixes with silica fume alone. This phenomenon has been attributed to the liberation of soluble alkalis from the surface of the fly ash.
  25. 25. High strength (M70) and High Performance Concrete Page 24 Admixtures High Range Water Reducing Admixtures (HRWA) :These are the second generation admixture and also called as Super plasticizers. These are synthetic chemical products made from organic sulphonate of type RSO3, where R is complex organic group of higher molecular weight produced under carefully controlled condition: The commonly used super plasticizer are as follows: i) Sulphonate melamine formaldehyde condensate (S M F C) ii) Sulphonated napthalene formaldehyde condensate (S N F C) iii) Modified ligno-sulphonates and other sulphonic esters, acids etc. iv) Polycarboxylate Ether Polymer (PCE) Reduction in W/c Ratio is as follows against the different water reducers admixtures: 1.Water Reducer Admixture: 5-12% Reduction of water. 2.Melamine/Naphthalene based admixtures: It reduces water 16-25 %.
  26. 26. High strength (M70) and High Performance Concrete Page 25 3. Polycarboxylate ether polymer based admixture: It reduces water 20 to 35%. The main objectives for using superplasticizers are the following. (i) To produce highly dense concrete to ensure very low permeability with adequate resistance to freezing-hawing. (ii) To minimize the effect of heat of hydration by lowering the cement content. (iii) To produce concrete with low air content and high workability to ensure high bond strength. (iv) To lower the water-cement ratio in order to keep the effect of creep and shrinkage to a minimum. (v) To produce concrete of lowest possible porosity to protect it against external attacks. (vi) To keep alkali content low enough for protection against alkali- aggregate reaction and to keep sulphate and chloride contents as low as possible for prevention of reinforcement corrosion. (vii) To produce pump able yet non-segregating type concrete.
  27. 27. High strength (M70) and High Performance Concrete Page 26 (viii) To overcome the problems of reduced workability in fiber reinforce concrete and shotcrete. (ix) To provide high degree of workability to the concretes having mineral additives with very low water-cementations material ratios. (x) To produce highly ductile and acid resistant polymer (acrylic latex) concrete with adequate workability and strength. The following types of superplastisizers are used. • Naphthalene-based • Melamine-based • Ligno-sulphonates-based • Polycarboxylate-based • Combinations of above Mix Proportion The main difference between mix designs of HPC and CC is the emphasis laid on performance aspect also (in fresh as well as hardened stages of concrete) besides strength, in case of HPC, whereas in design of CC
  28. 28. High strength (M70) and High Performance Concrete Page 27 mixes, strength of concrete is an important criterion. By imposing the limitations on maximum water–cement ratio, minimum cement content, workability (slum, flow table, compaction factor, and Vee-Bee consistency), etc., it is sought to assure performance of CC; rarely any specific tests are conducted to measure the durability aspects of CC, during the mix design. In HPC, however, besides strength, durability considerations are given utmost importance. To achieve high durability of HPC, the mix design of HPC should be based on the following considerations: i) The water-binder (w/b) ratio should be as less as possible, preferably 0.3 and below. ii) The workability of concrete mix should be enough to obtain good compaction (use suitable chemical admixtures such as super plasticizer (SP)). iii) The transition zone between aggregate and cement paste should be strengthened (add fine fillers such as silica fume (SF)). iv) The microstructure of cement concrete should be made dense and impermeable (add pozzolanic materials such as fly ash (FA), ground granulated blast furnace slag powder
  29. 29. High strength (M70) and High Performance Concrete Page 28 (GGBFSP), SF, etc.) v) Proper curing regime of concrete should be established (this is to overcome the problemsassociated with usual adoption of very low water content and high cement content in HPC mixes. TYPICAL HPC MIX DESIGN METHODS The properties of HPCs not only depend upon the w/b ratio but also vary considerably with the richness of mix and the type and strengths of concrete of aggregates. Workability of HPCs depends upon the type of cement and its compatibility with chemical admixtures, shape of aggregate, method of mixing of ingredients of HPCs, etc. Thus, the properties of materials and mix preparation techniques have very high influence on the HPC mixes, suitable mix proportions cannot be suggested for HPCs. Therefore, any mix design procedure of HPCs can strictly be only a guideline and a separate development of HPC mix in the laboratory for the various ingredients, type of structure and concreting conditions etc., is very much essential. Hence, the HPC mix design can be only application-specific.
  30. 30. High strength (M70) and High Performance Concrete Page 29 It should be noted that the strength increase as the w/c is reduced (provided the compatibility of concrete is maintained), and that for a given w/c, the strength is decreased as a mix is made richer (by adding more cement) beyond a limit. Therefore, the advantage of increase in strength due to lowering of the w/c, which also reduces consequently the workability. Hence, the HPCs require approaches other than the increase of cement content in order to achieve the high strength. Though the strengths are not always true indicators of durability, the high strength associated with the HPCs generally tend to impart also high durability to them, due to reduced w/b and use of pozzolanic admixtures. OBJECTIVE To achieve high strength concrete(M70) without compromising the workability of concrete. Normally when we try to achieve very high strength the mix becomes very stiff and it can’t be pumped on the site .Thus our main aim was to achieve the desired strength with desired workability and other properties like low permeability ,high durability etc.
  31. 31. High strength (M70) and High Performance Concrete Page 30 CRITICAL STUDY OF THE FOLLOWING Variation in compressive strength with respect to water cement ratio and varying proportions of cementation materials. MATERIAL USED  Cement(OPC Cement 43 grade)  Fly Ash  Micro Silica  Coarse Aggregates(20mm & 10mm)  Fine Aggregates  Water  Admixture (Glenium 51) Mix Design Detail of M-70 Target Mean Strength Fck =fck+1.65 s
  32. 32. High strength (M70) and High Performance Concrete Page 31 =70+1.65*5 = 78.25 MPa Where, fck’ – target average compressive strength 28 days. fck- Characteristic compressive strength at 28 days “S” is taken 5 for M30 or above as per IS 10262 Design for 1m3 batch. From Table-2 IS 10262 Maximum water content for 20 mm aggregate – 186 kg for (slump 25mm to 50mm) Estimation of Water Content for 75mm SLUMP. =186+ (15/100)*186 =186+27.9 =213.9 kg/m3 From trials it was found that admixture (super plasticizer) Glenium SKY 51 reduced water content by 30%. Hence arrived water content =213.9*0.7 =149.73 kg/m3
  33. 33. High strength (M70) and High Performance Concrete Page 32 *Note: modification in water content has been done in accordance with the standard lab result various trial mixtures for required slump/flow requirement and strength, which are not specified in IS codes. Calculation of Cementations Material From trial an error water cement ratio was found 0.26 Cementations Content: 149.73/0.26 = 576 kg/m3 Content of OPC : -0.77*576 =434 Kg/m3 Content of Fly Ash : -0.17*576 =98 kg/m3 Micro Silica : 0.06*576 =35 kg/m3 Volume of Coarse Aggregates and Fine Aggregates Volume of 20mm aggregates = 0.23 Volume of 10mm aggregates = 0.35
  34. 34. High strength (M70) and High Performance Concrete Page 33 Volume of Fine Aggregates = 1-(0.23+0.35) =0.42 Mix Calculation Mix calculation per unit volume of Concrete as follows: Volume of Concrete : 1m3 Volume of Cement : (Mass of Cement /Specific gravity)*(1/1000) = (434/3.14)*(1/1000) =0.138 m3 Volume of Fly Ash : (Mass of Fly Ash/Specific gravity)*(1/1000) = (98/1.93)*(1/1000) =0.050 m3 Volume of Micro silica : ( Mass of Micro silica/ specific Gravity)*(1/1000) = (35/2.2)*(1/1000) =0.0159 m3 Volume of Water =(Mass of Water/Specific Gravity of Water)*(1/1000)
  35. 35. High strength (M70) and High Performance Concrete Page 34 = (149.73/1)*(1/1000) =0.149 m3 Volume of Admixture = (Mass of Glenium sky 777/Specific Gravity of Admixtures)*(1/1000) = (7.02/1.1)*(1/1000) = 0.00638 m3 Volume of All in one Aggregates : (1-(0.138+0.050+0.0159+0.150)) =0.6471m3 Mass of CourseAggregates 20mm: =0.6471*volume of 20mm aggregates*Specific gravity*1000 =0.6471*0.23*2.60*1000 =386 kg/m3 Mass of Coarse aggregates 10 mm: = 0.6471*volume of 10mm aggregates *specific gravity*1000 =0.6471*0.35*2.59*1000 =586 kg/m3 Mass of fine aggregates: = 0.6471 *volume of fine aggregates* specific gravity*1000 =0.6471*0.42*2.55*1000 =693 kg/m3 Obtain Mix Proportion for Trial Mix
  36. 36. High strength (M70) and High Performance Concrete Page 35 Cement : 434 kg/m3 Fly Ash : 98 kg/m3 Micro Silica : 35 kg/m3 Water : 149 kg/m3 Coarse aggregates 20 mm: 356 kg/m3 Coarse aggregates 10 mm: 586 kg/m3 Fine aggregates : 693 kg/m3 Water Cement Ratio : 0.26 Trial Mix Batch Of 0.03 Cement : 13.02 kg Fly Ash : 2.94 kg Micro Silica : 1.05 kg Water : 4.47 kg
  37. 37. High strength (M70) and High Performance Concrete Page 36 Coarse aggregates 20 mm : 10.95 kg Coarse aggregates 10 mm : 17.58 kg Fine aggregates : 20.76 kg Water Cement Ratio : 0.26 Two other trial mixes were as follows BATCH A Cement : 13.60 kg Fly Ash : 1.7 kg Micro Silica : 1.7 kg
  38. 38. High strength (M70) and High Performance Concrete Page 37 Water : 4.47 kg Coarse aggregates 20 mm : 10.95 kg Coarse aggregates 10 mm : 17.58 kg Fine aggregates : 20.76 kg Water Cement Ratio : 0.26 BATCH B Cement : 11.90 kg Fly Ash : 3.40 kg Micro Silica : 1.70 kg Water : 4.47 kg Coarse aggregates 20 mm : 10.95 kg Coarse aggregates 10 mm : 17.58 kg Fine aggregates : 20.76 kg Water Cement Ratio : 0.26
  39. 39. High strength (M70) and High Performance Concrete Page 38 Laboratory Tests Various laboratory tests were performed during our training period has be listed below with their obtained values and permissible limit. 1. Determination of Specific Gravity by Pycnometer Method. Permissible Limit- 2.4 to 2.9 Obtained Values Coarse Aggregate : 2.6 Fine Aggregate : 2.59 2. Determination of Moisture Content Of Aggregates Permissible Limit: Less than 2% for coarse aggregate and less than 2.3% for fine aggregates. Obtained Value Coarse aggregate: 0.5% Fine aggregate : 1.5% 3. Determination of Impact Value of Coarse aggregate Permissible Limit : 30% Obtained Value : 18.76% 3. Crushing Test
  40. 40. High strength (M70) and High Performance Concrete Page 39 Permissible Limit : 30% Obtained Value : 17.67% 3. Determination of Initial and Final Setting Time of Cement Permissible Limit: Initial Setting Time: As per IS Code it should not be less than 30 minutes for general purpose. Final Setting Time: As per IS Code it should Not be more than 10 Hours. Obtained Value Initial Setting Time: 48 minutes Final Setting Time: 6 hours 47 minutes. Determination of Sieve Analysis of Aggregates
  41. 41. High strength (M70) and High Performance Concrete Page 40 Sieve Analysis Fine Aggregates Sieve Size (mm) Weight Percentage Cumulative % passed Permissible Limit Remark 10 0 0 0 100 100 Passed 4.75 172 9.11 9.11 90.89 90 to 100 2.36 160 8.48 17.59 82.41 75 to 100 1.18 323 17.11 34.70 65.3 55 to 100 600 micro 243 12.11 46.81 53.19 35 to59 300 micron 752 39.85 86.66 13.34 8 to 30 150 micron 196 10.38 97.04 2.96 0 to 10 Pan 41 2.17 99.21 0.79 0 Sieve Analysis 20 mm Aggregates Sieve Size (mm) Weight Percentage Cumulative % passed Permissible Limit Remark 25 0 0 0 100 100 Passed 20 1858.995 9.81 9.81 90.19 85 to 100 10 1456.308 84.85 94.66 5.34 0 to 20 4.75 51.7335 4.73 99.39 0.61 0 to 5 PAN 11.5595 0.61 100 0 0
  42. 42. High strength (M70) and High Performance Concrete Page 41 Preparation of trial mix. Sieve Analysis 10 mm Aggregates Sieve Size (mm) Weight Percentage Cumulative % passed Permissible Limit Remark 25 0 0 0 100 100 Passed 20 1858.995 9.81 9.81 90.19 85 to 100 10 1588.958 83.85 93.66 6.34 0 to 20 4.75 104.7935 5.53 99.19 0.81 0 to 5 PAN 15.3495 0.81 100 0 0
  43. 43. High strength (M70) and High Performance Concrete Page 42
  44. 44. High strength (M70) and High Performance Concrete Page 43
  45. 45. High strength (M70) and High Performance Concrete Page 44 Snaps of Compressive Strength Test
  46. 46. High strength (M70) and High Performance Concrete Page 45
  47. 47. High strength (M70) and High Performance Concrete Page 46 [TYPE A QUOTE FROM THE DOCUMENT OR THE SUMMARY OF AN INTERESTING POINT. YOU CAN POSITION THE TEXT BOX ANYWHERE IN THE DOCUMENT. USE THE DRAWING TOOLS TAB TO CHANGE THE FORMATTING OF THE PULL QUOTE TEXT BOX.]
  48. 48. High strength (M70) and High Performance Concrete Page 47 Test Results
  49. 49. High strength (M70) and High Performance Concrete Page 48
  50. 50. High strength (M70) and High Performance Concrete Page 49 Graphical Representation of Data
  51. 51. High strength (M70) and High Performance Concrete Page 50 0 10 20 30 40 50 60 70 0.25 0.26 0.27 0.28 0.29 0.3 0.31 0.32 0.33 CompressiveStrength(MPa) W/C ratio 28 days Strength Vs W/C Ratio
  52. 52. High strength (M70) and High Performance Concrete Page 51
  53. 53. High strength (M70) and High Performance Concrete Page 52
  54. 54. High strength (M70) and High Performance Concrete Page 53
  55. 55. High strength (M70) and High Performance Concrete Page 54
  56. 56. High strength (M70) and High Performance Concrete Page 55
  57. 57. High strength (M70) and High Performance Concrete Page 56 Conclusion  Our target was to achieve M 70 grade concrete but we could reach up to a compressive strength of 71.21MPa.
  58. 58. High strength (M70) and High Performance Concrete Page 57  But due poor workmanship and professional inexperience we were not able to achieve desired compressive strength, however we were able to achieve compressive Strength of 71.21MPa which was quite closer to our results. Added to that we carried outs trial mixes at various water cement ratios(0.32-0.26) which helped us in understanding the behavior of concreter at lower water cement ratio which was displayed in graphs in previous slides.  We also understood there are various uncertainties associated with the concrete mix design and even smaller or minor things could be crucial and may affect the behavior of concrete.
  59. 59. High strength (M70) and High Performance Concrete Page 58 References High Strength Concrete Journals IS Code: 10262 Ultra High Performance Concretes. Association Francaise de Genie Civil, 2002. Concrete canvas

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