Water plays a key role in cement concrete as it acts as a reactant in the chemical process of hydration that provides concrete its strength over time. The water-cement ratio is an important factor, with lower ratios producing higher strength concrete. Water used for mixing must meet requirements for quality and impurities. Admixtures can be used to improve workability or reduce the water content. Proper curing is also important for achieving design strength and durability of the concrete. Sprayed concrete has advantages over poured concrete such as lower permeability and faster strength gain.
Quality Control in Concrete and Durability factors : An overviewbybyRAJESH PRASAD,IRSE, CPM/M, RVNL. KOLKATA. An interesting and informative presentation....
Concrete Construction: Batching of mixes; casting process, compaction and curing;
requirement of mix design and casting of test cubes – removing cubes from moulds and
curing for strength tests; bar-bending equipments and preparation of reinforcement for
R C C works
Admixtures are added in concrete to improve the quality of concrete.
Fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), Metakaolin (MK), and rice husk ash (RHA)
Possess certain characteristics through which they influence the properties of concrete differently.
Effect of mineral admixtures on the properties of fresh concrete is very important as these properties may affect the durability and mechanical properties of concrete.
Quality Control in Concrete and Durability factors : An overviewbybyRAJESH PRASAD,IRSE, CPM/M, RVNL. KOLKATA. An interesting and informative presentation....
Concrete Construction: Batching of mixes; casting process, compaction and curing;
requirement of mix design and casting of test cubes – removing cubes from moulds and
curing for strength tests; bar-bending equipments and preparation of reinforcement for
R C C works
Admixtures are added in concrete to improve the quality of concrete.
Fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), Metakaolin (MK), and rice husk ash (RHA)
Possess certain characteristics through which they influence the properties of concrete differently.
Effect of mineral admixtures on the properties of fresh concrete is very important as these properties may affect the durability and mechanical properties of concrete.
Lesson: Concrete Technology - Building Materials
The quality of aggregate affect the durability and strength of concrete. Since about 3/4 of the volume of concrete is occupied by aggregate.
Use of chemical admixtures and mineral additives in various kinds of high performance and high strength concrete is essential. I have explained how it works.
Properties of Fresh and Hardened ConcreteRishabh Lala
Properties of Fresh (Workability)
Hardened Concrete (Workability,Permiablitiy,Durablility)
Thermal properties
Micro-cracking of concrete
Mix Design
Rheology
Causes of Damage of Concrete
Pervious Concrete is a special type of concrete with a high porosity used for concrete flatwork applications that allows water from precipitation and other sources to pass directly through, thereby reducing the runoff from a site and allowing groundwater recharge.
These presentations were created during the 2016–2021 B.Arch programme.
Please refer to the references column at the end of each presentation for the information within.
Introduction to admixtures. Standard code definition of admixtures and additives. Various types of admixtures and additives along with their properties. Mechanism for working of admixtures and additives. Effect of admixtures of properties of concrete.
admixture
TYPES OF ADMIXTURE
CHEMICAL ADMIXTURE
AIR ENTERINERS
WATER REDUCERS
SET RETARDERS
SET ACCELERATORS
SUPERPLASTICIZER
MINERAL ADMIXTURE
FLY ASH
SILICA FLUMES
SLAG
FUNCTION OF ADMIXTURE
ADVANTAGES OF ADMIXTURE
vedio link
https://youtu.be/HJzgwpquo7w
Fresh concrete -building materials for engineersmusadoto
General introduction
CONCRETE
is a building Material made from a mixture of gravel ,sand ,cement,water and air ,forming a stone like mass on hardenning.
FRESH CONCRETE
It is a concrete that has not reached the final setting time.
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Improving profitability for small businessBen Wann
In this comprehensive presentation, we will explore strategies and practical tips for enhancing profitability in small businesses. Tailored to meet the unique challenges faced by small enterprises, this session covers various aspects that directly impact the bottom line. Attendees will learn how to optimize operational efficiency, manage expenses, and increase revenue through innovative marketing and customer engagement techniques.
3.0 Project 2_ Developing My Brand Identity Kit.pptxtanyjahb
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As a business owner in Delaware, staying on top of your tax obligations is paramount, especially with the annual deadline for Delaware Franchise Tax looming on March 1. One such obligation is the annual Delaware Franchise Tax, which serves as a crucial requirement for maintaining your company’s legal standing within the state. While the prospect of handling tax matters may seem daunting, rest assured that the process can be straightforward with the right guidance. In this comprehensive guide, we’ll walk you through the steps of filing your Delaware Franchise Tax and provide insights to help you navigate the process effectively.
Discover the innovative and creative projects that highlight my journey throu...dylandmeas
Discover the innovative and creative projects that highlight my journey through Full Sail University. Below, you’ll find a collection of my work showcasing my skills and expertise in digital marketing, event planning, and media production.
Accpac to QuickBooks Conversion Navigating the Transition with Online Account...PaulBryant58
This article provides a comprehensive guide on how to
effectively manage the convert Accpac to QuickBooks , with a particular focus on utilizing online accounting services to streamline the process.
Enterprise Excellence is Inclusive Excellence.pdfKaiNexus
Enterprise excellence and inclusive excellence are closely linked, and real-world challenges have shown that both are essential to the success of any organization. To achieve enterprise excellence, organizations must focus on improving their operations and processes while creating an inclusive environment that engages everyone. In this interactive session, the facilitator will highlight commonly established business practices and how they limit our ability to engage everyone every day. More importantly, though, participants will likely gain increased awareness of what we can do differently to maximize enterprise excellence through deliberate inclusion.
What is Enterprise Excellence?
Enterprise Excellence is a holistic approach that's aimed at achieving world-class performance across all aspects of the organization.
What might I learn?
A way to engage all in creating Inclusive Excellence. Lessons from the US military and their parallels to the story of Harry Potter. How belt systems and CI teams can destroy inclusive practices. How leadership language invites people to the party. There are three things leaders can do to engage everyone every day: maximizing psychological safety to create environments where folks learn, contribute, and challenge the status quo.
Who might benefit? Anyone and everyone leading folks from the shop floor to top floor.
Dr. William Harvey is a seasoned Operations Leader with extensive experience in chemical processing, manufacturing, and operations management. At Michelman, he currently oversees multiple sites, leading teams in strategic planning and coaching/practicing continuous improvement. William is set to start his eighth year of teaching at the University of Cincinnati where he teaches marketing, finance, and management. William holds various certifications in change management, quality, leadership, operational excellence, team building, and DiSC, among others.
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1. Role of Water in “Man Made Rock” By G Narendra Goud Asst.Manager QA/QC 1
2. Contents Role of Water in Cement Concrete 2 Cement Concrete- the “Man Made Rock” Requirements of water used in concrete Hydration Water/Cement Ratio and Strength Workability of Concrete Admixtures Durability of Concrete Sprayed concrete
3. 1. Cement Concrete-The “Man Made Rock” Role of Water in Cement Concrete 3 Concrete is not just another material, it is 2ndmost used material on the Earth It is a composite material made up of a filler and a binder The binder(cement paste) "glues" the filler together to form a synthetic conglomerate. The constituents used for the binder are Cement and Water, while the filler can be fine and/or coarse aggregate
4. Binder = Cement + Water Role of Water in Cement Concrete 4 Cement consists of Mainly Lime 75 to 77% Silica and Alumina 12 to 15% Iron Oxide 0.5 to 6% Water consists of Hydrogen and Oxygen (i.e. H2O)
5. 2. Requirements of water used in concrete Role of Water in Cement Concrete 5 Water used for mixing and curing shall be clean and free from injurious amounts of Oils, Acids, Alkalis, Salts, Sugar, Organic materials Potable water is generally considered satisfactory for mixing concrete Mixing and curing with sea water shall not be permitted. The pH value shall not be less than 6
6. Role of Water in Cement Concrete 6 2. Requirements of water used in concrete The permissible limits for solids in water Solids Permissible Limits (Max) Organic 200 mg/lit Inorganic 3000 mg/lit Sulphates (SO4) 500 mg/lit Chlorides (Cl) 500 mg/lit Suspended matter 2000 mg/lit What if water does not meet the above requirements????
7. 3. Hydration Role of Water in Cement Concrete 7 Concrete achieves its strength through a chemical process called Hydration. Hydration is a complex process but in simple terms, is the reaction between water and the cement in the mix.
8. 3. Hydration Role of Water in Cement Concrete 8 Stage IHYDROLYSIS of the cement compounds occurs rapidly with a temperature increase of several degrees Stage II is known as the DORMANCY PERIOD. The evolution of heat slows dramatically in this stage. This can last from one to three hours. here concrete is in a plastic state which allows it to transport and place without major difficulty. At the end of this stage initial setting begins In stages III and IV, the concrete starts to HARDEN and the heat evolution increases due primarily to the hydration of tricalcium silicate Stage V is reached after 36 hours. The slow formation of hydrate products occurs and continues as long as water and unhydrated silicates are present.
9. 4. Water/Cement Ratio and Strength Role of Water in Cement Concrete 9 The most important indicator of strength Lower w/c ratio is, the higher the final concrete strength Concept was developed by Duff Abramsof The PCA in the early 1920's
10. Role of Water in Cement Concrete 10 4. Water/Cement Ratio and Strength
11. Role of Water in Cement Concrete 11 4. Water/Cement Ratio and Strength A minimum w/c ratio of about 0.25 by weight is necessary to ensure that the water comes into contact with all cement particles (for complete hydration) Typical values are 0.25 to 0.6
12. Role of Water in Cement Concrete 12 4. Water/Cement Ratio and Strength (w/c) Ratio 0.40 0.50 0.60 0.70 0.80 Probable Strength(%) 100 87 70 55 44 Factors Low w/c ratio High w/c ratio Strength High Low Permeability Low High Shrinkage Low High
13. Adding extra water to concrete!!! Role of Water in Cement Concrete 13 Adding more water creates a diluted paste that is weaker and more susceptible to cracking and shrinkage Shrinkage leads to micro-cracks (zones of weakness) Once the fresh concrete is placed, excess water is squeezed out of paste by weight of aggregate and cement The excess water bleeds out onto the surface. The micro channels and passages that were created inside the concrete to allow that water to flow become weak zones
14. Adding extra water to concrete!!! Role of Water in Cement Concrete 14 This affects the compressive, tensile and flexural strengths, the porosity and the shrinkage Loss of Inherent good qualities like Cohesiveness and Homogeneity Harmful to Strength and Durability Sowing the seed of Cancer in concrete It is an Abuse It is a Criminal act Un-engineering------------------(M.S.Shetty, Eminent Author)
15. Role of Water in Cement Concrete 15 * Increased strength. * Lower permeability. * Increased resistance to weathering. * Better bond between concrete and reinforcement. * Reduced drying shrinkage and cracking. * Less volume change from wetting and drying. Advantages of low water/cement ratio
16. 5. Workability Role of Water in Cement Concrete 16 The ease with which freshly mixed concrete can be transported, placed and finished without segregation Influencing factors Size, Shape, Texture and grading of aggregate Water Content Admixtures Mineral (Fly ash, Silica fume, GGBFS) Chemical Air entraining
17. Admixture types Role of Water in Cement Concrete 17 Chemical and Air-entraining admixtures are Covered by IS:9301-1999 a) Accelerating admixtures b) Retarding Admixtures c) Water-reducing admixtures (plasticizers) d) Air-entraining admixtures and e) Super-plasticizing admixtures
18. Water-reducing admixtures Role of Water in Cement Concrete 18 An admixture which either increases workability of freshly mixed mortar or concrete without increasing water content or maintains workability with a reduced amount of water Role of water reducers is to deflocculate the cement particles agglomerated together and release the water tied up in these agglomerations Can be categorized according to their active ingredients salts and modifications of hydroxylized carboxylic acids (HC type) salts and modifications of lignosulfonic acids and Polymeric materials (PS type) Reduces water demand 7-10% Example:PolyHeed 997 -BASF, FLOCRETE N-Don chemicals
19. Air-entraining admixtures Role of Water in Cement Concrete 19 Which causes air to be incorporated in the form of minute bubbles in the concrete or mortar during mixing, usually to increase workability and resistance to freezing and thawing and disruptive action of de-icing salts Reduces bleeding and segregation of fresh concrete Can be categorized into four groups: salts of wood resins synthetic detergents salts of petroleum acids, fatty and resinous acids and their salts MB-AE 90-BASF, Airalon® 3000-Grace
20. Super-plasticizing admixtures Role of Water in Cement Concrete 20 Which imparts very high workability or allows a large decrease in water content for a given workability Reduce water content by 12 to 30 percent The effect of superplasticizers lasts only 30 to 60 minutes and is followed by a rapid loss in workability Superplasticizers are usually added to concrete at the jobsite Example : Glenium-BASF, Supaflo-Don Chemicals
21. 6. Durability of Concrete Role of Water in Cement Concrete 21 The factors influencing durability include The environment The cover to embedded steel The type and quality of constituent materials The cement content and water/cement ratio Workmanship to obtain full compaction Efficient curing The shape and size of the member
22. 6. Durability of Concrete Role of Water in Cement Concrete 22 Cement content and water/cement ratio For bridges with individual span lengths more than 30 m
23. 6. Durability of Concrete Role of Water in Cement Concrete 23 Minimum Cement content and Maximum water/cement ratio for Culverts and other incidental construction
24. Role of Water in Cement Concrete 24 The minimum cement content is based on 20 mm aggregate For larger size aggregates, it may be reduced up to 10% For underwater concreting, the cement content shall be increased by 10% Severe conditions of exposure shall mean alternate wetting and drying due to sea spray, alternate wetting and drying combined with freezing and buried in soil having corrosive effect. 6. Durability of Concrete
25. Role of Water in Cement Concrete 25 Curing methods 1. Water curing 2. Steam curing 3. Curing compounds Water curing Sea water shall not be used for curing Seawater shall not come into contact with concrete members unless it has attained adequate strength Exposed surface of concrete shall be kept continuously in a damp or wet condition by ponding or by covering with a layer of sacks, canvas, Hessian or similar materials and shall be kept constantly wet for a period of not less than 14 days from the date of placing of concrete. 6. Durability of Concrete- Curing
26. Role of Water in Cement Concrete 26 Curing compounds All concrete cured by this method shall receive two applications of the curing compound The first coat shall be applied immediately after acceptance of concrete finish The second application shall be made after the first application has set Curing compounds shall not be used on any surface which requires further finishing to be applied No curing compound shall be permitted in locations where concrete surfaces are required to be bonded together 6. Durability of Concrete- Curing
27. 7. Sprayed Concrete Role of Water in Cement Concrete 27 “Dry spray” process “wet spray” process
28. Properties and advantages of sprayed concrete over poured concrete Role of Water in Cement Concrete 28 Low Water/Cement Ratio High Strengths with Rapid Strength Gain High Density/Low Permeability Enhanced Adhesion and Bond Strength High Speed High Output Reduction in Formwork Costs Ease of Access
29. TYPICAL APPLICATIONS AND USES New Construction Underground Construction Role of Water in Cement Concrete 29 Shell roofs and domes Retaining walls Piled wall facings Silo structures Barrel vaulting Diaphragm walls Caissons Blast proof structures Bank vaults Tunnel linings Storage reservoirs
30. TYPICAL APPLICATIONS AND USES Water Retaining Structures Protective Coatings Role of Water in Cement Concrete 30 Fire protection to structural steelwork Refractory linings Pipeline encasement Rock and soil stabilisation Sea and river walls Reservoirs and dams Aqueducts Swimming pools Water towers Canal linings Irrigation and drainage channels
31. TYPICAL APPLICATIONS AND USES Strengthening and Repair Free Formed Structures Role of Water in Cement Concrete 31 Concrete damaged by reinforcement corrosion Fire damaged structures Cooling towers Bridges Jetties and wharves Brick arches and tunnels Tunnel linings overlays Swimming pools Landscaping Climbing walls Theme parks Sculpture Water sports slalom courses Bobsleigh runs Zoological structures
33. Role of Water in Cement Concrete 33 TYPICAL APPLICATIONS AND USES
34. References Role of Water in Cement Concrete 34 MORTH IS:456 PLAIN AND REINFORCED CONCRETE-CODE OF PRACTICE IS:9103- CONCRETE ADMIXTURES — SPECIFICATION www.sca.org.uk
35. “Eitheryou’re part of the solution, oryou’re part of the problem.” -Eldridge Cleaver Role of Water in Cement Concrete 35