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A SEMINAR PRESENTATION ON “HIGH VOLUME FLY ASH CONCRETE” 2015 PRESENTED TO:- MR. ARVIND SINGH GAUR ASST. PROFESSOR CIVIL DEPT SUBMITTED BY: GAURAV KUMAR GUPTA 11EAYCE037 B. Tech. IV Yr., VIII Sem.
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Application of high volume fly ash concrete

A SEMINAR PRESENTATION ON HIGH VOLUME FLY ASH CONCRETE2015

PRESENTED TO:-MR. ARVIND SINGH GAURASST. PROFESSOR CIVIL DEPT

SUBMITTED BY: GAURAV KUMAR GUPTA 11EAYCE037B. Tech. IV Yr., VIII Sem.

CONTENTSINTRODUCTIONPHYSICAL ASPECTSCHEMICAL COMPOSITION OF FLY ASHPROBLEM IN DISPOSAL OF FLY ASHHEALTH ATTRIBUTESUSES OF FLY ASHWAYS TO USE FLY ASHFLY ASH IN CONCRETEADVANTAGES OF USING FLY ASH IN CONCRETEHIGH VOLUME FLY ASH CONCRETEPROPERTIES OF HVFAC PRODUCT COMPARISONCOMPRESSIVE STRENGTHAPPLICATION OF HVFACHVFAC IDEAL FOR INTERSTATE HIGHWAY SYSTEM AND SECONDARY ROADSHVFAC CHECKLISTCONSTRUCTION PRACTICES AND CURINGCHARACTERISTICS AFFECTING PERFORMANCE OF FLY ASH CONCRETECONCLUSION

WHAT IS FLY ASH?Fly ash is a fine powder produced as a product from industrial plants using pulverized coal or lignite as fuel

transported by the flue gases and collected by the electrostatic precipitator.

They are spherical shaped balls finer than cement particles

The color varies from light to dark grey depending upon its carbon contents.

The quality of fly ash varies from source to source.

fly ash particles are small, they effectively fill voids

PHYSICAL ASPECTSCHEMICAL COMPOSITION of fly ash

MATERIALSPORTLAND CEMENT%FLY ASH%SiO2 21.8253.39Al2O3 6.4916.07Fe2O31.9313.05CaO60.746.33MgO1.085.48SO32.621.06Na2O0.141.59Free Cao0.840.11fly ash are amorphous (glassy) due to rapid cooling; those of cement are crystalline, formed by slower cooling.

Portland cement is rich in lime (CaO) while fly ash is low. Fly ash is high in reactive silicates while Portland cement has smaller amounts

PROBLEM IN DISPOSAL OF FLY ASH In India alone, we produce 75 million tons of fly ash every year, the disposal of which has become a serious environmental problem. The effective use of fly ash in concrete making is therefore attracting serious considerations of concrete technologists and government departments.

HEALTH ATTRIBUTESThere are traces of heavy metals in the fly ash.Some debate that the metals are effectively locked into the cement matrix, preventing their release. By using fly ash in concrete rather than landfilling it, the potential for the metals to leach into the environment is reduced.Concerns have also been raised about the higher incidence of Radium-226 in fly ash

Uses of Fly ash Used in cementFly Ash blended cement (PPC) too is gaining acceptance. The share of Ordinary Portland Cement is projected to decline to 57.9% from 71% by the year 2011.

Used in concrete In concrete it is used normally as main ingredient. Usage ranges from 15% to 60%. e.g.-high volume fly ash concrete (HVFAC)8

WAYS TO USE FLY ASH IN CONCRETEMixing fly ash with cement clinker at the factory to produce Portland Pozzolana Cement (PPC).

Using fly ash as an admixture at the time of making concrete at work site9FLY ASH IN CONCRETE:Fly ash could be an expensive replacement for Portland cement in concrete and using it, improves strength, segregation and ease of pumping concrete.

Fly Ash particles provide a greater workability of the powder portion of the concrete mixture which results in greater workability of the concrete and a lowering of water requirement for the same concrete consistency.

ADVANTAGES OF USING FLY ASH IN CONCRETE

Though fly ash offers environmental advantages it also improves the: performance and quality of concrete. Fly ash affects the plastic properties of concrete by improving workability Reduces water demand Reduces segregation and bleeding.Lowers heat of hydration. Fly ash increases strengthReduces permeability

HIGH VOLUME FLY ASH CONCRETE IS: 456 2000(Code of Practice for Plain and Reinforced Concrete) allows replacement of OPC by Fly ash up to 35% as binding materialHigh volume fly ash concrete is a concrete where a replacement of 50 to 60 percentage of cement is made with the usage of fly ash. Low Water Content.Low Heat of Hydration.Low Cement Content.produce sustainable, high performance concrete mixtures that show high workability, high ultimate strength, and high durability.12PROPERTIES OF HVFA CONCRETEEasier flowability, pumpability, and compactabilitySlower setting timeEarly-strength up to 7 days, which can be accelerated with suitable changes in the mix designMuch later strength gain between 28 days and 90 days or more

Tuesday, March 24, 201513FLY ASH IN CONCRETEProduct ComparisonsHigh Volume Fly Ash ConcreteLess energy intensive manufactureHigher ultimate strengthMore durableUses a waste by-productLess global warming gases createdIs a LEED certified materialConventional ConcreteEnergy intensive manufacturingWeaker ultimate strengthLess durableMore global warming gases created

COMPRESSIVE STRENGTH:Typically, concrete made with fly ash will be slightly lower in strength than straight cement concrete up to 28 days, equal strength at 28 days, and substantially higher strength within a years time. Thus, fly ash concrete achieves significantly higher ultimate strength than can be achieved with conventional concrete.

Strength in terms of days+comparitive analysis btwn class f & class cAPPLICATION OF HIGH VOLUME FLY ASH CONCRETEDam construction( ghatghar dam maharashtra)

Pavement constructionHungry horse dam ,USA built in 1929Rihand irrigation project ,INDIA built in 1962HVFAC: Ideal for the Interstate Highway System and Secondary Roads HVFA is more durable than asphaltic concrete and needs almost no maintenance.The design of a highway pavement is based on flexural strength and HVFA concrete keeps gaining strength with age .There is no reinforcing steel in pavement concrete and roller compacted concrete. Thus the corrosion of steel is a non issues.It increases fuel efficiency of transport trucks by 11%, resulting in cost savings and lower exhaust emissions..HVFA concrete is competitive with asphaltic concrete even onfirst-cost basis

ASPHALT ROADHVFAC Checklist-Fresh ConcreteEnhancing concrete workabilityEase of PumpingImproved FinishingReduced BleedingReduced SegregationHardened ConcreteIncreasing Concrete PerformanceHigher StrengthDecreased PermeabilityIncreased DurabilityReduced Sulfate AttackReduced Heat of Hydration

18CONSTRUCTION PRACTICES AND CURINGHVFAC takes longer time to set. Accelerating admixtures used based on compatibility

HVFAC concrete mixtures do not suffer excessive slump loss in a short period

With slabs, concrete surfaces must be membrane cured or by covering the surface with a heavy plastic sheet

Minimum of 7 days of moist-curing mandatory19Characteristics Affecting Performance of Fly Ash ConcreteFineness - Finer the fly ash, the more the surface area available to react with lime and thus more will be the pozzolanic activity of fly ash.

Calcium (CaO) content Higher the CaO content, the greater will be the pozzolanic activity and greater the contribution to the strength in concrete.20CONCLUSIONSHVFAC provides a good option for recycling of fly ash

Characteristics such as resistance to corrosion, resistance to alkali aggregate reaction, resistance to sulfate attack, durability get incorporated

Longer time required for proper curing

Properties like compressive strength, flexural strength, modulus of elasticity and split tensile strength are improved.

21THANK YOU


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