INTER COLLEGE E-POSTER COMPETITION BY ULTRA TECH (at B.V.M. Engineering College) INSTITUTE:

A. D. PATEL INSTITUTE OF TECHNOLOGY (Civil Engg.) GROUP MEMBERS:

1. Abhal Gudhka2. Kalpesh Bhatti3. Nilesh Balasara4. Satish Patel

HPC & DURABILITY OF

CONCRETE

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

DIFFERENCE

Conventional Mix High Performance Concrete

Generally designed on the basis of compressive strength

It may not meet many functional requirements such as impermeability, resistance to frost, thermal cracking.

Concrete of required performance

Good workability, high durability and high strength are the salient features of HPC.

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

CRITERIA FOR MATERIAL SELECTION &MAJOR FACTOR AFFECTING DURABILITY1. Ease of placement2. Long-term mechanical properties3. Early-age strength4. Toughness5. Life in severe environment6. Volume stability

High permeability• High w/c ratio• Poor grading• Poor compaction• Poor curing

Ingress• Water(sorptivity)• Fluid(permeation)

• Vapour or gas ions(diffusion)

Deterioration• Corrosion• Micro-cracking

Ease in construction

DurabilityMechanical properties

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

METHODS FOR ACHIEVING HIGH PERFORMANCE

Reduced capillary

pores

No fluid movemen

t

Increased physical

resistance

Chemically active binding

sites

Prevents entry of

aggressive ions

Increased physical

resistance

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

DURABILITY OF CONCRETE Durability may be defined as the property

required for fulfilling all the service requirement of a structure during its intended life with the expected maintenance.

Low durability results in cracking, spalling and corrosion.

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

LOW DURABILIT

Y

CrackingShrinkage,

Heat of hydration

Carbonation

Reduction in pH value

Alkali-silica

reactionExpansive

gel formation

Chemical attack

Sulphate attack,

Chloride attack

Physical aggressio

nFreeze-thaw,

Abrasion

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

ADMIXTURES USED FOR BETTER DURABILITY Mineral admixtures:

Silica fume, Fly ash, Ground granulated blast furnace slag: makes denser and stronger concrete

Chemical admixtures: Plasticizers, Super plasticizers: improves

workability Retarders: prolongs initial setting time Air-entraining agents: better workability,

resistance to freeze-thaw action

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

USE OF FLY ASH

FLY ASH

Greater strengthcombines with free

lime

Low permeabilit

y:High

durability

Prevents destructive expansion :

combines with alkali

Less heat of

hydration: prevents thermal cracking

Reduced efflorescen

ceCombines with salts

ECONOMICAL

ECOFRI

ENDLY

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

HOW PLASTICIZER WORKS

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

APPLICATION OF HPC Bridges High rise buildings Marine structures Tunnels Pavements Nuclear Structures

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

CASE STUDY: THE COMPUTER SCIENCE BUILDING AT YORK UNIVERSITY

HVFA Concrete Mix Proportion (kg/m³)MATERIAL TYPICAL MIX

(30 MPa)JOB MIX(25 MPa)

JOB MIX(30 MPa)

Cement 380 150 170Fly ash 0 150 170Stone 1130 1150 1110Sand 716 850 800Water 171 135 135

W/C ratio 0.45 0.40 0.40

HVFA: High Volume Fly Ash• Relatively easy to place and finish• An early-age (plastic) cracking issue during hot

windy weather was addressed through the use of an evaporation retardant.

01/05/2023HPC & DURABILITY OF CONCRETE A.D.I.T

REFERENCE Concrete Technology (Oxford) Optimizing the Use of Fly Ash in Concrete

By: Michael Thomas, Ph.D., P.Eng., Professor of Civil Engineering, University of New Brunswick

Web

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