Chemical Admixture 2

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ustry

Chemical AdmixturesChronology, Classifications and

Effective Usesby

T. P. Banerjee

Head

Training

Need for Indian Concrete InCement superplasticizer interaction in concrete is a complex blend ofchemical and physical mechanisms that are interdependent.

Studies on cement-water reducer interactions in India have beenlimited to the workability evaluation of concretes containing thesechemicals, in specific regions where rapid slump loss has been observed in

concreting operations. There have not been any investigations tounderstand the physico-chemical nature of this interaction. Thus, theresults from these studies are not broad-based, i.e. they apply to a small

group of cements and/or chemical admixtures.

There is a distinct need for the characterization of Indian cement andadmixture properties, in order to understand the nature of theirinteractions. Moreover, the wide range of cements used, varyingtransportation durations and climatic conditions necessitate afundamental study that explains the mechanisms of interaction and helps

establish methods for identifying incompatibility in practical situations.

Explosion of Chemical Admixtures in the


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Twentieth Century with the change in Rheologyof Concrete

Those that disperse cement particles

Those that modify the kinetics of hydrationThose that react with the sub-products of hydration reactions

Those that have only physical action

Normal Plastic

Concrete

Fluid

Concrete

Self Consolidated

Concrete

Development in AdmixturesConcrete

performance

Mega-

plasticizer

Super-

plasticizer

Plasticizer

Different types ofVEAs

Polycarboxylates

Poly Acrylates

Naphthalene Sulphonates

Melamine Sulphonates

Lignosulphonates

1950 1970 1980 1990 2000

Plastic

concrete

Rheoplastic

concrete

Self compacting

concrete


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ADMIXTURES

As per BIS 9103

An Admixture is defined as a material other than water,

aggregates, hydraulic cement and additives like pozzolana

or slag and fibre reinforcement used as an ingredient of

concrete or mortar, and added to the batch immediately

before or during its mixing to modify one or more properties

of concrete in the plastic or hardened state.

Advantages of using ChemicalAdmixtures

The purpose of using chemical admixtures is to modify certain properties ofmortar, concrete or grout.

In the fresh / plastic state:

To increase workability without increasing water content

To reduce water content (5 40%) without changing the workability To accelerate or retard the initial setting time

To reduce or prevent settlement / to create slight expansion

To arrest / reduce bleeding

To reduce segregation & increase cohesiveness

To improve pumpability

To reduce slump loss / modify slump retention time

To improve finishability

Also to entrain air in concrete for specific purposes

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Advantages of using Chemical

Admixtures

And in the hardened state

To accelerate rate of strength development at early ages

To retard or reduce rate of heat evolution during early hydration of

cement

To increase physical strengths (compressive, tensile or flexural)

To increase durability by decrease in permeability

To reduce expansion due to alkali-aggregate reaction

To counterfreeze & thawphenomenon

To reduce scaling caused by deicing salts

Advantages of using ChemicalAdmixtures

And in the hardened state (Contd)

To increase bond to steel reinforcement and between existing and new

concrete

To improve impact resistance and abrasion resistance

To inhibit corrosion of embedded metal

To produce coloured concrete or mortar

To reduce drying shrinkage

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Types of Chemical AdmixturesGeneral Admixtures

Plasticizer

Superplasticizer

Retarder

Accelerator

Retarder cum water reducer

Accelerator cum water reducer

Air Entraining Compound

Special Purpose Admixtures

Corrosion Inhibiting Admixture Anti wash-out Admixture Gas Forming Admixtures

Grouting Admixtures

Shotcrete Admixtures Extended et Control Admixtures (Surface Retarders) Pumping Aids / Flocculating Admixtures Bonding Admixtures Colouring Admixtures

Fungicidal Germicidal Insecticidal Admixtures Permeability Reducing Admixtures

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ASTM C 494 1999

AASHTO M 194TYPEA : Water Reducing

TYPE B : Retarder

TYPE C : Accelerator

TYPE D : Water Reducer cum Retarder

TYPE E : Accelerator cum Water Reducer

TYPE F : High Range Water Reducer

TYPE G : High Range Water Reducer cum Retarder

BIS 9103 1999 (Reaffirmed 2007)

TYPEA : Water Reducer

TYPE B : Retarder

TYPE C : Accelerator

TYPE D : Air EntrainerTYPE E : High Range Water Reducer

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ASTM C 260 and AASHTO M 154Air Entraining Admixture

ASTM D 98 and AASHTO M 144

Accelerating Admixtures Calcium Chloride

ASTM C 1017Admixtures for producing Flowing Concrete

Air Entraining AdmixturesAs per BIS 9103 ACI 116 R

Air-entraining admixture is defined as an admixture for concrete or

mortar which causes air to be incorporated in the form of minute bubbles

in concrete or mortar during mixing usually to increase workability andresistance to freezing and thawing and disruptive action of de-icing salts

The entrained air void system is distinct from air voids physically

entrapped in concrete during placement and consolidation.

These Admixtures are useful for :

Freeze & Thaw Effect

Cohesive Concrete

Arresting Bleeding

Making Movement of Higher Sized Coarse Aggregate

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Air Entraining Admixtures

Air-entraining admixture usually reduces the compressive strength of

hardened concrete, particularly in concretes with moderate to highcementitious material contents. The reduction is normally 5% for eachpercent of air entrained.

But the at the same time, entrained air reduces the total water content

required to maintain a specific slump. The resulting water cementitiousmaterial ratio (w/cm) partially offsets the reduction in strength. This

proves to be true in case of using air-entraining admixtures for lean mass

concretes or concretes with higher size aggregates.

Standard Methods of measuring air content in concrete

The Gravimetric Method (ASTM C 138)

The Volumetric Method ( ASTM C 173)

The Pressure Method (ASTM C 231)

AcceleratorsAs per BIS 9013 and ACI 116 R

An accelerating admixture is defined as an admixture when added to concrete,

mortar or grout increases the rate of hydration of the hydraulic cement,

shortens the time of set or increases the rate of hardening or strengthdevelopment.

Though Calcium Chloride is the most efficient and economical accelerator; but

its uses are reduced in RCC structures as the free chlorides stay strongly with C-

S-H phase in a chemisorbed or interlayer positions. Chloride free accelerating

admixtures like Calcium Formate and others are widely used now-a-days.

Calcium Formate increases the formation of ettringite at ordinary temperatures

accelerating the hydration of the C3S surface.

Accelerators are normally used for cold weather concreting (Not antifreezeAdmixture no depression in the freezing point of water).In tropical atmospheres, they help in :

1. Earlier de-shuttering

2. Earlier handling of pre-cast concrete

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RetardersAs per BIS 9013 and ACI 116 R

Retarding admixtures are defined as the materials which delay the setting time ofcement paste and hence of mixtures, such as mortar or concrete containingcement.

Retarders are absorbed on C3S phase of cement forming a film around cement and

preventing or reducing its reaction with water. This film breaks with time.

Retarders are useful when concreting in hot weather, when normal setting time is

shortened by the higher temperature, and in preventing the formation of

cold joints between successive lifts in concreting.

Precautions

Dosage of retarders are very sensitive extra dosage than recommendedspecifications lead to a very extended set retardation sometimes no setting

at all.

Water Reducing Admixtures(Plasticizers)

As per BIS 9013 and ACI 116 R

A water reducing admixture is defined as an admixture which either increases

workability of freshly mixed mortar or concrete without increasing watercontent or maitains workability with a reduced amount ofwater.

So, if concrete is being for a particular workability (slump value), the additionof a water reducing admixture can give these advantages:

1. Higher compressive strength with less water addition.

2. Compressive strength in concrete can be increased without any additional

cement.

3. Cement content can be reduced, but the target strength can be achieved

with desired workability (Commercial and Environment friendly)

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Admixtures for Flowing Concrete Super Plasticizers (SPs)

ASTM C 1017 defines flowing concrete as concrete that ischaracterized as having a slump greater than 190 mm (7.5 inch) whilemaintaining a cohesive nature

Such Flowing Concretes are only achievable through the use ofadmixtures known as High-Range Water Reducers (HRWR) orSuperplasticisers which enable to reduce water significantly up to 20 to40%. These admixtures conform to ASTM C 494 Type F and Type G;BIS 9103 Type E and also meet the requirements of ASTM C 1017 Type

1 or Type 2 respectively.

As per BIS 9013

A Super plasticizer is defined as an admixture for mortar or concrete

which imparts very high workability or allows a large decrease in

water content for a given workability

Normal Water ReducingAdmixtures

Normal WRAs /plasticisers are based on various chemical

compounds:

1. Lignosulphonate salts of Sodium and Calcium

2. Hydroxycarboxylic acids (Citric and Gluconic acid)

3. Carbohydrates (Corn syrup and Dextrin)

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Types of Superplasticizers

Super plasticisers are based on 5 types of chemical compounds:

1. Modified Ligno Sulphonates (MLS)

2. Sulphonated Melamine Formaldehyde Condensate (SMF)

3. Sulphonated Naphthalene Formaldehyde Condensate (BNS / SNF)

4. Poly Acrylate (AP)

5. Poly Carboxylated Ether (PCE)

CementParticles

Entrappedwater

ElectrostaticRepulsion

(for sulphonatedpolymers)

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Electrostatic and Steric Repulsion

(for acrylic and polycarboxylate polymers)

Comparative Analysis on Action of SPs

Electrostatic repulsion depends on the composition of the solutionphase and the adsorbed amount of the SP ; greater the adsorption,

better the repulsion. [Nakajima and Yamada, 2004].

On the other hand, steric repulsion depends on the length ofmain

chain, length and number of side chains [Sugiyama et al., 2003].

In the case of PCE based admixtures, for fluidity retention, themain chain should be short, with large numbers of long side chains

[Sugiyama et al., 2003]. Because of the steric repulsion mechanism,

PCEs are generally more effective than the sulphonate based

admixtures, and generally do not experience much problems at low

water to cement ratios. However, they are more sensitive to

overdosing and can lead to problems like excessive air entrainment

and retardation.

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SPECIAL ADMIXTURES

Corrosion Inhibitors

Corrosion Inhibitors are added to the reinforced cement

concrete to delay corrosion of the steel.

Corrosion Inhibitors can be broadly classified under

three classes:

1. Anodic Inhibitors

2. Cathodic Inhibitors

3. Mixed Inhibitors

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Corrosion Inhibitors

Effects on Concrete

Fresh Stage: Increase in workability

Setting Stage: Accelerate initial and final set

Hardening Stage:

1. Increase compressive strength

2. Slight decrease the bond strength between steel and concrete

Hardened Stage:

1. Probable increase in alkali-aggregate reactions in presence ofreactive aggregates

2. May increase efflorescence

Anti-washout AdmixturesThese admixtures are used for underwater concreting reducing segregation by

increased cohesiveness.

The concrete admixed with such compounds shows high cohesiveness compared to ordinary

concrete increasing the viscosity of water. As a result, when such a concrete is placed orpoured under the water by a free fall, it does not segregate. The resistance to segregation

depends mainly on the dosage and molecular weight of the admixture.

Application Areas

Foundation of bridge piers in water and slabs.Piled piers, breakwaters of portsProtection of river bedsConcrete for reinforcing rubblestone of backwaters etc.Testing of Effectiveness (Falling through Water Test)

3 litres of concrete are allowed to fall through water in a container of 30 cm diameter and 50

cm height. The pH value and turbidity of the water near the surface are measured after 60

seconds.

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Gas Forming AdmixturesThey generate or liberate bubbles of gas in the fresh mixture during

the hydration process before the initial set of the cement paste matrix

takes place. Generally four types of GFAs are used depending on the typeof gas (Hydrogen, Oxygen , Nitrogen or Air) produced.

Areas of Applications

Grouts , Mortars or Concretes with controlled expansion

To control settlement and bleeding causing the concrete to retain its

initial volume

Intrusion Grouts or Mortars for preplaced aggregate concrete

To improve the intrusion of grouts and mortars in preplaced aggregate

concrete by producing a positive expansion to the extent of 5 to 10%

Cellular Concrete

To produce aerated lightweight concrete and mortar when used at

higher addition rates

Other Grouting Admixtures

These admixtures exhibit special properties to the grout

1. To impart extreme fluidity without any segregation to the grout

2. To keep the pumpable ability of geotechnical cement grouts (ACI

552) and oil-well cementing grouts over large distances under high

temperatures and pressures

3. To resist fast drying and loss of water through adsorption by the

substrate and the tiles in case of bonding and joint filling grouts

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es

es

Shotcrete AdmixturThese admixtures are also called Quick Accelerators or Stiffening Admixtures as

they accelerate the stiffening process in fresh concrete.

These admixtures contribute special requirements in the shotcreting process :

1. Impart fast stiffening makes possible the spraying of concrete on vertical andoverhead surfaces

2. Help to build up thick layers

3. Reduce rebound loss

They may also be in applications for rapid setting and early strength

development like sealing of leaks in below-grade structures, patchwork

and emergency repairs.

Mechanism of Action

Accelerate the reaction between C3A and gypsum forming larger quantities of

ettiringite at early age. Sometimes the rapid reaction of C3A disturbs

the harmonious reaction between the calcium silicates and water.

Shotcrete AdmixturTypes of Shotcrete Admixtures

Shotcrete Admixtures are available in two forms Powder and Liquid.Powder admixtures are used for dry shotcreting and liquid for wet shotcreting.

Dosage

Powder admixtures are used normally at addition rates 2 to 10 % by weight of cement.(Checking the moisture content of aggregate is vital to have a better performance)

Liquid admixtures are usually batched by volume ratios, with the admixture :water ratios ranging from 1:1 to 1:20. then the mix shold be accurately dispensed by

positive flow pumps into the gauge water to have a good overall distribution.

General Specifications

The initial and final set sold occur within 3 and 12 minutes respectively.

Rate of strength development : 4 MPa in 8 hours and 10 MPa in 24 hours (May vary with

specific site requirements

The decrease in strength at 28 days should be less than 30% compared to concrete

without any admixture.

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ixtures

Extended Set Control Admixtures(Surface Retarders)

These admixtures are used to stop or severely retard the cement hydrationprocess in unhardened concretes. They should be added and thoroughly mixedwith the unhardened concrete (either freshly batched or returned) before the

concrete approaches its initial setting time.

Extended set control admixtures differ from the conventional set controlling

admixtures as they stop the hydration process of both the silicate and

aluminate phases in Portland cement while the conventional act only on the

silicate phases.

Applications

1. Creating anchor aggregate finish at construction or segmental joints

2. Disposal of residual unhardened concrete from transit mixer drums / tippers

Examples : Carboxylic Acids and Phosphorus containing organic acids and salts

Pumping Aids / Flocculating AdmThese admixtures are used to enhance the pumpability of Concrete.

Fresh concrete for pumping must be sufficiently mobile, cohesive(no segregation) and capable of flowing with reduced friction along the pipe

walls. Pumping Aids act by physical means imparting lubrication to the freshconcrete increasing its cohesiveness and reducing bleeding in low cement

mixes.

Such admixtures normally contain highly charged groups in their chains

and absorbed on cement particles, linking them together. The net result is

to an increase in inter-particle attraction, which increases the tendency of thepaste to behave as one large floc.

Dosage

Dosage varies with types of polymers used as pumping aids. Normally 0.02% to

1.5% by weight of cement are used.

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Permeability Reducing Admixtures

BIS 2645 - 2003

Permeability reducing admixtures delay the ingress of moisture whenthe concrete is subjected to short or intermittent exposure to rain.

Adding these admixtures actually reduces the rate of water inflowthrough the capillary pores in the concrete delaying the process ofdamage.

Examples: Soaps, Butyl Stearate and certain petroleum products

Admixture Selection by Application

Congested reinforcement

Difficult to ensure compactness of concreteSuperplasticizers increase the workability and flow.Viscosity modifying admixtures prevent segregation.

Early removal of formwork

Rapid strength gain is needed.Superplasticizers can be used to decrease w/c leading to

higher early strength.

Accelerators may be necessary, especially in colderclimates.

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Flooring concrete

Concrete floors require mix to be easy to place and minimalshrinkage.

Plasticizers should be non-retarding.Accelerators may be necessary, especially in colder climates.Shrinkage reducing admixtures will be helpful

High strength concrete

Superplasticizers essential to overcome cohesiveness due tolow w/c and high binder content.


Hot-weather concreting

High temperatures lead to rapid workability loss and quicksetting.

Retarding and plasticizing admixtures help. Marine concrete

Superplasticizers essential to limit permeability.Corrosion inhibiting admixtures increase the corrosion

threshold of the steel.

Anti-washout admixtures for placing concrete under water.

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Pumped concrete

Pumping aids increase the cohesion in the concrete andprevent segregation.

Shotcrete

Plasticizing admixtures are used to get high strength and flow.Set-accelerating admixture is added at the nozzle to so that

the concrete sets rapidly as it hits the substrate.

Performance Requirements as per

BIS 9103 - 1999

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PATIBILITY

Uniformity Tests and Requirements (Table 2)

Sr.

No.

Property Requirement Reference

1 Dry material contenta) For liquid admixture

b) For solid admixture

0.95T DMC < 1.05T,where

T = Manufacturersstated value (percentby mass)

DMC = Test results (percent by mass)

2 Ash content 0.95T AC < 1.05T,where

T = Manufacturersstated value (percentby mass)

AC = Test results (percent by mass)

3 Relative density Within 0.02 of the value stated by manufacturer

4 Chloride ion content Within 10% of the value or within 0.2 % whicheveris greater as stated by the manufacturer

5 pH 6 (Minimum)

CEMENT

SUPERPLASTICIZER INCO

The use of SPs has become very common in India. There has also been a proliferation inthe number of brands of cement, and in the types of cement available.

It is very difficult to ensure that an admixture that produces all the desired effects withcement A would do the same with cement B.

Users often suffer when the supply of cement and/or admixture is changed midwaythrough a project. Problems arising out of compatibility issues are often mistakenfor problems with concrete mixture design by practising engineers.

It must be noted that in such cases, neither the cement nor the admixture is responsible

for such a result. This is an internationally acknowledged fact, referred asIncompatibility of Materials.

So far as material science is concerned, some cements are not compatible with certainadmixtures and vice versa.

Leading researchers have recognized the need to review the acceptance standardsfor both cements and superplasticizers since the incompatibility problems areexpected to grow with further and more extensive use of high performance concrete[Tagnit-Hamou et al., 1992], and also with the number of cements and chemicals availablein the market.

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Common Problems due toIncompatibility

Flash Setting

Delayed Setting

Rapid Slump Loss

Improper Strength Gain

Inordinate Cracking

These issues in turn affect the hardened properties ofconcrete,primarily strength and durability.

Complexity of Superplasiticized Concrete System

On the one hand, there is thecomposition of the SPs ; on the other endof the spectrum is the composition ofcement (Clinker) - particularly therelative proportions of C

3A, alkalis and

C3S in the cement and in addition,

the type of gypsum available (gypsum,hemihydrate or anhydrite) has animportant role to play.

The fineness of cement could also affect

its compatibility with a particularadmixture.

Each of these factors influencesthe phenomenology of cement-waterreducer interaction.

Incompatibility could also arise as a resultof the use of additional mineral additives,or while using multiple chemicals [Bedardand Mailvaganam, 2006].

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Effect of Cement on Incompatibility

1. Content of C3A (controlled by C3A to SO3 ratio)

2. Availability of Calcium Sulphate in the hydrated cement phase

depending on quality of Gypsum added during grinding (whether

Dihydrate (CaSO4.2H20) / Hemihydrate ( CaSO4.1/2 H2O) /Anhydrite

(CaSO4)

3. Alkali content and Type of Alkali present in Cement

4. Process of grinding and Fineness of Cement

And so on.

Admixture Factors for Incompatibility

Admixture

1. Admixture Type and Dosage

2. Higher concentration of reducible sugar

3. Absence of moderate to higher molecular weight chain fractions in

the polymer4. Reduced chain length

5. Unstable elementary composition

6. Location of functional groups in the molecule

7. Time of addition of SP in concrete

And so on.

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atibilityOther Factors for Incomp

1. Low W/ C ratio in the concrete mix resulting lower interparticle separation

of the cement particles makes it more sensitive to loss of water by

evaporation or reaction with cement during transportation of the concrete.

2. Interaction between a superplasticizer and the fines of the sand leading to a

high loss of workability during transportation and early-age

cracking increases even when the concrete is of better quality (which can

occur when fillers absorb the bleed water, causing higher plastic

shrinkage, or when a high paste content causes excessive thermal

shrinkage). The fines content in river sand affects the performance of SPs

[Papayianni et al., 2005].3. The placing of concrete at high ambient temperatures causes increase

in reactivity of C3A which causes higher ettringite contents with

fine morphology in the presence of SP [Greisser, 2002 ; Spiratos et al.,

2003],

thus causing a higher rate of slump loss.

GUIDELINES FOR CHOOSING

COMPATIBLE COMBINATIONS OFCEMENT & SUPERPLASTICIZER

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of the

Marshconeflow

time

Fluidity

MARSH CONE

MARSH CONE test is very useful for checking compatibility ofadmixtures against cements at site level.

With a MARSH CONE, the flow time values of cement paste

with varying dosages of admixtures can be plotted on a

graph. The X-axis will represent DOSAGE and Y-axis will

represent FLOW TIME. The site engineer can study the

graphs plotted with varying dosage of different admixtures

using the same cement and vice versa. The lowest point in

the graph will indicate the best suitable combination of

cement and admixture.

MarshCone Test: Evaluationcompatibility and dosage

800-1000 ml

15.5 cm

29 cm

6 cm

Diameter: 8 mm

200-500 ml

SATURATION

POINT

% sp/c

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Paste-Concrete Correlation

Can the flow behaviour of paste and

concrete be correlated?

Can the paste be used to optimise theconcrete mix?

Cement-Superplasticizer Checklist

Step 1: Study of Paste Characteristics (1/3)

Record the basic properties of cement and

superplasticizer for the quality checks, as well as for

comparing different batches of products.

The Hobart mixer or a similar intensive mixer isessential for the preparation of the paste in order for it

to represent the paste within concrete.

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First criterion: A well-defined saturation dosage fromthe Marsh cone test that is within the maximum dosage

of the superplasticizer recommended by the supplier.

The dosage obtained from the paste tests can be used as

the guideline for selecting the dosage of

superplasticizer for concrete.



Second criterion: The influence of superplasticizer onthe setting behaviour of the paste is checked.

Here, the final setting time of paste is limited to 16

hours as obtained in the Vicat penetration test. If this

criterion is satisfied, the final setting time of concrete

would be not more than 12 hours.

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Step 2: Study of Concrete Characteristics (1/2)

Tests done on concrete to ensure a mix with the

required slump.

Superplasticizer dosage may be increased if the

saturation dosage is not sufficient; however, it is

recommended that the dosage is not more than 150% of

the saturation dosage in order to limit the retardation

and possible segregation, as well as cost.


Step 2: Study of Concrete Characteristics (2/2)

From the point of view of productivity, a minimum value

of 50% of the 28-day compressive strength is

recommended at 3 days (when the early age strength is

critical).

The final choice of the superplasticizer can be based on

the minimum cost considering the dosage of the

superplasticizer for obtaining the desired slump among

the compatible combinations.

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THANK

S

Contact : 9930650145Email : [email protected]

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mailto:[email protected]:[email protected]:[email protected]


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Polymeric Materials for GeneralBuilding Repair

Mr. T. P. Banerjee

HeadTraining

Present Scenario

More than 85% of the concrete produced in India is still by volume batching.There is lack of control of W/C ratio at sites. The control on quality of sandand aggregate is very limited. The concrete usually has high porosity.

In the foundation concrete there is ingress of salts and water. This causesdeterioration of concrete and also the ground water rises in the walls throughthe capillaries in mortar and bricks. This leads to persistent rising dampnessand peeling of paints in walls at the ground level. The life of such structures isnaturally reduced.

The pollutants like CO2 etc. along with water enter into the concrete aboveground leading to corrosion and deterioration of concrete.

The Mortar and Plaster is site mixed cement and sand unlike pre-mix mortarsin other countries. It has lack of adhesion and cohesive propertiescompared to international practice. This leads to cracks in Mortar and Plaster.

All the above lead to cracks and dampness in structures. Hence, the life ofstructures is lower than the designed life.


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Cracks leading to ......

Leakage

Carbonation

Corrosion

Spalling of concrete

Damage of structure

Ultimately lead to collapse

Planning of Repairs Important Steps

Inspection

Diagnosis

Report

Selection of Materials

Job Specification

Methodology

Execution

Post Care


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Why Repairs Fail ?

Improper surface preparation

Improper mixing of repair mortars

Improper use of bonding agents

Wrong application method

Hot & humid climate

Partial repairs

Corrosion starts again

Cracks at the interface of repairs

Other Focus Areas

An opinion from expert consultants and structural audit, ifnecessary

Selection of certified repair contractor

Selection of reputed manufacturer for materials

Supervision during execution

Financial planning


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Inspection of Crack Types


Structural / Non Structural


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Live / Dormant

Ascertaining the width of the crack


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Ascertaining the Depth of the Crack

Detailed inspection, diagnosis is the crux of thematter and if the job specification is technical andholistic, repairs will last longer

Otherwisethe structure will come back to the original state

quickly after repairs and will call for re repairs.


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Repair Materials must offer ..

Compatibility With Old Concrete Excellent Bonding Properties

Low Shrinkage

Good Strength

Dimension Stability

Crack Resistance

Impermeability

Ease of Application

Durability


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MCI TREATMENT

Repair Materials for Specific ApplicationsRebar Treatment

Rust removers / Rust converters Dr. Fixit Rust Remover

Zinc rich epoxy primers Dr. Fixit Epoxy Zinc Primer

Bonding agents

SBR Base (Internal Areas) Dr. Fixit Super LatexAcrylic Copolymer Base (External Surfaces) Dr. Fixit MPBEpoxy Resin Base (Old to New Concrete) Dr. Fixit Concrete Super Bond

Crack Filling

Acrylic paste (cracks below 5 mm)

Dr. Fixit Crack - X Paste/ Dr. Fixit Crack - XPowder

Shrink free polymer filling compound (5 10 mm)

Dr. Fixit Crack - X Shrinkfree

Polymer modified cement systems (> 10 mm)

Dr. Fixit Polymer Mortar HB / Dr. Fixit Magic Mortar


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Repair Materials for Specific Applications

Anchoring

High strength polyester resin anchor grouts Dr. Fixit Anchor FixWater insensitive epoxy anchor grouts for underwater applications

Injection Grouts

Cementitious Pagel Anchor and Injection GroutLow viscous epoxy Dr. Fixit Epoxy Injection GroutPolyurethane Dr. Fixit PU Injection 1403

Repair Materials for Specific WP Applications

Protective Coatings

Primer and Bond Coatings (as pore sealers)Silane Siloxane (water repellents for external walls)Elastomeric acrylic coatings (external walls)Aliphatic acrylic (anti carbonation)Water based epoxy (damp walls)


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Dr. Fixit Raincoat - Unique Product toProvideExternal Wall WP

Heavy duty, waterproof coat for external walls

Twice the thickness at a slight extra cost (120Microns vs 60 Microns)

Bridges cracks up to 0.5 mm width

Highly durable, retains a fresh look and has asuperior sheen

No water dilution at site

Higher binding property & more durability

UV and stain resistant,

Anti-algae, anti-fungal, Low dirt pickup

Anti Carbonation CoatingDr. Fixit Concrete Guard

These coatings are aimed at protecting cementious substratessuch as concrete and plasters.

Generally pure aliphatic acrylic based resisting UV attack

Allow moisture to escape from within to the outside

Elastomeric to withstand small expansion and contractionmovements in the substrate


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Treatment for Dampness Dr. Fixit Dampguard

Water based epoxy breathable coatings (internal damp walls)

Other Treatments for Dampness

Siliconate injection grouts (rising water dampness) Dr. Fixit Dampfree

Crystalline materials (internal pore fillers) Dr. Fixit Krystalline

Polyurethane foam injection (water percolation blockers)Dr. Fixit PU Injection Foam Series


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Repair Materials for Specific WP Applications

Liquid Applied Barrier Systems

Polymer modified cementitious systemsFibre incorporated water based acrylicsPolymer modified bitumen coatings

Weather Protective Liquid Membrane

Dr. Fixit New CoatRe-waterproof existing waterproofing systems like brick bat coba etc without

breaking

Allows foot traffic

Bridges cracks upto 2 mm wide

Ready to use, easy application

Excellent UV resistance


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Innovative waterproofing systems with Dr Fixit Newcoat fornew as well as old roofs

Refurbishment of existing roof usingDr Fixit Newcoat - 7 year life expectancy

New pitched roof waterproofing usingDr Fixit Newcoat - 7 year life expectancy

Application of Dr. Fixit New Coat onManglorian Roof Tiles


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Repair Materials for Specific Applications

Sealants for Dynamic Cracks and Mechanical Loads

Polysulphide Polyurethane Epoxy

Sealants for Joints and Gap Filling

Polysulphide (expansion joint) Polyurethane (expansion joints)

Silicone (door / window frame joints) Acrylic (gap filling in tiles / basins / bath tubs etc.)

Sealing of Cracks by Sealants

Normally cracks which are dynamic ones are filled withsealants.

A groove of minimum 6 mm x 6 mm or maximum 10mm x10mm is prepared by cutting with concrete cutting machine.

The surface preparation and application are carried out as perspecifications and manufacturers guidelines.

In this case of application, backup materials and bond breakersare not used.


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Polymer Composites

Composites

Polymer Concrete(PC)

PolymerModified

Concrete (PMC)

PolymerImpregnated

Concrete (PIC)

Fibre Reinforced Polymer Modified Concrete

Prime Objective

To overcome the intrinsic problems of low ductility, highbrittleness and strong cracking propensity of normal RCC

Comparative Properties of PolymerComposites


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Micro Concrete

Flowable Mortar for repairs to damaged reinforced concretemembers

Free flow and Self compacting

High early & final strength (55 Mpa @ 28 days)

Non shrinking,

Impermeable surface finish

Highly Durable

Can be pumped

RCC beam ready for Microconcrete jacket


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Pour MICRO CONCRETE under gravity

MICRO CONCRETE application under Pressure


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Repaired and Cast with Micro

Concrete

Retrofitting / Structural Strengthening

Fibre Composite Wrapping Systems


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Fiber Composite Materials

Fiber phase Filler Matrix phase

Carbon

Glass Aramid BoronResin

High tensile strength(1860-7070 MPa)High cost

E-Glass S-Glass Kevlar Thermoset Thermoplast

Strength (3400 MPa)Most popularLess cost

Strength(4500 MPa)High cost

Highly cross linked

Non recyclablee.g. Epoxy,

Polyurethane

Not cross linked

Recyclablee.g. Polyester

Advantages of FRP Composites

No corrosion

Higher ultimate strength

Higher elastic modulus

Very good fatigue properties

Low weight - No increased dead weight

No increase in cross-sectional area

Highly flexible composite rolls can take any complex shape

Clean application

Joint free with Endless tapes


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Hence, plethora of materials are available and

todays polymer science brings new dimension to

the construction industry.

But evaluat io n and selectio n of specific

materials for specific areas with systematic

approach is the key to the success of any repair

job

Selection of Crack RepairSystem


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Specialized Courses

Offered by

A Not-for-profit Knowledge Centre

Distance Education (Correspondence) Course(For Professionals / Engineers)One Year Graduate Programme

Concrete Technology, Waterproofing and Repair Management

Certification by : NICMAR and Dr. Fixit Institute

Eligibility

Diploma or Bachelors degree in any branch of Civil Engineering, Mechanical Engineering,Chemical Engineering, Architecture, Town Planning, Building Sciences from a recognizedUniversity.

How to Apply

Prospectus and Application Form can be obtained from NICMAR on payment of Rs. 1103 byDemand Draft or downloaded from websites: www.nicmar.ac.in or www.drfixitinstitute.comand sent along with photocopies of required documents & application fee of Rs. 1000 byDemand Draft to NICMAR. The Demand Draft shall be in favour ofNICMARSODEat Pune.
http://www.nicmar.ac.in/http://www.drfixitinstitute.com/http://www.drfixitinstitute.com/http://www.nicmar.ac.in/


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Certificate Course on Entrepreneurship(For Contractors / Aspiring Students - Entrepreneurs)

Dr. Fixit Institute is organizing certificate courses on specific module on

Entrepreneurship in Waterproofing & Repair Technologies forConcrete Structures

Modules

Ten Day Module : For Contractors

Six Months Module : For Students from ITI and 10+2 Building Maintenance Courses

THANK YOU

Tirtha Pratim BanerjeeMob: 9930650145

Email: [email protected]
mailto:[email protected]:[email protected]:[email protected]

Documents

Chemical Admixture 2