Admixtures for Concrete - College of · PDF fileAir-entraining admixtures Water-reducing...

Admixtures for Concrete

Admixtures for Concrete

Admixtures Air-entraining admixtures Water-reducing admixtures Plasticizers Accelerating admixtures Retarding admixtures Hydration-control admixtures Corrosion inhibitors Shrinkage reducers ASR inhibitors Coloring admixtures Miscellaneous admixtures

Admixtures for Concrete

Air-Entraining Admixtures

Improve durability in concrete exposed to Freeze-thaw Deicers Sulfates Alkali-reactive environments

Improve workability

ASTM C 260 or AASHTO M 154ASTM C 260 or AASHTO M 154

Admixtures for Concrete

Frost Damage

Admixtures for Concrete

Scaled Concrete Surface

Admixtures for Concrete

Water-Reducing Admixtures

Reduce mixing water required to produce a certain slump

Reduce water-cement ratio Reduce cement content Increase slump

Primarily used to:Primarily used to:

Admixtures for Concrete

Water Reducing Admixtures

Type A ― reduces water content at least 5% tends to retard ― accelerator

often added Type D ―

reduces water content 5% min. retards set

Type E ― reduces water content 5% min. accelerates set

ASTM C 494 or AASHTO M 194ASTM C 494 or AASHTO M 194

Admixtures for Concrete

Water Reducer and Slump Loss

Admixtures for Concrete

Retardation (Initial Set)

Admixtures for Concrete

Retardation (Final Set)

Admixtures for Concrete

Mid-Range Water Reducing Admixtures

Reduce water content 6% to 12%

Reduce cement content Reduce water-cement ratio No retardation Improve placeability and

finishability

Admixtures for Concrete

Admixtures for Concrete

High-Range Water-Reducing Admixtures

Reduce H2O content 12% -30% Reduced W/C produces conc.

with: Compressive Strength > 70 MPa Increased early strength gain Reduced Cl ion penetration

ASTM C 494 or AASHTO M 194 ASTM C 494 or AASHTO M 194

Type F― Water Reducing

Type G ― Water Reducing and Retarding

Admixtures for Concrete

High-Range Water Reducer and Slump Loss

Admixtures for Concrete

HRWR, Water Reducer and Air Loss

0.048825.66.8B0.065593.86.4M0.040714.86.8NHigh-range

water reducer

0.040744.66.2H0.038674.77.0LWater

reducer

0.020563.05.4CControlMixture

Rate of air loss,

%/minute

Percent air

retained

Final air content,

% *

Initial air content,

%

*at point where slump falls below 25 mm

Admixtures for Concrete

Compressive Strength Development

Admixtures for Concrete

Plasticizers for Flowing Concrete

Essentially High-Range Water Reducer

SuperplasticizersAlso known as ―

ASTM C 1017Type 1 ―Plasticizing

Type 2 ― Plasticizing and Retarding

Admixtures for Concrete

Plasticizers for Flowing Concrete

Produce flowing concrete with high slump ( 190 mm [7.5 in.])

Reduce bleeding

Extended-slump-life plasticizer reduces slump loss.

ASTM C 1017ASTM C 1017

Superplasticizers

Admixtures for Concrete

Flowing Concrete

Admixtures for Concrete

Flowing Concrete as Thin Overlay

Admixtures for Concrete

Flowing Concretes and Slump Loss

Admixtures for Concrete

Retardation of Flowing Concrete (Initial Set)

Admixtures for Concrete

Retardation of Flowing Concrete (Final Set)

Admixtures for Concrete

Compressive Strength Development in Flowing Concrete

Admixtures for Concrete

Bleeding of Flowing Concrete

Admixtures for Concrete

Retarding Admixtures

Delay setting or hardening rate for:

Hot-weather concreting Difficult placements Special finishing processes

ASTM C 494 or AASHTO M 194, Type BASTM C 494 or AASHTO M 194, Type B

Admixtures for Concrete

Slump Loss at Various Temperatures

Admixtures for Concrete

Accelerating Admixtures

Accelerate the rate of: Hydration (setting) Early-age strength gain

ASTM C 494 or AASHTO M 194, Type CASTM C 494 or AASHTO M 194, Type C

Calcium chloride accelerators: Increase drying shrinkage,

potential reinforcement corrosion, potential scaling

Darken concrete

Admixtures for Concrete

Maximum Chloride-Ion Content

0.30Other reinforced concrete construction

1.00Reinforced concrete that will be dry or protected from moisture in service

0.15Reinforced concrete ex-posed to chloride in service

0.06Prestressed concreteType of member

Maximum water soluble chloride-ion (CI¯) in

concrete, percent by mass of cement

Admixtures for Concrete

Corrosion Inhibitors

Control Corrosion of Steel Reinforcement

Dosage dependent on anticipated chloride level

Admixtures for Concrete

Shrinkage-Reducing Admixtures

Admixtures for Concrete

ASR Inhibitors—Lithium Carbonate

Admixtures for Concrete

Coloring Admixtures (Pigments)

Admixtures for Concrete

Liquid Admixture Dispenser

Admixtures for Concrete

Videos 1/2

Air-Entraining Admixture Water Reducer

Admixtures for Concrete

Videos 2/2

Retarder/Accelerator Admixture Dispenser