Concrete Products
Technical Guide Specification
Admixtures For Concrete
SECTION 03300
PART I GENERAL
1.01Concrete AdmixturesDefinition
1.02Related Sections
1.03ReferencesACI and ASTM
1.04DefinitionsWater-to-Cementitious Ratio
Corrosion Inhibitor
Microsilica Concrete
Cementitious Materials
1.05Submittals
1.06Delivery and Storage
PART II PRODUCTS
2.01ManufacturersCriteria
2.02MaterialsAdmixtures
A. Air Entraining Agents
B. Water Reducers
C. Retarders
D. High Range Water Reducers
E. Accelerators
F. Corrosion Inhibitor
G. Microsilica
H. Dampproofer
I. Synthetic Fibers
J. Controlled Low Strength Material Additive
2.03Concrete MixesA. Mix Design
B. Proportions
C. Chloride Limits
D. High Range Water Reducers
E. Corrosion Inhibitor
F. Microsilica Concrete
G. Fiber Reinforcement for Concrete
H. Dampproofing Concrete
I. Controlled Low Strength Material
J. Crack-Resistant Concrete Finishing System
PART III EXECUTION
3.01Admixture Manufacturer's Field Service
A. General
B. Preconstruction Job Meetings and Trial Mixtures for
Concrete Containing Corrosion Inhibitor, Microsilica
and High Range Water Reducers
3.02Admixture Addition on Job Site
3.03Environmental ConditionsHot Weather Concreting
Cold Weather Concreting
3.04Finishing and Curing(Notably Corrosion Inhibitor, Microsilica
and High Range Water Reduced Concretes)
ADMIXTURES FOR CONCRETESECTION 03300
Concrete Products
Technical Guide Specification
Admixtures For Concrete
SECTION 03300
PART IGENERAL
1.01Concrete Admixtures
Definition - all materials other than cement, water, and aggregates used as an ingredient of concrete or mortar, which are added during mixing cycle.
1.02Related Sections
NTSFor projects requiring special admixture needs and for contractors who are first-time users of high range water reducers, non-chloride accelerators, microsilica concrete and corrosion inhibitors, preconstruction conference, Section 3.01B and concrete finishing and curing recommendations, Section 3.04 should be followed. W. R. Grace & Co.-Conn. admixture specialists are available to assist in the writing of additional sections to assure proper knowledge of product behavior prior to project start-up.
A.Section 01200 - Preconstruction Meetings
B.Section 03345 - Concrete Finishing
1.03References
A.ACI - 211.1 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete.
B.ASTM C 260 Standard Specification for Air-Entraining Admixtures for Concrete.
C.ACI - 302.1 Guide for Concrete Floor and Slab Construction.
D.ACI - 305R Hot Weather Concreting.
E.ACI - 306R Cold Weather Concreting.
F.ACI - 308 Standard Practice for Curing Concrete.
G.ACI - 318 Building Code Requirements for Reinforced Concrete.
H.ASTM C 494 Standard Specification for Chemical Admixtures for Concrete.
I.CSA 266
1.04Definitions
A.Water-to-Cementitious ratio - An equational value representing quantity in pounds of free moisture available for cement hydration divided by quantity of cementitious materials in pounds per cubic yard concrete.
B.Corrosion Inhibitor Admixture - A liquid admixture that inhibits corrosion of concrete-embedded steel in the presence of chloride ions. DCI® corrosion inhibitor is calcium nitrite based and manufactured by W. R. Grace & Co.-Conn.
C.Microsilica (silica fume) Concrete - Generally concrete made for high strength or extended durability. Microsilica is a highly active pozzolan.
D.Cementitious Material - Cementitious materials include cement, microsilica, ground blast furnace slag and fly ash.
1.05Submittals
A concrete admixture "Product Data Sheet" shall include brand name, manufacturer and dosage rate range.
1.06Delivery, Storage, And Handling For Job-Site Admixture Additions
NTSThe desired location for dispensing admixtures is the concrete batch plant where all ingredients can be recorded simultaneously on delivery ticket. However, certain situations may arise where job-site addition of admixtures may be beneficial to concrete performance. Job conditions should be given thorough review and pre-testing of materials should indicate preferred location for addition.
Admixture storage tanks and dispensing equipment shall be provided, installed and serviced by admixture manufacturer at no additional cost to the concrete producer.
PART II PRODUCTS
2.01Manufacturers
Admixture Manufacturer - Shall provide quality admixtures. All technical assistance and necessary dispensing equipment shall be provided at no additional cost. Manufacturer's certification of delivered admixtures shall be available upon request. A manufacturer's representative shall be available for consultation by telephone or on-site upon 72-hour notice by contractor. Representative shall be employed full time by manufacturer and posses technical admixture training and concrete mix design experience. All dispensing equipment shall assure accuracy and manufacturer representative shall instruct concrete batch man on its proper usage. Approval of admixture manufacturers shall be given by Architect/Engineer. Reputable manufacturers shall include:
1. W. R. Grace & Co.-Conn., Cambridge, MA
2.02Materials
Concrete Admixtures - Shall provide highest concrete performance and allow for most efficient placement for project requirements. Admixtures shall improve concrete properties including desired setting characteristics, and shall be used in accordance with manufacturer's recommendations. All admixtures shall be added at separate intervals or locations of mix cycle. Admixtures may also meet applicants CSB stands. All concrete admixtures provided for the work of this project shall be supplied by one manufacturer.
The following admixtures (and approved equals) shall be allowed:
NTSGeographical differences of material resources used in manufacture of concrete have been balanced with a variety of admixture formulations that optimize concrete performance. This is particularly true with air-entraining agents, water reducers, and retarders as products vary in local availability. For the most standard admixtures to quote for specification purposes check with manufacturer representatives. A full listing of Grace admixtures is available following this sample specification.
A.Air-Entraining Admixture: Air-Entraining admixture complying with ASTM C 260. Subject to compliance with requirements, provide Daravair® series or Darex® series admixtures by W. R. Grace & Co.-Conn.
B.Water Reducing Admixture: Water reducing admixture complying with ASTM C 494, Type A. Subject to compliance with requirements, provide one of the following admixtures by W. R. Grace & Co.-Conn:
1. WRDA® series admixture.
2. Daracem® 50, mid range water reducing admixture.
3. Daracem 55, mid range water reducing admixture.
- Daracem 65, mid range water reducing admixture.
- MIRA® series, mid range water reducing admixture.
C.Water Reducing and Retarding Admixture: Water reducing and retarding admixture complying with ASTM C 494, Type D. Subject to compliance with requirements, provide one of the following admixtures by W. R. Grace & Co.-Conn.:
1.Daratard® series admixture.
2.Recover® series admixture, hydration stabilizer for long-haul applications or extended placement beyond 4 hours.
D.Water Reducing, High Range Admixture: Water reducing, high range admixture (superplasticizer) complying with ASTM C 494, Type F or G, ASTM C 1017, Type 1 or 2. Subject to compliance with requirements, provide one of the following admixtures by W. R. Grace & Co.-Conn.:
1. Daracem 194. Daracem ML500
2. Daracem 1005. ADVA® Series
3. Daracem ML330
E.Accelerating Admixture: Accelerating admixture complying with ASTM C 494, Type C. Subject to compliance with requirements, provide one of the following admixtures by W. R. Grace & Co.-Conn.:
1. PolarSet®, non-chloride cold-temperature admixture.
2. DCI®, non-chloride admixture.
3. Daraccel®, chloride-type admixture.
NTSCalcium nitrite is a proven non-chloride accelerator as well as corrosion inhibitor. Quantities of calcium nitrite contained in PolarSet manufactured by W. R. Grace & Co.-Conn., Cambridge, MA provide assurance that it does not promote corrosion.
F.Corrosion Inhibitor: Calcium nitrite based corrosion inhibitor. Subject to compliance with requirements, provide one of the following admixtures by W. R. Grace & Co.-Conn.:
1. DCI
2. DCI-S
G.Microsilica Admixture: Microsilica admixture complying with ASTM C 1240-93. Subject to compliance with requirements, provide Force 10,000® by W. R. Grace & Co.-Conn. As a liquid slurry or a dry densified.
H.Dampproofing Admixture: Provide stearic acid based dampproofing admixture. Subject to compliance with requirements, provide Darapel® series admixtures by W. R. Grace & Co.-Conn.
I.Synthetic Fiber Admixture: Alkali-resistant, non-absorptive, non-corrosive synthetic fiber admixture complying with ASTM C 1116, Type 111, and manufactured from 100 percent virgin polypropylene in a micro filament form. Subject to compliance with requirements, provide the following synthetic fiber admixture by W. R. Grace & Co.-Conn.:
1. Grace MicroFiber™, for enhanced-finishing performance and crack reduction.
J.Controlled Low Strength Material Additive: Subject to compliance with requirements, provide DaraFill® by W. R. Grace & Co.-Conn. Coordinate with excavating, backfilling and compaction requirements.
2.03Concrete Mixes
A.Mix Design - all mix designs shall be proportioned in accordance with ACI 318 Chapter 4 and 5. If trial batches are used before construction start up, they shall be prepared by the concrete producer and may be witnessed by an independent testing laboratory approved by Engineer. (Expenses for mix design preparations shall be paid by_____). All mix designs to be used in Project shall be approved by the Engineer prior to use in Project. (Contractor/Subcontractor) shall be responsible for incorporating concrete of minimum strengths specified into structures (as noted on drawings). During the project, concrete mix design may be altered for workability requirements and weather conditions.
B.Proportions - all concrete shall be proportioned within limitations of Table A.
Table A. Format for specifying mix design and performance:
Class A-
Class B-
Class / Minimum Cementitious Lbs. Percy* / Minimum Compressive Strengths P.S.I. (MPA)
7-Day 28Day / Max. Size of Aggregate Inches (mm) / Air Entrained W/C ratio** / Special Admixtures Requirements / Slump Inches
(mm) / Entrained Air Content
(1) / (2) / (3) (4) / (5) / (6) / (7) / (8) / (9)
A. / ( ) / ( ) / ( ) / ( ) / ( ) / ( ) / ( )
B. / ( ) / ( ) / ( ) / ( ) / ( ) / ( ) / ( )
C. / ( ) / ( ) / ( ) / ( ) / ( ) / ( ) / ( )
Class C-
* Cementitious is minimum. Increase as necessary to meet conditions.
** Water-to-cementitious ratio is given for aggregates in saturated-surface-dry condition. Thus, total moisture of all aggregates, calculated by ASTM C 566 (84), less absorption of aggregate (ASTM C 127 and C 128) shall represent total free moisture in aggregate. To determine water/cementitious ratio, total free moisture of aggregates shall be added to batch water to estimate water content of concrete.
C.Chloride Limits - All concrete shall not exceed ACI 318 maximum chloride limits.
D.High Range Water Reducers - Specified water-to-cementitious ratio shall be adhered to. All concrete containing high range water reducers shall have a maximum (10) inches (250mm) slump unless otherwise approved.
1.High range water reducers shall meet all requirements of ASTM C 494 Type F (and G) (CSA 266.6) and shall be used in accordance with manufacturer's recommendations as required by project conditions.
2.The following concrete shall contain specified high range water-reducer:
a.All concrete with a water-to-cementitious ratio of 0.45 or less.
b.Specialty concrete such as made with microsilica, corrosion inhibitors, or concrete in potentially corrosive environments as defined by ACI 318-89.
c.At the contractor's request any other concrete if approved in submitted mix designs.
E.Corrosion Inhibitor Concrete
NTSAdd Section 03315 "Corrosion-Inhibiting Concrete Admixture" here. Since the chloride loading rate and final concrete quality are unknown factors, Grace can not guarantee the longevity of the protection offered by DCI. Quality concrete as recommended by ACI will slow the ingress of chlorides into the concrete while DCI will significantly reduce the corrosion rate once the chlorides reach the rebar. Neither quality concrete nor DCI will stop corrosion forever, but both will retard the onset of corrosion and increase a structure's service life.
F.Microsilica Concrete
NTSSpecifier should add Section 03320 "Microsilica Concrete" here.
G.Fiber Reinforcement for Concrete
NTSSpecifier should add Section 03240 "Fiber Reinforcement for Concrete" here.
H.Dampproofing Concrete
NTSDampproofing Admixtures (water repellents) improve the overall durability of concrete subjected to damp conditions. Moisture transmission is lowered, efflorescence is greatly reduced or prevented and an algal growth is discouraged. An ASTM specification has not been developed for products of this type, however, simple absorption tests involving complete or partial immersion in water are used. Dampproofers may have a small affect on other concrete properties. Because it is a dispersion, a slight increase in the level of entrained air will occur. Adjustments to the mix to maintain the desired level of air is recommended. Trial mixes incorporating the specific materials (cement, sand, admixes) to be employed must be made to ascertain proper performance.
1.Dampproofing (water repellent) admixtures for ready-mixed concrete shall be added to all exterior exposed concrete. These admixtures shall be hydrophobic and shall increase the contact angle of water, so reducing wetting of the surfaces. The admixture shall be a liquid or a dispersion and shall be added to the mix at the time of batching.
2.Provide Darapel® by W. R. Grace & Co.-Conn.
I.Controlled Low Strength Material
NTSSpecifier should add Section 02225 "Controlled Low Strength Material" here.
J.Crack-Resistant Concrete Finishing System
NTSSpecifier should add Section 03350 "Crack-Resistant Concrete Finishing System" here.
PART III EXECUTION
3.01Admixture Manufacturer's Field Service
A.General
1.Admixture manufacturer shall provide a source for incidental consultation through completion of the concrete portion of the project as herein before specified.
2.Where concrete contains high range water-reducer, non-chloride accelerator, corrosion inhibitor or microsilica, a qualified manufacturer's representative shall observe project start-up of concrete placements and offer recommendations.
B.Preconstruction Conference and Trial Mixtures for Concrete Containing Corrosion Inhibitor, Microsilica, and High Range Water Reducers Containing Concrete.
1.A preconstruction meeting of Engineer, Contractor, Finisher and Concrete Producer shall take place at least two weeks prior to project start-up. A representative from W. R. Grace & Co.-Conn. shall be present to discuss corrosion inhibitor (DCI), microsilica (Force 10,000), or high range water-reduced concrete. Topics of discussion shall include: concrete handling, placing, finishing and curing.
2.A minimum of 4 cubic yard (3 cubic meters) trial mixture containing (corrosion inhibitor DCI , microsilica Force 10,000 or high range water-reducer Daracem-100/WRDA-19) shall be placed at the project site utilizing proposed concrete mix and methods of placing, finishing and curing. This shall occur at least one week before actual concreting (with particular admixture) begins. A representative from W. R. Grace & Co.-Conn. shall be present.
3.This specification for concrete shall be made available to the manufacturer of the concrete admixture (corrosion inhibitor, microsilica, high range water-reducer) at least three weeks prior to the invitation to bid by the design engineer.
C.Project Start-Up
1.A representative of W. R. Grace & Co.-Conn. shall be present during project start-up if required by the design engineer.
3.02Admixture Additions on Job Site
Job site additions shall be limited to high range water reducers, non-chloride accelerators, and corrosion inhibitors. Instructions to discharge admixtures shall be furnished as herein before specified. Material Safety Data Sheet and storage labeling shall be available at job site and conform to current governing regulations.
A.High Range Water Reducers:
1.Concrete shall arrive at a slump of 2 to 4 inches (50 to 100 mm). Water additions at job site shall be limited to comply with water-to-cementitious ratio requirements.
2.Following addition of high range water-reduced concrete, a minimum of 70 revolutions or 5 minutes of mixing shall be completed to assure a consistent mixture.
B.All concrete with other admixture additions shall mix a minimum of 70 revolutions or 5 minutes to assure a consistent mixture.
3.03Environmental Conditions
A.Hot weather concreting shall follow recommendations of ACI 305. When concrete temperatures exceed 80o F, ASTM C 494 Type D and G, water reducing, and high range water reducing retarding admixtures shall be used in accordance with manufacturer's recommendations.
B.Cold weather concreting shall follow recommendations of ACI 306, particularly Table 1.4.1-"Recommended Concrete Temperatures" and Table 1.4.2-"Protection Recommended for Concrete Placed in Cold Weather". When ambient placement temperatures are less than 50o F, all concrete shall contain PolarSet accelerating admixture. At temperatures above 50o F, the contractor has option to use this admixture for all other concrete to accelerate early strength gains.
NTSNon-chloride accelerating admixtures should not be considered a concrete "anti-freeze" agent. Fresh concrete is considered protected from deleterious freezing effects after initial set is achieved and concrete is protected from ingress of additional water. Use of non-chloride accelerators should not substitute recommendations for protection from concrete freezing as detailed in ACI 306. Standard industry precautions should be employed to properly cure concrete.
3.04Finishing And Curing
A.High air content concrete, corrosion inhibitor concrete, microsilica concrete, and high range water-reduced concrete do not bleed similarly to normal concrete. In order to avoid plastic or drying shrinkage cracks during warm, dry or windy weather ACI 302 "Guide for Concrete Floor and Slab Construction" and ACI 308 "Standard Practice for Curing Concrete" shall be followed during the handling, finishing or curing of the concrete. To overcome possible concrete shrinkage problems, the use of wind breaks, sun shades, and fog misting is recommended. In general, the surface shall be maintained at a high humidity during placing and finishing operations. Free-standing water is not allowed.
NTSResearch has found that the use of polypropylene fibers reduces plastic shrinkage cracking potential. See "Fiber Reinforcement for Concrete" Section 03240, for further information.
B.Fog misting is required when the rate of evaporation exceeds 0.2 lb./ ft3/hr (ACI 308 section 1.2.1) (0.1 lb./ ft3/hr for Force 10,000 and DCI concrete). Fogging shall continue after the finishing operation until prewetted burlap or other approved curing material is placed over the concrete. Fog misting is not to be used to apply water to the surface of the concrete to facilitate lubrication for finishing purposes.
C.An acceptable fog misting system includes the following items, available from commercial rental agencies: Nozzle: Brand "Mi-T-M Corp." (Peosta, Iowa). Wide angle (45o, to 50o angle) for low wind operation; sharp angle (10o, to 15o) for windy operations. Water Pressure System: Brand "Mi-T-M Corp." (Peosta, Iowa). 2,500 psi, 2 to 3 gallons per minute.
D.Water cure is the best method for curing concrete with reduced bleeding. When the weather conditions are dry and windy, fogging above the surface of the concrete shall continue after the finishing operation until prewetted burlap can be placed over the flatwork surface. The burlap shall cover all flatwork and be kept wet for a minimum of seven days or until the time necessary to attain 70% of specified compressive strength (ACI 308 section 3.1.3).
Type A / Type B / Type C / Type D (& B) / Type E / Type F / Type GWRDA® / DARASET®
DCI®
DARACCEL®
POLARSET® / DARACCEL / DARACEM ® 19
DARACEM® 100
DARACEM ML 330
ADVA® Flow
ADVA® Cast / DARACEM® 100
END OF SECTION
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