CADD - Concrete Admixtures Testing
Testing services for your products and materials
What are Concrete Admixtures?
Concrete admixtures are substances that are added to concrete during mixing to improve its properties. There are many different types of concrete admixtures, each with its own unique purpose. Some of the most common types of concrete admixtures include:
- Water reducers: Water reducers are admixtures that reduce the amount of water needed to make concrete. This can improve the strength and durability of concrete.
- Air-entraining admixtures: Air-entraining admixtures add tiny air bubbles to concrete. This makes concrete more workable and durable, and it also helps to improve its resistance to freezing and thawing.
- Set retarders: Set retarders slow down the setting time of concrete. This can be helpful in hot weather or when concrete needs to be placed in large pours.
- Set accelerators: Set accelerators speed up the setting time of concrete. This can be helpful in cold weather or when concrete needs to be placed quickly.
- Corrosion inhibitors: Corrosion inhibitors help to protect concrete from the harmful effects of water and chemicals.
- Coloring admixtures: Coloring admixtures add color to concrete. This can be used to create decorative concrete or to match the color of other materials on a project.
Concrete admixtures are a valuable tool for improving the properties of concrete. By selecting the right admixtures for the job, you can create concrete that is stronger, more durable, and more resistant to the elements.
Here are some of the benefits of using concrete admixtures:
- Improved strength: Concrete admixtures can improve the strength of concrete by up to 25%.
- Improved durability: Concrete admixtures can improve the durability of concrete by making it more resistant to water, chemicals, and freezing and thawing.
- Improved workability: Concrete admixtures can improve the workability of concrete by making it easier to place and finish.
- Reduced cost: Concrete admixtures can reduce the cost of concrete by reducing the amount of cement needed.
What is Concrete Admixtures Testing?
Concrete admixtures testing is the process of evaluating the properties of concrete admixtures to ensure that they meet the required specifications. This is done to ensure that the admixtures will perform as intended when they are used in concrete.
There are many different types of concrete admixtures testing, each designed to measure a different property of the admixture. Some of the most common concrete admixtures tests include:
- Water reduction efficiency: This test measures the ability of the admixture to reduce the amount of water needed to make concrete.
- Air entrainment efficiency: This test measures the ability of the admixture to entrain air bubbles in concrete.
- Set retardation: This test measures the ability of the admixture to slow down the setting time of concrete.
- Set acceleration: This test measures the ability of the admixture to speed up the setting time of concrete.
- Corrosion inhibition efficiency: This test measures the ability of the admixture to protect concrete from the harmful effects of water and chemicals.
- Colorfastness: This test measures the ability of the admixture to retain its color over time.
Concrete admixtures testing is an important part of the quality assurance process for concrete admixtures. By testing admixtures, manufacturers can ensure that their admixtures meet the required specifications and will perform as intended when they are used in concrete.
Here are some of the benefits of concrete admixtures testing:
- Ensures that admixtures meet the required specifications: Concrete admixtures testing can help to ensure that admixtures meet the required specifications, such as water reduction efficiency, air entrainment efficiency, set retardation, set acceleration, corrosion inhibition efficiency, and colorfastness.
- Identifies potential problems: Concrete admixtures testing can help to identify potential problems with admixtures, such as manufacturing defects or material flaws.
- Improves quality: Concrete admixtures testing can help to improve the quality of admixtures by identifying and correcting problems early in the manufacturing process.
- Reduces costs: Concrete admixtures testing can help to reduce costs by preventing the use of defective admixtures and by improving the quality of admixtures.
In addition to the above, concrete admixtures testing can also be used to:
- Monitor the condition of admixtures in service
- Identify areas where admixtures are likely to fail
- Optimize admixture maintenance schedules
- Develop new admixture materials and designs
Concrete admixtures testing is a valuable tool for ensuring the quality and safety of concrete admixtures. By testing admixtures, manufacturers can help to prevent defects and failures, and improve the overall performance of admixtures.
Concrete Admixtures Testing Plans
The following is a list of tests that are often included in testing plans for concrete admixtures:
|Property||Material||ASTM / Method||Details|
|Standard Admixture Specification||Admixture for Concrete||ASTM C494 / AASHTO M194|
Standard Specification for Chemical Admixtures for Concrete
Standard procedure for evaluating an admixture’s effect on a concrete mix. Six batches are cast in the laboratory. Three with admixture, and three control batches. Properties are compared and evaluated for conformance with the limits set for that specific type of admixture.
|Air Entraining Admixture Specification||Air-Entraining Admixtures||ASTM C260 / AASHTO M154|
Standard Specification for Air-Entraining Admixtures for Concrete
Standard procedure for evaluating an air-entraining admixture’s effect on a concrete mix. Six batches are cast in the laboratory. Three with admixture, and three control batches. Properties are evaluated for conformance with the limits set for in the specification.
|Air Entraining Admixture Test Methods||Air-Entraining Admixtures||ASTM C233|
Test Method for Air-Entraining Admixtures for Concrete
Describes the materials to be used, and the modifications to the methods listed below, as set forth in ASTM C260/AASHTO M154. Test methods are used to evaluate relative performance between control batches and test batches.
|Compressive Strength||Concrete Cylinders||ASTM C39|
Compressive Strength of Cylinderical Concrete Specimens
Molded or cored concrete specimens are tested in compression and the strength is reported on a pounds/square inch basis.
|Flexural Strength (Modulus of Rupture)||Concrete Beams||ASTM C78|
Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)
Concrete beams are cast or sawn from hardened specimens. Specimens are placed on the third-point loading appatus with an appropriate span, and are subsequently loaded to failure. The load, fracture location, and specimen dimensions are evaluated to determine the flexural strength (modulus of rupture) is reported on a pounds/square inch basis.
|Density (Unit Weight), Yield, Air Content||Fresh Concrete||ASTM C138|
Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete
Performed on freshly cast material only. Wet concrete is consolidated in a calibrated unit weight container and weighed to determine the actual unit weight per volume of the material vs the theoretical properties.
|Consistency (Slump)||Fresh Concrete||ASTM C143|
Slump of Hydraulic Cement Concrete
Performed on freshly cast material only. Wet concrete is consolidated in a calibrated “slump cone”. The cone is removed, and the consistency (slump) of the material is determined by measuring the change in height of the cone of concrete.
|Length Change||Concrete Beams||ASTM C157|
Length Change of Hardened Hydraulic-Cement Mortar and Concrete
Mortar or concrete is cast into beams and cured per ASTM C157 procedures. The lengths of the beams are measured, and the beams are allowed to cure in standard conditions (either lime water or laboratory air) for a period of up to 64 weeks. Intermetent readings are taken to determine the length change of the material.
|Bleeding||Fresh Concrete||ASTM C232|
Bleeding of Concrete
Fresh concrete is consolidated in an appropriate container. The sample is kept in standard laboratory conditions, with the bleed water periodically removed per ASTM C232 methods. The total bleed water is expressed as a percent of the net mixing water in the test specimen.
|Time of Setting||Fresh Concrete||ASTM C403|
Time of Setting of Concrete Mixtures by Penetration Resistance
Performed on freshly cast material only. The coarse material in fresh concrete is removed, with the remaining material collected in an appropriate container. Material is allowed to cure, and is periodically penetrated with a calibrated concrete penetrometer. A curve of penetration resistance over time is used to calculate initial and final setting times of the material.
|Freeze Thaw Resistance (Durability Factor)||Concrete||ASTM C666|
Resistance of Concrete Beams to Rapid Freezing and Thawing.
Concrete prisms are exposed to 300 cycles of rapid freezing and thawing. The fundamental transverse frequency is determined at 30 cycle intervals, and this is used to determine the durability factor rating (out of 100).
|Infrared Spectrography Analysis (Fourier Transform Infrared Spectroscopy – FTIR)||Admixture||ASTM C494 Section 18.1 / ASTM E1252|
Infrared Analysis of Admixture for Concrete
Analysis is performed to generate the infrared absorption spectrum, which is then used for qualitative analysis when compared to previous tests run on the same admixture.
|Residue Content||Admixture||ASTM C494 Section 18.2 / 18.3|
Residue Content by Oven Drying
Admixture is dispersed in an appropriate container and oven dried per the methods described for liquid or non-liquid admixtures. The mass of residue remaining after a standard drying time is the residue content.
|Relative Density (Specific Gravity)||Liquid Admixture||ASTM C494 Section 18.4|
Relative Density (Specific Gravity)
For liquid admixtures, samples are brought to the test temperature and a set of NIST traceable calibrated hydrometers are used to evaluate the specific gravity of the material.
|pH||Liquid Admixture||ASTM E70|
pH of Aqueous Solutions with the Glass Electrode
Calibrated electrodes are used to measure pH.
|Chloride Content||Admixtures||BS-EN 480-10|
Water-Soluble Chloride Content
Sample is dispersed with chemicals per standard procedures, depending on the specific type of admixture being tested. A titration is then performed using sodium chloride and silver nitrate solutions to determine the chloride content of the admixture.
Concrete Admixtures Testing Standards
Standards and acceptance criteria related to concrete admixtures testing:
- AASHTO M154 – Air-Entraining Admixtures for Concrete
- AASHTO M194 – Chemical Admixtures for Concrete
- ASTM C39 – Compressive Strength of Cylindrical Concrete Specimens
- ASTM C78 – Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)
- ASTM C138 – Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete
- ASTM C143 – Slump of Hydraulic-Cement Concrete
- ASTM C157 – Length Change of Hardened Hydraulic-Cement Mortar and Concrete
- ASTM C232 – Bleeding of Concrete
- ASTM C233 – Air-Entraining Admixtures for Concrete
- ASTM C260 – Air-Entraining Admixtures for Concrete
- ASTM C403 – Time of Setting of Concrete Mixtures by Penetration Resistance
- ASTM C494 – Chemical Admixtures for Concrete
- ASTM C666 – Resistance of Concrete to Rapid Freezing and Thawing
- ASTM C1017 – Chemical Admixtures for Use in Producing Flowing Concrete
- ASTM C1141 – Admixtures for Shotcrete
- ASTM C1384 – Admixtures for Masonry Mortars
- ASTM C1582 – Admixtures to Inhibit Chloride-Induced Corrosion of Reinforcing Steel in Concrete
- ASTM C1622 – Cold-Weather Admixture Systems
- ASTM E70 – pH of Aqueous Solutions With the Glass Electrode
- ASTM E1252 – General Techniques for Obtaining Infrared Spectra for Qualitative Analysis
- BS EN 480 – Admixtures for Concrete, Mortar and Grout
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