How Can Rapid Chloride Permeability Testing & Aggregate Prequalification Help You?
Concrete is a primary construction material that provides flexibility, ease of construction, and durability over most other materials. However, there are conditions and constituents that can reduce the longevity of concrete. Exposure to extreme weather conditions and chlorides -- or the use of reactive aggregates -- will severely shorten the useful life of a concrete structure.
With increased pressure on ready-mix concrete producers and contractors (especially those involved in federally-funded transportation projects) to secure longer service life for their concrete products and structures, now is a perfect time to determine an action plan to deliver the vital qualification/pre-qualification of aggregate and concrete mixtures that you need.
And this is where Froehling & Robertson, Inc. can help.
Rapid Chloride Permeability Testing
One of the key tools utilized by F&R to help our clients is our Rapid Chloride Permeability testing and evaluation service. Recently, F&R added new computer-controlled equipment that can constantly monitor up to eight specimens at a time and record all necessary data required in the test procedure. This new equipment has significantly increased our test volume and effectiveness of this ASTM C1202 governed procedure.
Chloride permeability is used in:
- Compliance Verification of Field Cast Specimens
- QC/QA Monitoring
- Pre-Qualification & Assessment of Proposed Concrete Mix Designs
- Referee Testing
- Deficiency Evaluation of Concrete Core Specimens
The RCP test was originally conceived of as part of a Federal Highway Administration research program to develop techniques to nondestructively evaluate the chloride permeability of in-place concrete. Designing concrete mixtures with enhanced resistant to the potential problems stemming from invasive chloride ions, improves the overall quality of the structure and extends the useful life.
F&R’s RCP testing service is in full compliance with ASTM C1202, “Standard Test Method for Electrical Indication of Concrete’s Ability to Resist Chloride Ion Penetration.”; AASHTO T277, “Standard Method of Test for Rapid Determination of the Chloride Permeability of Concrete” and Virginia Department of Transportation, VTM-112.
Aggregate & Concrete Qualification Evaluations
The combination of fine and coarse aggregates constitutes the largest portion of concrete mix. Preventing or lessening the aggregate-related problems in concrete is necessary in producing a quality product. Not all aggregates are the same, and changing sources can result in short and long term performance issues.
Preventing or lessening aggregate related problems in concrete is necessary in producing a quality product. Not all aggregates are the same and changing sources can result in the short and long term performance issues. The short term affects could be higher water demand, entrained air issues or lower concrete compressive strength. The major concern is potential long term harmful effects of non-qualified aggregates resulting in shorten concrete life due to alkali and alkali-silica reactivity of aggregates and potential alkali reactivity of carbonate rock in concrete.
Many specifications of critical projects today mandate that aggregate and aggregate combinations be pre-qualified through testing to determine if they have a destructive effect on the concrete. Additionally, there may also be the need to pre-qualify the aggregate and cement combination for reactivity potential.
F&R provides the specific, independent, third-party evaluation and testing services necessary to prequalify aggregate and cement-aggregate combinations as well as determine the relative effectiveness of Supplementary Cementation Materials for specific projects or when new aggregate or cement sources are under consideration. These ASTM procedures include:
- C227 – Standard Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method)
- C289 – Standard Test Method for Potential Alkali-Silica Reactivity of Aggregates (Chemical Method) (Sub-Contract required)
- C295 - Standard Guide for Petrographic Examination of Aggregates for Concrete
- C441 – Standard Test Method for Effectiveness of Pozzolans or Ground Blast-Furnace Slag in Preventing Excessive Expansion of Concrete Due to the Alkali-Silica Reaction
- C586 – Potential Alkali Reactivity of Carbonate Rocks as Concrete Aggregates (Rock-Cylinder Method)
- C1260 – Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar- Bar Method)
- C1293 – Standard Test Method for Determination for Length change of Concrete Due to Alkali-Silica Reaction
- C1202 – Standard Test Method for Electrical Indication of Concretes Ability to Resist Chloride Ion Penetration
Conclusion
F&R stands ready to provide you with the tools and professional capability you need to perform the necessary qualification/prequalification of aggregates and concrete mixtures.
So contact us and let us put our skills to work for you!