Concrete & Aggregates
Our petrographers are experts in cementitious materials, construction technology, and the science behind concrete deterioration. Our laboratory is fully equipped for microscopy, chemical analysis, mechanical testing, and durability evaluations.
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Condition Surveys
Rehabilitation of older buildings requires visual assessment by experienced professionals. However, these surveys cannot always determine causes of cracking or deterioration. Petrography is an extension of the visual survey at a finer resolution and this can be supplemented by chemical and physical tests to quantify salt loads or critical material properties.
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Aggregate Evaluations
Aggregate is not an inert ingredient in concrete. Unstable components in natural stone sources can result in aggressive deterioration. Highbridge uses petrography and x-ray diffractometry to identify deleterious constituents either in preproduction or as part of a forensic study of failed concrete. We also perform stability experiments for candidate aggregate sources.
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Historical Concrete
Concrete is not just a modernist material. On its way to the mix designs we know today, concrete has been present as oyster shell tabby in coastal regions, tamped natural cement mixes for early infrastructural works, and lightweight cinder concrete in early high-rise construction. Highbridge is uniquely qualified to assist preservation professionals in evaluating historic concrete structures.
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Infrastructure
Concrete is a highly versatile material and we expect it to perform under a variety of demanding service conditions. Effective infrastructure management requires an understanding of how well concrete resists these stresses. Engineers use our data to design effective repairs, mitigate future deterioration, and reduce overall life cycle costs.
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Parking Structures
Automobile exhaust and deicing salts are both agents that can accelerate steel reinforcement corrosion in parking structures. The structure may be subject to water saturation and freeze-thaw cycles particularly along ramps and exterior walls. Original precasting methods may have resulted in expansive cracking due to delayed ettringite formation. Highbridge understands these unique conditions and tailors its examinations to provide economical analytical solutions.
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New Construction
Low concrete strengths, surface defects, and cracking are common concerns that can relate to incorrect specifications, mix design deviations, or workmanship defects in new construction projects. If not resolved by an engineer’s review and nondestructive field testing, our lab scientists step in with core tests and petrography to help diagnose the cause.
Test Methods for Concrete & Aggregate
Highbridge performs many tests in accordance with standard test methods but also constructs protocols for property characterization and durability evaluations using proprietary methods.
Concrete Test Methods:
ASTM C39 Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
ASTM C42 Standard Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete
ASTM C215 Standard Test Method for Fundamental Transverse, Longitudinal, and Torsional Frequencies of Concrete Specimens
ASTM C457 Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
ASTM C469 Standard Test Method for Static Modulus of Elasticity and Poisson's Ratio of Concrete in Compression
ASTM C642 Standard Test Method for Density, Absorption, and Voids in Hardened Concrete
ASTM C666 Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing
ASTM C856 Standard Practice for Petrographic Examination of Hardened Concrete
ASTM C1084 Standard Test Method for Portland-Cement Content of Hardened Hydraulic-Cement Concrete
ASTM C1152 Standard Test Method for Acid-Soluble Chloride in Mortar and Concrete
ASTM C1218 Standard Test Method for Water-Soluble Chloride in Mortar and Concrete
AASHTO T 260 Standard Method of Test for Sampling and Testing for Chloride Ion in Concrete and Concrete Raw Materials
Aggregate Test Methods:
ASTM C40 Standard Test Method for Organic Impurities in Fine Aggregates for Concrete
ASTM C227 Standard Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method)
ASTM C295 Standard Guide for Petrographic Examination of Aggregates for Concrete
ASTM C586 Standard Test Method for Potential Alkali Reactivity of Carbonate Rocks as Concrete Aggregates (Rock-Cylinder Method)
ASTM C1260 Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method)
ASTM C1293 Standard Test Method for Determination of Length Change of Concrete Due to Alkali-Silica Reaction
ASTM C1567 Standard Test Method for Determining the Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials and Aggregate (Accelerated Mortar-Bar Method)
Proprietary Instrumental Analysis:
Highbridge partners with trusted institutions and commercial providers to offer research-grade instrumental analysis.
X-Ray diffraction analysis of water-soluble salts extracted from concrete
Scanning electron microscopy and energy-dispersive x-ray spectroscopy
Thermogravimetric analysis for identification or quantification of volatile constituents
Fourier transform infrared spectroscopy of organic constituents
Pyrolysis - Gas chromatography / mass spectroscopy for organic components
Transient plane source for thermal conductivity and heat capacity
Concrete (Cast in place) Specifications:
ASTM C94 Standard Specification for Ready-Mixed Concrete
ASTM C685 Standard Specification for Concrete Made By Volumetric Batching and Continuous Mixing
Aggregate Specifications:
ASTM C33 Standard Specification for Concrete Aggregates
ASTM C330 Standard Specification for Lightweight Aggregates for Structural Concrete
ASTM C331 Standard Specification for Lightweight Aggregates for Concrete Masonry Units
ASTM C1436 Standard Specification for Materials for Shotcrete