Durability Studies

No single mechanism is responsible for all types of freeze-thaw damage. The physics of freeze-thaw behavior depend on material types, pore structures, and exposures. It is not surprising that there is no single durability test that applies to all situations. Highbridge is equipped to provide solutions for your project requirements and can help you determine the right testing protocol.

Salt distress is a leading cause of deterioration in buildings. To evaluate the potential for salt migration and expansion within masonry units, Highbridge offers permeability and salt crystallization testing. For cementitious materials, petrographic and chemical studies can be used to evaluate microstructure and porosity and to identify binders or admixtures that may increase salt resistance in certain aggressive environments.

Aggregates represent over 75% of a concrete mix and it is critical that they are chosen to meet the requirements of the application. Our petrographers identify the microtextural and mineralogical features that govern aggregate suitability. Our chemists determine whether concrete that has suffered aggregate reactivity contains sufficient alkali for reactions to continue. Our technical staff use mortar bar expansion tests for ASR prediction and to quantify pessimum proportions.

When evaluating replacement stone, potential changes in appearance are often as important as mechanical performance. Highbridge has adapted a century-old method to accelerate the development of natural patina. In several weeks, we can simulate the color and texture that is expected to develop on newly-installed stone as it ages. We can give results qualitatively or provide quantitative colorimetric data in the CIELAB color space.

Cracking in sandstone and limestone is not always the result of freeze-thaw cycling. Wetting and drying alone can cause significant damage. Our lab uses x-ray diffraction to detect swelling clays that are often responsible for progressive scaling. We also quantify hydric expansion through short-term microstrain measurements. For production stone, our measurements of static elastic modulus and tensile strength can be used to estimate the percentage of total yield stress generated by wetting cycles.

Acid resistance testing can serve as a general proxy for stone performance and decay, particularly when the material under consideration is expected to be used in an aggressive service environment. Highbridge offers testing in accordance with ASTM standards for slate and the BRE standards for sandstone. These tests evaluate surface softening of stone after immersion in sulfuric acid.