GIS Mapping
Matergenics understands how important building preservation is for many individuals. Our mapping service provides our clients with a comprehensive knowledge of atmospheric salt deposition and related soil properties to make informed decisions to best manage their assets. Using our patented methodology, we identify areas where concrete rebar is susceptible to corrosion especially in buildings, concrete slabs, and wall near the ocean.
ATMOSPHERIC MAPPING
The Deposition of atmospheric aerosols is an important factor in above-grade concrete corrosion. High concentrations of aerosols can lead to the premature degradation of structures.
Atmospheric aerosol deposition and wetness play a crucial role in the overall corrosivity of the environment. Our assessment of atmospheric corrosivity is based on international standard ISO 9223. However, in addition to the data used in the standard, we also consider other physical properties of the structure location. While not all of the following layers are used to produce the final corrosion map, an in-depth analysis can be conducted with the extra information.
Data used in Atmospheric maps
- Sulfur Dioxide Deposition
- Time of Wetness
- Oxidized Nitrogen
- Precipitation
- Chloride Deposition
- Elevation
- Wind Speed & Direction
International Standard ISO 9223
ISO 9223 Establishes A Classification System For The Corrosivity Of Atmospheric Environments. Atmospheric Corrosivity Falls In One Of Five Categories Set By The Standard. C1 Represents Rural Environments And C5 Represents Marine Atmospheres. The Corrosivity Category Of The Area Of Interest Provides A Basis For Materials Selection And Protective Measures With Regards To Specific Application, Particularly Relating To Service Life.
The Corrosion Categories Are Based On The Following Three Parameters:
DEPOSITION OF SULPHUR DIOXIDE
Sulfur dioxide plays an important role in atmospheric corrosion in urban and industrial areas. It is absorbed on metal surfaces, has a high solubility in water and tends to from sulfuric acid in the presence of moisture. Sulfate ions are formed in the surface moisture layer by the oxidation of SO2, and their formation is considered to be a corrosion accelerator.
AIRBORNE CHLORIDES
Chlorides are a major component of most salts, which accelerate corrosion due to their hydrophilic nature. When sat attracts water and dissociates, it produces a highly conductive electrolyte. Moreover, chlorides are a main catalyst for pitting corrosion, which is an auto catalytic, localized attack. Chlorides are known to cause hydrolysis and create acidic chlorides.
TIME OF WETNESS
Time of wetness is a measure of how much time the material will be in contact with a conducting solution. Wet surfaces are caused by factors such as dew, rainfall, melting snow, or high humidity. These conditions are estimated by looking at the time during which the relative humidity is greater than 80% and the temperature is above 0 degrees Celsius.
Atmospheric and Soil Mapping
GIS mapping allows our clients to understand and visualize the factors leading to concrete corrosion for both above & below ground
Data used in Soil maps
- Soil Resistivity
- Soil Types, Including Clay Content
- Drainage Characteristics
- Soil Salinity
- Soil pH
- Depth to Water Table
SOIL MAPPING
Soil composition and distance from shore is an important factor in Below-grade concrete corrosion. Water table contamination can contribute to the corrosion of rebar.
Soil properties play a crucial role in the overall corrosivity of soil. Physio-chemical properties describe the corrosivity of liquid phase in soil while the geological properties estimate moisture content and the ability of the soil to retain that moisture. Matergenics considers both to estimate corrosion risk. A few of the properties that are included in our corrosion maps are listed below.
Mapping Concrete assets near oceans
The location of concrete structures is Extremely important when mapping the environment. Distance to shoreline could indicate high potential of water table contamination with salt, leading to below ground rebar corrosion.
FINAL CORROSION RISK ASSESSMENT MAPS
A proprietary method is utilized by Matergenics to create a final corrosion risk assessment map for the area of interest, outlining areas of low, medium, and high corrosion risk potential. The accuracy of this algorithm has been field tested and proven in multiple projects.
Soil Corrosion Risk Assessment
Each soil data layer used in the analysis is assigned a weighting factor that corresponds to the level of importance in determining soil corrosivity. A final risk assessment map is produced
Atmospheric Corrosion Risk Assessment
Each data layer included in the map is weighed and assign a corrosivity index to each location on the bap based on the atmospheric data, wind data, and corrosive gasses by chemical plants.
