Clay soil
A very tiny soil particle that can only be seen through a scanning tunneling microscope. There are many different mineral compositions of clay. Many types of clay have an affinity for water, known as “clay suction.” Clay has a negative charge and is attracted to water with a positive charge. Many types of clay expand (swell) when exposed to water.

Collapsible/compressible soil
Usually sands and silt (larger than clay soil particles) that consolidate when exposed to water or sometimes just the weight (overburden) of something on top of it.

Cold joint
An area between two portions of concrete placed at different times. It lacks continuous structural integrity.

Concrete
A common form of pavement made up of sand, rocks, cement, and water. First invented by the Romans. When combined, a chemical reaction occurs, transforming it into a solid material.

Cement
A component of concrete. Made from calcium (dead lobsters) that is transformed by extreme heat and ground to a fine powder. The Romans first used natural Pozzolan, derived from the volcano of Mt. Vesuvius.

Cut
In soil nomenclature, this refers to excavating soil to create a level surface for construction.

Deflection
Deviation from a straight line. Usually meant to show evidence of a failure from differential movement. 

Evapotranspiration
The cycle of water vapor returning to the atmosphere from soil and bodies of water.

Fill
In soil nomenclature, the process of adding soil to level out a site for construction.

Floor level survey
Also known as a manometer survey. Floor elevations (height) of the floor/foundation are measured and recorded for analysis to identify settlement or heave.

Floor slab
The concrete that is placed as flooring in a house. In conventional foundations, it is not part of the foundation system.

Footing
The part of a foundation that rests on the soil to support loads above it.

Geotechnical
The science of soil mechanics. This field is usually considered a branch of civil engineering, distinct from structural engineering, which focuses on structures above the ground.

Heuristic
A simple shortcut for reasoning to explain complex systems that can’t be simplified into analogies.

Micro pile
A steel pile driven into the soil with percussion, usually grouted simultaneously. It can drill through rocks that helical and push piles cannot penetrate.

Nomenclature
The terms commonly used by a specific industry, like those in this glossary.

Polyurethane
A type of chemical that reacts with water or other catalysts. It has many forms and uses. Some are hydrophilic (water-attracting), while others are hydrophobic (water-repelling). Some swell when reacting, others simply gel and harden. They usually react faster than epoxy chemical reactions. This has become the material of choice for leveling sidewalks.

Post-tension slab
Concrete with steel cables tensioned after being poured. This increases the stiffness of the concrete. Also referred to as post-tensioned foundations.

Refusal
In pile installation, where the pile encounters soil hard enough to stop advancing. The load it will support can then be calculated.

Settlement
In the context of foundations, this occurs when a structure sinks into the ground.

Stem wall
A small wall that sits on footings to support the frame or masonry above.

Stratum
A distinct soil layer, one of many. Each layer can consist of different mineral compositions, density, and water content.

Topography
The mapping of a surface. Usually done with lines to show elevation (height) differences.