Soil cement is a

construction material This is a list of building materials. Many types of building materials are used in the construction industry to create buildings and structures. These categories of materials and products are used by architects and construction project managers ...

, a mix of pulverized natural

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

with small amount of

portland cement Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th ce ...

and

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

, usually processed in a tumbler, compacted to high density. Hard, semi-rigid durable material is formed by hydration of the cement particles. Soil cement is frequently used as a construction material for pipe bedding, slope protection, and road construction as a

subbase In topology, a subbase (or subbasis, prebase, prebasis) for a topological space X with topology T is a subcollection B of T that generates T, in the sense that T is the smallest topology containing B. A slightly different definition is used by so ...

layer reinforcing and protecting the

subgrade In transport engineering, subgrade is the native material underneath a constructed road,http://www.highwaysmaintenance.com/drainage.htm The Idiots' Guide to Highways Maintenance ''highwaysmaintenence.com'' pavement or railway track (US: railroad ...

. It has good

compressive In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elong ...

and

shear strength In engineering, shear strength is the strength of a material or component against the type of yield or structural failure when the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a materi ...

, but is

brittle A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Bre ...

and has low tensile strength, so it is prone to forming cracks. Soil cement mixtures differs from Portland cement concrete in the amount of paste (

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mi ...

-water mixture). While in Portland cement concretes, the paste coats all aggregate particles and binds them together, in soil cements the amount of cement is lower and therefore there are voids left, and the result is a cement matrix with nodules of uncemented material. CMS was invented by Benjamin Harrison Flynn to pave roads in Louisiana after WW1.

Types of soil cements

Cement-modified soils (CMS)

A cement-modified soil contains a relatively small proportion of Portland cement, less than in ordinary soil-cement."Cement-Modified Soil (CMS)" Portland Cement Association accessed March, 16 2015
/ref> The result is caked or slightly hardened material, similar to a soil, but with improved mechanical properties such as lower

plasticity Plasticity may refer to: Science * Plasticity (physics), in engineering and physics, the propensity of a solid material to undergo permanent deformation under load * Neuroplasticity, in neuroscience, how entire brain structures, and the brain it ...

, increased bearing ratio and shear strength, and decreased volume change. The purpose of modifying soil with Portland cement is to improve a substandard soil's engineering qualities.

Soil-cement base (SCB)

A soil-cement base contains higher proportion of cement than cement-modified soil. It is commonly used as a cheap pavement base for roads, streets, parking lots, airports, and material handling areas. Specialized equipment, such as a soil stabilizer and a mechanical cement spreader is usually required. A seal coat is required in order to keep

moisture Moisture is the presence of a liquid, especially water, often in trace amounts. Small amounts of water may be found, for example, in the air (humidity), in foods, and in some commercial products. Moisture also refers to the amount of water vapo ...

out. For uses as a

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of ...

construction material, a suitable surface coating, usually a thin layer of

asphalt concrete Asphalt concrete (commonly called asphalt, blacktop, or pavement in North America, and tarmac, bitumen macadam, or rolled asphalt in the United Kingdom and the Republic of Ireland) is a composite material commonly used to surface roads, parking ...

, is needed to reduce

wear Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology. Wear in ...

. In comparison with granular bases, soil cement bases can be thinner for the same road load, owing to their slab-like behavior that distributes load over broader areas. In-place or nearby located materials can be used for construction - locally found soil, stone, or reclaimed granular base from a road being reconstructed. This conserves both material and energy. The strength of soil-cement bases actually increases with age, providing good long-term performance.

Cement-treated base (CTB)

A cement-treated base is a mix of granular soil aggregates or aggregate material with Portland cement and water. It is similar in use and performance to soil-cement base.

Acrylic copolymer (Rhino Snot)

Developed for the U.S. Military in desert conditions and commercially trademarked, "Rhino Snot" is a water-soluble acrylic copolymer applied to soil or sand to penetrate and coat the surface. When dry, it forms a waterproof, UV-resistant, solid bond which binds the soil together, reducing dust. In higher concentrations, it creates a durable surface that can withstand heavy traffic, allowing existing soil to be used for roads, parking lots, trails and other heavy-traffic areas.

References