Sandcrete is a yellow-white

building material Building material is material used for construction. Many naturally occurring substances, such as clay, rock (geology), rocks, sand, wood, and even twigs and leaves, have been used to construct buildings. Apart from naturally occurring materia ...

made from a binder (typically

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 c ...

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

in a ratio of circa 1:8, and water. Sometimes other ingredients may be added to reduce the amount of expensive Portland cement such as

pozzolana Pozzolana or pozzuolana ( , ), also known as pozzolanic ash ( la, pulvis puteolanus), is a natural siliceous or siliceous- aluminous material which reacts with calcium hydroxide in the presence of water at room temperature (cf. pozzolanic reactio ...

s and

rice husk ash Rice hulls (or rice husks) are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, or fuel. Rice hulls are p ...

. Sandcrete is similar but weaker than mortar, for which the ratio is circa 1:5. ''

Soil cement Soil cement is a construction material, a mix of pulverized natural soil with small amount of portland cement and water, usually processed in a tumbler, compacted to high density. Hard, semi-rigid durable material is formed by hydration of the ce ...

'' and ''landcrete'' are similar materials but use other types of

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 te ...

and hydraform blocks which are compressed, stabilized,

earth block A compressed earth block (CEB), also known as a pressed earth block or a compressed soil block, is a building material made primarily from an appropriate mix of fairly dry inorganic subsoil, non-expansive clay, sand, and aggregate. Forming compr ...

s. Sandcrete is usually used as hollow rectangular blocks similar to

concrete masonry unit A concrete masonry unit (CMU) is a standard-size rectangular block used in building construction. CMUs are some of the most versatile building products available because of the wide variety of appearances that can be achieved using them. Tho ...

s, often wide, thick, and with hollows that run from top to bottom and occupy around one third of the volume of the block. The blocks are joined together with mortar.

Strength and usage

The final

compressive strength In mechanics, compressive strength or compression strength is the capacity of a material or structure to withstand loads tending to reduce size (as opposed to tensile strength which withstands loads tending to elongate). In other words, compre ...

of sandcrete can be as high as 4.6 N/mm², which is much less than

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...

's 40 N/mm². Sandcrete is unsuitable for load-bearing columns, and is mainly used for walls, or for foundations if no suitable alternative is available. As material for walls, its strength is less than that of fired clay bricks, but sandcrete is considerably cheaper. Sandcrete is the main building material for walls of single-storey buildings (such as houses and schools) in countries such as Ghana and Nigeria. Research has shown using organic ash to replace Portland cement, which is better than simply using less Portland cement.

Coarse aggregate

Addition of coarse aggregates has been tried, since this is a cheap way to increase compressive strength, but since the cement content of sandcrete is small, so is the amount of water that is added to the sand/cement mix to cure it. Adding more solid materials makes the mix much less fluid, making it difficult to cast into blocks.

References

{{reflist Soil-based building materials Cement Masonry