kernelsand

Kernelsand is a granular composite material used in construction and materials science. It consists of silica sand grains bound together by a polymeric or bio-based binder to form a cohesive, porous matrix. The term is used in industrial and academic contexts to describe a class of sand-based granules designed for lightweight, insulated, and potentially recyclable building components.

Composition and production methods vary, but standard formulations blend roughly 60–75% silica sand with 20–35% binder and 5–15% functional additives such as surfactants, coupling agents, or short fibers. The material is produced by mixing, pelletizing or extruding, followed by curing or vulcanization. Bound granules are screened to achieve a target size distribution suitable for their intended use.

Properties of kernelsand depend on the specific formulation but often include a density range of about 1.4–1.9 g/cm3, and a compressive strength in the 8–25 MPa range. Thermal conductivity typically lies around 0.6–1.2 W/mK, influenced by porosity and binder type. Porosity of about 25–40% supports acoustic damping and reduced weight. Chemical stability is generally good, and environmental performance improves with bio-based binders, though recyclability depends on material composition and processing.

Applications encompass lightweight precast concrete aggregates, insulating panels, filtration media for liquids and gases, and horticultural substrates where drainage and aeration are important. Variants can be engineered with graded porosity and surface treatments, enabling integration with standard cementitious systems and modular construction approaches.

Development emerged in the early 2010s through collaborations between academic researchers and industry laboratories, with several regional producers marketing kernelsand under different trade names. Ongoing research focuses on lifecycle assessment, recyclability, and optimization of porosity and strength.

See also: lightweight aggregates, porous concrete, sand-based composites, bio-based binders.