Length Change of Restrained Expansion of Mortar and Concrete

Length Change of Restrained Expansion of Mortar and Concrete apparatus is a precision laboratory system designed to evaluate dimensional changes and restrained expansion in cement, mortar, and concrete mixtures under controlled conditions. It allows accurate assessment of cement additives, expansive agents, or mix designs that influence volumetric changes during setting and early-age hardening.

The apparatus uses specially machined steel molds in a triple-prism configuration. Each mold is equipped with restraining rods that limit free expansion, creating a controlled axial deformation environment to realistically capture internal stress behavior. Smooth end plates ensure uniform restraint along the specimen length, providing high measurement accuracy and mold stability during long-term testing.

The system accommodates standard mortar prisms (50×50×250 mm) and concrete prisms (80×80×240 mm). Digital or analog length comparators measure expansion with micron-level precision. Comparator contact points are compatible with standard reference bars, enabling detection of minute differences in expansion rates between mixtures.

All components are ergonomically designed for repeated laboratory use. Quick-release fasteners allow easy mold cleaning and assembly. Optional accessories include spare end plates, restraining rods, reference bars, and transport fixtures. The device ensures reliable, repeatable, and standards-compliant evaluation of restrained expansion behavior in cementitious materials.