readymixed

Readymixed concrete, or ready-mix concrete, is concrete manufactured in a central batching plant according to a prescribed mix design and delivered to a construction site in a plastic or freshly mixed state for placement. It is distinguished from site-mixed concrete, where materials are combined on site.

A typical readymixed concrete recipe includes cementitious materials (such as Portland cement or blended cements), aggregates (sand and gravel or crushed stone), water, and admixtures to modify performance. Admixtures can improve workability, accelerate or retard setting, control temperature, or introduce air for durability. Plants perform precise batching under quality control systems, with trial mixes, slump tests, air content checks, and compression tests on test cylinders to verify strength and compliance with specifications.

Delivery is usually by truck-mounted or agitator mixers that keep the concrete in motion to prevent setting during transport. For difficult layouts or tall structures, concrete may be pumped through hoses or pipelines. Transit time, temperature, and mixing consistency are important for maintaining workability from batching to placement.

Applications include concrete slabs, columns, foundations, walls, pavements, and other structural elements in buildings, bridges, and infrastructure. Advantages of readymixed concrete include consistent quality, improved on-site productivity, reduced labor and waste, and better control of materials and air content. Limitations include dependence on timely delivery, sensitivity to delays and temperature changes, potential for segregation if not handled properly, and higher transportation costs for distant sites.

Standards and quality control vary by region but commonly reference specifications such as ASTM C94 in the United States or EN 206 in many other markets. Environmentally, readymixed plants can use supplementary cementitious materials and implement washout and recycling practices to reduce waste and emissions.