Code of Practice Ready-Mixed Concrete
2003 Edition

IS 4926 specifies that batching equipment must maintain weighing tolerances of ±2% for cement and mineral admixtures and ±3% for aggregates, water, and chemical admixtures. Scale increments should not exceed 5 kg for cement (analogue) and 25 kg for aggregates, with digital scales having finer increments. Calibration accuracy limits are ±0.25% at installation or reconditioning and ±0.5% during routine operation. Systems must be zeroed and tared daily, prevent material buildup, and maintain documented calibration records including corrective actions.

Water content must be controlled by monitoring workability (such as slump) and adjusting for moisture in aggregates, with all quantities recorded in production logs. Admixtures should be measured accurately by volume or mass, with recording of dosage amounts. Any additional admixture applied on-site requires prior agreement. Measurement accuracy follows ±2% for cement and mineral admixtures and ±3% for aggregates, water, and chemical admixtures. Automatic batching systems must ensure scales are zeroed and hoppers tared before use.

Producers must perform random sampling of concrete from major batches at a frequency of at least one sample per 50 m³ or 50 batches. For each sample, three specimens are prepared and tested for 28-day compressive strength using IS 14858-compliant machines. Optional early strength tests at 72 hours or 7 days may be conducted for preliminary assessment. Test results are continuously monitored to compare actual strength against targets, with necessary adjustments to mix proportions made promptly if deviations occur. Additional tests for workability, density, temperature, and air content support quality assurance.

Producers are required to maintain safe working environments that prioritize employee health and safety. Traffic routes must be planned to avoid sensitive areas, minimize fuel consumption, and keep vehicles clean, preventing concrete spills on public roads. Water management involves reducing usage and waste while complying with effluent discharge regulations. Measures to prevent fuel, oil, and chemical spills must be in place to protect surface and groundwater quality. These practices ensure environmental protection and worker safety throughout production and logistics.

The delivery ticket, which must be preprinted and issued prior to discharge, should include the mix code and grade (characteristic strength), delivery ticket number, batching and loading date and time, volume of concrete delivered, estimated slump, total water added, cement content, type and quantity of mineral additives, maximum water-cement ratio, nominal aggregate size, cement type and grade if specified, admixtures used, maximum concrete temperature at delivery, and any special instructions. This documentation ensures traceability, quality assurance, and contractual clarity.