- The HBM producer must have an established and maintained quality manual describing policy and procedures for production control in accordance with the production control annex of BS EN 14227 and as follows.
Tests & checks before and during production
- Constituents sourced off-site require monthly certification (or by delivery for cement etc); aggregates to BS EN 13242, cement to BS EN 197, fly ash to BS EN 14227-4 and GBS and GGBS to BS EN14227-2 Annex A.
- In accordance with BS EN 14277, and using the mixing plant’s automated surveillance and data collection system where appropriate, characteristics that require control during production include:
- pre-production properties of the constituents including plasticity, water content, and freedom from frozen agglomerations
- proportioning of the constituents including added water
- grading of the fresh mixture
- water content of the fresh mixture
- time of production
- temperature at production
- The proportioning must comply with the requirements of the target composition of the mixture.
- The above tests and checks must be carried out daily and recorded.
Laboratory mechanical performance tests
- Each day of production, or as detailed in the Quality Manual/Method Statement, the producer must sample the HBM for compliance with the compressive strength of Table A10.7 Sampling must be in accordance with BS 1924-1.
- Cubic or cylindrical specimen manufacture, curing and testing for compressive strength must be in accordance with Table A10.7. Cubes for compression testing must be 150 mm nominal size.
- A representative sub-sample must be taken from each sample for the determination of water content in accordance with BS 1924-2. Sampling must be in accordance with BS 1924-1.
Table A10.7 Compressive strength testing requirements for HBMs Cement used Specimen manufacture, nominal wet density & curing regime Curing temperature Test method for determination of RC Age at test Yes BS 1924-2 and BS EN 13286-41 20ºC BS EN 13286-41 28 days (See note) No 40ºC Note: For control purposes, HBM may be assessed on the basis of 7-day or other early age strength, provided that a correlation is established between the early age and 28-day strength