NHBC Standards 2010

2.1 Concrete and its reinforcement


2.1 - M1Material standards
2.1 - M2Ready-mixed concrete
2.1 - M3Site-mixed concrete
2.1 - M4Reinforcement

2.1 - M1
All materials shall:
(a) meet the Technical Requirements
(b) take account of the design

Materials that comply with the design and the guidance below will be acceptable for concrete and its reinforcement.

Materials for concrete and its reinforcement should comply with all relevant standards, including those listed below. Where no standard exists, Technical Requirement R3 applies (see Chapter 1.1 'Introduction to the Standards and Technical Requirements').

References to British Standards and Codes of Practice include those made under the Construction Products Directive (89/106/EEC) and, in particular, appropriate European Technical Specifications approved by a European Committee for Standardisation (CEN).


2.1 - M2
Ready-mixed concrete shall be in accordance with the design and shall be chosen to ensure sufficient strength and durability

Ready-mixed concrete should be ordered to a detailed specification conforming to BS 8500 and BS EN 206-1.

When Designated mixes are used, the ready-mix supplier will only require the mix designation, and consistence class.


2.1 - M3
Materials for site-mixed concrete shall be in accordance with the design and shall be chosen to ensure sufficient strength and durability

Items to be taken into account include:

(a) cement or cementitious material

Cement and combination and combination types should be as:

Table 1 of BS 8500-2 and should conform to the Standards quoted therein and in the case of combinations to Annex A of BS 8500-2.

(b) aggregates

Aggregates should comply with:

BS EN 12620 Aggregates for concrete.

Aggregates should consist of any types of coarse and/or fine aggregate as specified. Aggregates supplied as a mixture of different sizes should be proportioned to ensure a reasonable consistency.

Certain types of aggregate are shrinkable and require special precautions in mixing as described in BRE Digest 357.

Certain types of aggregate may be susceptible to alkali attack or excessive moisture movement. Unfamiliar materials should be checked and precautions taken, where necessary. Aggregate Carbon Range (ACR) should not exceed the specified limits if required for use in concrete subject to aggressive sulfate ground conditions.

Proprietary aggregates should only be specified where they have been assessed in accordance with Technical Requirement R3.

(c) water

Water from the mains is acceptable. Water from other sources should meet:

BS EN 1008 Mixing water for concrete.

(d) admixtures

Admixtures, other than air-entraining admixtures, should comply with:

BS EN 934-2 Admixtures for concrete mortar and grout - Concrete admixtures - Definitions, requirements, conformity, marking and labelling.

Air entraining admixtures should not be used in Standardized Prescribed concrete mixes.


2.1 - M4
Reinforcement shall be in accordance with the design

Reinforcement should comply with:

BS 4449Specification for carbon steel bars for the reinforcement of concrete
BS 4482Specification for cold reduced steel wire for the reinforcement of concrete
BS 4483Specification for steel fabric for the reinforcement of concrete
BS 6744Specification for austenitic stainless steel bars for the reinforcement of concrete.