GB/T 25177-2010Recycled coarse aggregate for concrete (English PDF)

3.1 Recycled coarse aggregate for concrete

Particles with a size greater than 4.75 mm, processed from construction and demolition waste - such as concrete, mortar, stone, and brick/tile - and used for the preparation of concrete.

3.2 Content of fine powder

The content of particles with a particle size of less than 75 µm in recycled fine aggregate.

3.3 Content of clay lump

The content of particles in recycled coarse aggregate for concrete that - while originally larger than 4.75 mm in size - break down into particles smaller than 2.36 mm after water immersion and manual crushing.

3.4 Elongated and flaky particle

For recycled coarse aggregate for concrete, particles with a length exceeding 2.4 times the average particle size of their respective size fraction are classified as elongated (needle-like) particles, while those with a thickness less than 0.4 times the average particle size are classified as flaky (plate-like) particles (where the average particle size refers to the mean of the upper and lower size limits of that fraction).

3.5 Crushing index

An indicator of the resistance to crushing of recycled coarse aggregate for concrete.

3.6 Soundness

The ability of recycled coarse aggregate for concrete to resist breakage under the influence of natural weathering and other physicochemical factors.

3.7 Apparent density

The mass per unit volume of recycled coarse aggregate for concrete (including internal closed pores).

3.8 Water absorption

The mass of water contained in recycled coarse aggregate for concrete in the saturated surface-dry state, expressed as a percentage of its oven-dry mass.

3.9 Impurities

Substances other than concrete, mortar, brick/tile, and stone found in recycled coarse aggregate for concrete.

4.1 Classification

Recycled coarse aggregates for concrete (hereinafter referred to as recycled coarse aggregates) are classified into Class I, Class II, and Class III based on performance requirements.

4.2 Specifications

Recycled coarse aggregates are classified into continuous grading and single-size grading based on particle size. Continuous grading comprises four specifications. 5 mm~16 mm, 5 mm~20 mm, 5 mm~25 mm, and 5 mm~31.5 mm; single-size grading comprises three specifications. 5 mm~10 mm, 10 mm~20 mm, and 16 mm~31.5 mm. constitutes a batch. For a daily output exceeding 5000 t, every 2000 t constitutes a batch, and any remaining amount less than 2000 t also constitutes a batch. For construction and demolition waste from the same source with a daily output of less than 600 t, a single inspection batch may be defined based on continuous production not exceeding three days and a total quantity not exceeding 600 t.

7.3 Determination rules

7.3.1 Upon inspection (including re-inspection), the product may be deemed qualified if all parameters meet the requirements specified for the corresponding category in this standard.

7.3.2 If any performance indicator fails to meet the requirements of this Standard, double the number of samples shall be drawn from the same batch of products to re-examine the non-compliant item(s). If the re-examination results comply with this Standard, the product shall be deemed qualified; if the results still fail to comply, the product shall be deemed unqualified.

8.1 Marks

Exit-factory products should provide product quality certificates, including.

a) Name, category, specifications, and manufacturer information (company name, address, telephone number, etc.) of the recycled coarse aggregate;

b) Batch number and supplied quantity;

c) Test results, date, and applicable standards;

d) Certificate of conformity number and date of issuance;

e) Signatures and/or stamps of the testing department and testing personnel; f) Precautions, etc.

8.2 Storage

During storage, recycled coarse aggregates should be stockpiled separately according to category and specification, so as to prevent crushing by traffic and product contamination.

8.3 Transportation

During transport, transport equipment such as vehicles and vessels must be thoroughly cleaned, and measures taken to prevent the inclusion of impurities and the dispersal of […]