GB/T 21120-2018Synthetic fibres for cement cement concrete and mortar (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 21120-2007 "synthetic fibers for cement concrete and mortar". Compared with GB/T 21120-2007, except The main technical changes outside the editorial changes are as follows.

---Adjusted the standard fiber range (see Chapter 1, Chapter 1 of the 2007 edition);

--- Adjusted some of the normative references (see Chapter 2, Chapter 2 of the 2007 edition);

--- Terms and definitions increase polyformaldehyde fiber, linear density, etc. (see 3.6 and 3.20);

--- Product classification adds polyoxymethylene fibers (see 4.1);

--- Simplified product marking (see 4.3, 4.3 of the 2007 edition);

--- Increase the specification and measurement method of the moisture content of synthetic fibers (see 5.4 and 6.2);

--- Revised the fiber related parameter indicators of Table 2 (see Table 2, Table 2 of the 2007 edition);

--- Revised the provisions of Table 3 for the bending toughness of coarse fiber concrete (see Table 3, Table 3 of the 2007 edition);

--- Removed the provisions of the concrete penetration height ratio in Table 3 (see Table 3, Table 3 of the 2007 edition);

--- Revised the number of tests required in Table 4 (see Table 4, Table 4 of the 2007 edition);

--- Revised the requirements of standard factory inspection and type inspection (see 7.1 and 7.2, 2007 editions 7.1 and 7.2);

--- Added the main performance parameters of Appendix A synthetic fiber (see Appendix A);

--- Added the method for determining the diameter of the crude fiber in Appendix B (see Appendix B);

--- Increased the test method for the crack reduction coefficient of mortar in Appendix E (see Appendix E);

--- Added Appendix F fiber concrete flexural toughness test method (see Appendix F);

--- Revised the test method for the alkali resistance of synthetic fibers (see Appendix D, Appendix B of the 2007 edition);

--- Revised the impact test height (see Appendix G, Appendix C of the 2007 edition).

1 Scope

This standard specifies the terms and definitions, classification, requirements, test methods, inspection rules, signs, and synthetic fibers for cement concrete and mortar. Factory, packaging, transportation, storage, etc.

This standard applies to synthetic fibers for cement concrete and mortar. This standard does not apply to polyester fibers.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB 175 universal Portland cement

GB 8076 concrete admixture

GB/T 8170 Numerical Rounding Rules and Representation and Determination of Limit Values

GB/T 10685 wool fiber diameter test method projection microscope method

GB/T 14344 Test method for tensile properties of chemical fiber filaments

GB/T 14684 construction sand

GB/T 14685 construction with pebbles and gravel

GB/T 50080 Standard Test Method for Performance of Concrete Mixtures

GB/T 50081 Standard test method for mechanical properties of ordinary concrete

JC/T 474-2008 mortar, concrete waterproofing agent

JGJ55 general concrete mix design procedure

JGJ63 concrete water standard

JGJ70 building mortar basic performance test method standard

3 Terms and definitions

The following terms and definitions apply to this document.