This standard is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.
This document replaces GB/T 27690-2011 Silica fume for cement mortar and concrete. In addition to structural adjustments and editorial changes, the following main technical changes have been made with respect to GB/T 27690-2011:
a) The term and definition of silica fume slurry have been deleted (see Clause 3 of 2011 edition);
b) The terms and definitions of non-densified silica fume and densified silica fume have been added (see Clause 3);
c) The classification of silica fume by silicon dioxide content and bulk density has been added, and the classification of silica fume by service state has been deleted (see Clause 4 hereof; Clause 4 of 2011 edition);
d) The technical requirements for silica fume bulk density and residue on 45μm square-hole sieve have been added (see Clause 5);
e) The technical requirements for Grade 90 silica fume have been added (see Clause 5);
f) The technical requirements for silica fume slurry have been deleted (see Clause 5 of 2011 edition);
g) The technical requirements for loss on ignition, total alkali content and chloride ion content of silica fume have been modified (see Clause 5 hereof; Clause 5 of 2011 edition);
h) The test methods for bulk density and residue on 45μm square-hole sieve have been added (see Clause 6 and Annex A);
i) The test method for solid content has been deleted (See Clause 6 and Annex A of 2011 edition);
j) The requirements for water reducers for chloride ion penetration resistance tests and water reducers for activity index tests have been modified (see Clause 6 and Annex B hereof; Clause 6 and Annex B of 2011 edition);
k) The batch number and end-of-manufacturing inspection items have been modified (see Clause 7 hereof; Clause 7 of 2011 edition);
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This document was proposed by China Building Materials Federation.
This document is under the jurisdiction of the National Technical Committee on Cement Products of Standardization Administration of China (SAC/TC 197).
This document was firstly issued in 2011; and this edition is the first revision.
Silica fume for cement mortar and concrete
1 Scope
This document specifies the classification and designation, requirements, test methods, inspection rules, packaging, labeling, transportation and storage of silica fume for cement mortar and concrete.
This document applies to silica fume for cement mortar and concrete.
2 Normative reference
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 176 Methods for chemical analysis of cement
GB/T 1345 The test sieving method for fineness of cement
GB/T 2419 Test method for fluidity of cement mortar
GB 6566 Limits of radionuclides in building materials
GB 8076 Concrete admixtures
GB/T 17671 Test method of cement mortar strength (ISO method)
GB/T 19587 Determination of the specific surface area of solids by gas adsorption using the BET method
GB/T 50082 Standard for test methods of long-term performance and durability of ordinary concrete
JC/T 681 Mixer for mixing mortars
JGJ 63 Standard of water for concrete
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
silica fume
powder material with amorphous silicon dioxide as the main component, which is obtained by collecting the silicon vapor discharged from the flue, when smelting ferrosilicon alloy or silicon metal
3.2
non-densified silica fume
silica fume with bulk density of not more than 350 kg/m3, which is obtained by collecting directly without densification
3.3
densified silica fume
silica fume with bulk density of more than 350 kg/m3 after the non-densified silica fume is densified
4 Classification and designation
4.1 Product classification
4.1.1 The product may be classified by silicon dioxide content into Grade 85 silica fume (Code: SF85) and Grade 90 silica fume (Code: SF90).
4.1.2 It may also be classified by bulk density into non-densified silica fume (Code: R) and densified silica fume (Code: D).
4.2 Product designation
Product designation consists of the classification codes of silicon dioxide content and bulk density and the standard number.
For example, the designation of Grade 90 densified silica fume is as follows:
SF90-D GB/T 27690.
Foreword i
1 Scope
2 Normative reference
3 Terms and definitions
4 Classification and designation
5 Requirements
6 Test methods
7 Inspection rules
8 Packaging, labeling, transportation and storage
Annex A (Normative) Test method for bulk density
Annex B (Normative) Test methods for water demand ratio and activity index
Annex C (Normative) Test method for inhibiting alkali-aggregate reactivity
