Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces the GB/T 20491-2006 Steel slag powder used for cement and concrete. In addition to a number of editorial changes, the following main technical changes have been made with respect to GB/T 20491-2006:
——"steel slag powder may be combined with granulated blast furnace slag powder and fly ash” in the scope is deleted;
——the definition of "comparison samples, inspected samples, comparison mortar, inspected mortar, activity index, fluidity ratio" in terms and definitions is deleted;
——"it is allowed to add an appropriate amount of gypsum as specified in GB/T 5483 and cement grinding process additives as specified in JC/T 667 during grinding.” in the definition of steel slag powder is modified to “it is allowed to add cement abrasives as specified in GB/T 26748 during grinding”;
——for the specific surface area of the steel slag powder, “the specific surface area of the primary and secondary grades shall be not less than 400m2/kg” is modified to “the specific surface area of the primary and secondary grades shall be ≥ 350m2/kg.” (see Table 1);
——"the density of steel slag powder is modified from “not less than 2.8g/cm3" to "≥3.2g/cm3";
——" the free calcium oxide content of steel slag powder is modified from “not more than 3.0%" to "≤4.0%";
——the definition and index of the alkalinity coefficient of steel slag powder is deleted;
——chlorine ion content index of steel slag powder is added, and the value ≤0.06%;
——the fluidity ratio is modified from “not less than 90” to “≥95”;
——The stability of steel slag powder in medium pressure autoclave method is modified from “shall be qualified when the MgO content in steel slag is greater than 13%” to “6h autoclave expansion rate ≤0.50% (if the MgO content in steel slag powder is not more than 5%, it is not necessary to inspect the autoclave stability)”;
——The reference method for the determination of free calcium oxide content is modified from "YB/T 140 Method of chemical analysis for steel slag" to "YB/T 4328 Method for the determination of content of free calcium oxide in steel slag";
——the determination of chlorine ion content is added;
——the test method of water content is modified from "as specified in GB/T 18046-2000, Annex B" to "as specified in GB/T 51003-2014, Annex C";
——the test method of activity index and fluidity ratio is modified from “as specified in Annex A” to “as specified in GB/T 51003-2014, Annex B”;
——the determination of stability is modified to “The autoclave test is carried out in accordance with GB/T 750, and the autoclave time is 6h. The boiling test is carried out in accordance with the requirements of test cake method in GB/T 1346”;
——the autoclave stability item is added in end-of-manufacturing inspection items;
——"in addition to the stability index, if any of them does not meet the requirements, the sampling shall be doubled, the unqualified items shall be re-inspected, and the results of the re-inspection shall be taken as the basis for evaluation. The activity index may be downgraded after re-inspection. If the stability is unqualified, it cannot be re-inspected, but as an unacceptable product” is added in the rejected product requirement in the judgment rules;
——the packaging is modified from "steel slag powder may be packaged in bags or bulk. The net mass of each bag shall not be less than 98% of the marked mass, and the total mass of 20 randomly sampled bags shall not be less than 20 times the marked mass” to “steel slag powder may be packaged in bags or bulk. The net mass of each bag is 50kg and shall not be less than 99% of the marked mass, and the total mass of 20 randomly sampled bags shall not be less than 1,000kg (including packaging bag). As for other packaging types, it shall be determined by the purchaser and the supplier through negotiation.";
——the Annex A is deleted.
This standard was proposed by China Iron and Steel Industry Association.
This standard is under the jurisdiction of SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
The previous edition of this standard is as follows:
——GB/T 20491-2006.
Steel slag powder used for cement and concrete
1 Scope
This standard specifies the terms and definitions, technical requirements, test method, inspection rules, packaging, marking, transportation and storage of steel slag powder used for cement and concrete.
This standard is applicable to steel slag powder used for cement and concrete
2 Normative references
The following referenced documents are indispensable for the application 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 208 Test method for determining cement density
GB/T 750 Test method for cement autoclave stability
GB/T 1346 Test method for water requirement of normal consistency, setting time and soundness of the Portland cement
GB/T 2419 Test method for fluidity of cement mortar
GB/T 8074 Testing method for specific surface of cement—Blaine method
GB 8076 Concrete Admixture
GB/T 9774 Sacks for packing cement
GB/T 12573 Sampling method for cement
GB/T 17671 Method of testing cements—Determination of strength
GB/T 51003-2014 Technical code for application of mineral admixture
YB/T 022 Steel slag used for cement
YB/T 804 Terminology for iron and steel slag & treatment and utilization
YB/T 4328 Method for the determination of content of free calcium oxide in steel slag
3 Terms and definitions
For the purposes of this document, the terms and definitions given in YB/T 804 and the following apply.
3.1
steel slag powder
product that is ground with a converter or electric furnace steel slag (abbreviated as steel slag) conforming to YB/T 022 to a certain fineness after magnetic separation and iron removal
4 Technical requirements
The technical requirements of steel slag powder shall meet the requirements of Table 1.
Table 1 Technical requirements
Items Primary grade Secondary grade
Specific surface area /(m2/kg) ≥350
Density /(g/cm3) ≥3.2
Water content (mass fraction)/% ≤1.0
Content of free calcium oxide (mass fraction)/% ≤4.0
Sulfur trioxide content (mass fraction)/% ≤4.0
Chlorine ions content (mass fraction)/%) ≤0.06
Activity index /% 7 d ≥65 ≥55
28 d ≥80 ≥65
Fluidity ratio /% ≥95
Stability Boiling test Qualified
Autoclave Test 6h autoclave expansion rate ≤ 0.50%a
a If the content of MgO in steel slag powder is not greater than 5%, the autoclave stability may not be inspected.
5 Test methods
5.1 Specific surface area
It shall be tested according to GB/T 8074.
5.2 Density
It shall be tested according to GB/T 208.
5.3 Water content
It shall be tested according to GB/T 51003-2014, Annex C.
5.4 Free calcium oxide
It shall be tested according to YB/T 4328.
5.5 Sulfur trioxide
It shall be tested according to GB/T 176.
5.6 Chlorine ions
It shall be tested according to GB/T 176.
5.7 Activity index and fluidity ratio
It shall be tested in accordance with GB/T 51003-2014, Annex B. Reinforce cement for performance inspection of concrete admixtures conforming to GB 8076 shall be adopted as the cement for inspection. Test specimen is made by mixing steel slag powder and reference cement at a mass ratio of 3:7.
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 Technical requirements
5 Test methods
6 Inspection rules
7 Packaging, marking, transportation and storage
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces the GB/T 20491-2006 Steel slag powder used for cement and concrete. In addition to a number of editorial changes, the following main technical changes have been made with respect to GB/T 20491-2006:
——"steel slag powder may be combined with granulated blast furnace slag powder and fly ash” in the scope is deleted;
——the definition of "comparison samples, inspected samples, comparison mortar, inspected mortar, activity index, fluidity ratio" in terms and definitions is deleted;
——"it is allowed to add an appropriate amount of gypsum as specified in GB/T 5483 and cement grinding process additives as specified in JC/T 667 during grinding.” in the definition of steel slag powder is modified to “it is allowed to add cement abrasives as specified in GB/T 26748 during grinding”;
——for the specific surface area of the steel slag powder, “the specific surface area of the primary and secondary grades shall be not less than 400m2/kg” is modified to “the specific surface area of the primary and secondary grades shall be ≥ 350m2/kg.” (see Table 1);
——"the density of steel slag powder is modified from “not less than 2.8g/cm3" to "≥3.2g/cm3";
——" the free calcium oxide content of steel slag powder is modified from “not more than 3.0%" to "≤4.0%";
——the definition and index of the alkalinity coefficient of steel slag powder is deleted;
——chlorine ion content index of steel slag powder is added, and the value ≤0.06%;
——the fluidity ratio is modified from “not less than 90” to “≥95”;
——The stability of steel slag powder in medium pressure autoclave method is modified from “shall be qualified when the MgO content in steel slag is greater than 13%” to “6h autoclave expansion rate ≤0.50% (if the MgO content in steel slag powder is not more than 5%, it is not necessary to inspect the autoclave stability)”;
——The reference method for the determination of free calcium oxide content is modified from "YB/T 140 Method of chemical analysis for steel slag" to "YB/T 4328 Method for the determination of content of free calcium oxide in steel slag";
——the determination of chlorine ion content is added;
——the test method of water content is modified from "as specified in GB/T 18046-2000, Annex B" to "as specified in GB/T 51003-2014, Annex C";
——the test method of activity index and fluidity ratio is modified from “as specified in Annex A” to “as specified in GB/T 51003-2014, Annex B”;
——the determination of stability is modified to “The autoclave test is carried out in accordance with GB/T 750, and the autoclave time is 6h. The boiling test is carried out in accordance with the requirements of test cake method in GB/T 1346”;
——the autoclave stability item is added in end-of-manufacturing inspection items;
——"in addition to the stability index, if any of them does not meet the requirements, the sampling shall be doubled, the unqualified items shall be re-inspected, and the results of the re-inspection shall be taken as the basis for evaluation. The activity index may be downgraded after re-inspection. If the stability is unqualified, it cannot be re-inspected, but as an unacceptable product” is added in the rejected product requirement in the judgment rules;
——the packaging is modified from "steel slag powder may be packaged in bags or bulk. The net mass of each bag shall not be less than 98% of the marked mass, and the total mass of 20 randomly sampled bags shall not be less than 20 times the marked mass” to “steel slag powder may be packaged in bags or bulk. The net mass of each bag is 50kg and shall not be less than 99% of the marked mass, and the total mass of 20 randomly sampled bags shall not be less than 1,000kg (including packaging bag). As for other packaging types, it shall be determined by the purchaser and the supplier through negotiation.";
——the Annex A is deleted.
This standard was proposed by China Iron and Steel Industry Association.
This standard is under the jurisdiction of SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
The previous edition of this standard is as follows:
——GB/T 20491-2006.
Steel slag powder used for cement and concrete
1 Scope
This standard specifies the terms and definitions, technical requirements, test method, inspection rules, packaging, marking, transportation and storage of steel slag powder used for cement and concrete.
This standard is applicable to steel slag powder used for cement and concrete
2 Normative references
The following referenced documents are indispensable for the application 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 208 Test method for determining cement density
GB/T 750 Test method for cement autoclave stability
GB/T 1346 Test method for water requirement of normal consistency, setting time and soundness of the Portland cement
GB/T 2419 Test method for fluidity of cement mortar
GB/T 8074 Testing method for specific surface of cement—Blaine method
GB 8076 Concrete Admixture
GB/T 9774 Sacks for packing cement
GB/T 12573 Sampling method for cement
GB/T 17671 Method of testing cements—Determination of strength
GB/T 51003-2014 Technical code for application of mineral admixture
YB/T 022 Steel slag used for cement
YB/T 804 Terminology for iron and steel slag & treatment and utilization
YB/T 4328 Method for the determination of content of free calcium oxide in steel slag
3 Terms and definitions
For the purposes of this document, the terms and definitions given in YB/T 804 and the following apply.
3.1
steel slag powder
product that is ground with a converter or electric furnace steel slag (abbreviated as steel slag) conforming to YB/T 022 to a certain fineness after magnetic separation and iron removal
4 Technical requirements
The technical requirements of steel slag powder shall meet the requirements of Table 1.
Table 1 Technical requirements
Items Primary grade Secondary grade
Specific surface area /(m2/kg) ≥350
Density /(g/cm3) ≥3.2
Water content (mass fraction)/% ≤1.0
Content of free calcium oxide (mass fraction)/% ≤4.0
Sulfur trioxide content (mass fraction)/% ≤4.0
Chlorine ions content (mass fraction)/%) ≤0.06
Activity index /% 7 d ≥65 ≥55
28 d ≥80 ≥65
Fluidity ratio /% ≥95
Stability Boiling test Qualified
Autoclave Test 6h autoclave expansion rate ≤ 0.50%a
a If the content of MgO in steel slag powder is not greater than 5%, the autoclave stability may not be inspected.
5 Test methods
5.1 Specific surface area
It shall be tested according to GB/T 8074.
5.2 Density
It shall be tested according to GB/T 208.
5.3 Water content
It shall be tested according to GB/T 51003-2014, Annex C.
5.4 Free calcium oxide
It shall be tested according to YB/T 4328.
5.5 Sulfur trioxide
It shall be tested according to GB/T 176.
5.6 Chlorine ions
It shall be tested according to GB/T 176.
5.7 Activity index and fluidity ratio
It shall be tested in accordance with GB/T 51003-2014, Annex B. Reinforce cement for performance inspection of concrete admixtures conforming to GB 8076 shall be adopted as the cement for inspection. Test specimen is made by mixing steel slag powder and reference cement at a mass ratio of 3:7.
Contents of GB/T 20491-2017
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 Technical requirements
5 Test methods
6 Inspection rules
7 Packaging, marking, transportation and storage
