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This standard is a revision on the basis of JC 714-87(96) (the former standard serial number: ZBQ11005-87) Rapid Hardening Sulphoaluminate Cement. In this revision, the Foreword and the Grades 625 and 725 are added; upon test and study, the requirements for free calcium oxide and 12h strength are canceled; the specific surface area index is revised, and the inspection rules, packaging mass and printed marks are revised according to the Amendments 1 of GB 175-92 and GB 1344-92.
This standard replaces JC 714-87(96) (i.e., ZBQ11005-87) Rapid Hardening Sulphoaluminate Cement from the effective date.
This standard is under the jurisdiction of the National Technical Committee on Cement of Standardization Administration of China.
This standard was issued in 1987 for the first time.
1 Scope
This standard specifies definitions, requirements, test methods, inspection rules, and packaging, marking, transportation and storage of rapid hardening sulphoaluminate cement.
This standard is applicable to the production and inspection of rapid hardening sulphoaluminate cement.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. At time of publication, the editions indicated were valid. All standards are subject to revision, and all parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.
GB 177-85 Test Method for Strength of Hydraulic Cement Mortar
GB 1346-89 Test Methods for Water Requirement of Normal Consistency, Setting Time and Soundness of the Portland Cement
GB 2419-94 Test Method for Fluidity of Cement Mortar
GB/T 5483-1996 Gypsum and Anhydrite
GB 8074-87 Testing Method for Specific Surface of Cement - Blaine Method
GB 9774-1996 Sacks for Packing Cement
GB 12573-90 Sampling Method for Cement
3 Definitions
The hydraulic cementing material with high early strength and made of appropriate amount of gypsum, limestone of 0~10% and the clinker (consisting of main mineral components such as dicalcium silicate and anhydrous sulphoaluminate obtained by calcining appropriate raw materials) by grinding is referred to as the rapid hardening ferri-aluminate cement , coded as R·SAC.
The gypsum contained in the cement shall meet the requirements of Grade A1 or G2 and above in GB/T 5483, and the content of Al2O3 in the limestone shall not be more than 2.0%.
4 Grades
There are four compressive strength grades, i.e., 425, 525, 625 and 725, for cement at the age of 3d.
5 Requirements
5.1 The specific surface area and setting time shall be in accordance with those specified in Table 1.
Table 1
Item Index value
Specific surface area, m2/kg ≥ 350
Setting time
min Initial setting not earlier than 25
Final setting not later than 180
Note: The setting time may be changed as requested by the user.
5.2 The age strength of cement shall not be less than the corresponding values given in Table 2.
Table 2 MPa
Grade Compressive strength Bending strength
1d 3d 28d 1d 3d 28d
425 34.5 42.5 48.0 6.5 7.0 7.5
525 44.0 52.5 58.0 7.0 7.5 8.0
625 52.5 62.5 68.0 7.5 8.0 8.5
725 59.0 72.5 78.0 8.0 8.5 9.0
6 Test Methods
6.1 Specific surface area
The test shall be carried out according to GB 8074.
6.2 Setting time
The test shall be carried out according to GB 1346.
6.3 Strength
The test shall be carried out according to GB 177, but with the following supplements and requirements:
a) The water consumption shall be determined per a water-cement ratio of 0.42 (227mL) and a cement mortar fluidity of 121~130mm. When the fluidity of the cement mortar prepared according to a water-cement ratio of 0.42 exceeds the specified range, the water-cement ratio shall be increased or decreased by an integral multiple of 0.01 to make the fluidity be within the specified range. The fluidity of the cement mortar shall be determined according to GB 2419.
b) After being formed, the test piece, together with the mould, shall be placed in a curing box with a temperature of 20℃±3℃ and a humidity of more than 90% and cured for 4h, and then be subject to demoulding (if the demoulding is difficult to achieve, the demoulding time may be appropriately extended), and the test piece shall be finally cured in water with a temperature of 20℃±2℃.
c) For the 1d and 3d test pieces, they shall be subject to strength test within the specified age ±1h.
Foreword II
1 Scope
2 Normative References
3 Definitions
4 Grades
5 Requirements
6 Test Methods
7 Inspection Rules
8 Packaging, Marking, Transportation and Storage
