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GB 20472-2006: [GB/T 20472-2006] Sulphoaluminate cement
GB 20472-2006 (Renamed to GB/T 20472-2006)
GB
NATIONAL STANDARD OF THE
PEOPLE?€?S REPUBLIC OF CHINA
ICS 91.100.10
Q 11
GB 20472-2006
Sulphoaluminate cement
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ISSUED ON: AUGUST 25, 2006
IMPLEMENTED ON: FEBRUARY 01, 2007
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
This standard was converted into recommended standard,
from March 23, 2017. It was numbered as GB/T 20472-2006.
Table of Contents
Foreword ... 3??
1 Scope ... 5??
2 Normative references ... 5??
3 Terms and definitions ... 6??
4 Components ... 7??
5 Grades ... 7??
6 Technical requirements ... 8??
7 Test methods ... 9??
8 Inspection rules ... 11??
9 Packaging, marking, transportation, storage, use ... 13??
Appendix A (normative) Technical requirements for sulphoaluminate cement
clinker ... 15??
Appendix B (Normative) Method for determination of alkalinity of low alkalinity
sulphoaluminate cement ... 16??
Sulphoaluminate cement
1 Scope
This standard specifies the terms and definitions, constituent materials,
strength grades, self-stress grades, technical requirements, test methods,
inspection rules, packaging, marking, transportation, storage of
sulphoaluminate cement.
This standard applies to sulphoaluminate cement.
2 Normative references
The provisions in following documents become the provisions of this Standard
through reference in this Standard. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this Standard;
however, parties who reach an agreement based on this Standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 205 Test method for analysis of high alumina cement
GB/T 1346-2001 Test methods for water requirement of normal consistency,
setting (eqv ISO 9597:1989)
GB/T 2419-2005 Test method for fluidity of cement mortar
GB/T 5483-1996 Gypsum and anhydrite (eqv ISO 1587:1975)
GB 9774 Sacks for packing cement
GB/T 12573 Sampling method for cement
GB/T 17671-1999 Method of testing cements - Determination of strength (idt
ISO 679:1989)
JC/T 313-1982 (1996) Test method for determining expansive ratio of
expansive cement
JC/T 453 Method of physical test for self-stressing cement
JC/T 681 Mixer for mixing mortars
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Sulphoaluminate cement
A hydraulic cementing material, which is obtained by finely grinding the
cement clinker -- using anhydrous calcium sulphoaluminate and dicalcium
silicate as the main mineral components, which is obtained by calcining the
raw materials of appropriate composition -- by mixing with different amounts
of limestone and appropriate amount of gypsum. Sulphoaluminate cement
is divided into rapid hardening sulphoaluminate cement, low alkalinity
sulphoaluminate cement, self-stressing sulphoaluminate cement.
3.2
Rapid hardening sulphoaluminate cement
A hydraulic cementitious material, with high early strength, which is obtained
by finely grinding the sulphoaluminate cement clinker of appropriate
composition, a small amount of limestone, an appropriate amount of gypsum.
It is coded R ?€? SAC.
Note: The amount of limestone added shall not exceed 15% of the cement mass.
3.3
Low alkalinity sulphoaluminate cement
A hydraulic cementitious material with low alkalinity, which is obtained by
finely grinding the sulphoaluminate cement clinker of appropriate
composition, a large amount of limestone, an appropriate amount of gypsum.
It is coded L ?€? SAC.
Note: The amount of limestone added shall not be less than 15% of the cement
mass AND not greater than 35% of the cement mass. Low alkalinity
sulphoaluminate cement is mainly used to make glass fiber reinforced cement
products. When used for concrete products and structures, such as steel fibers,
steel bars, steel meshes, steel embedded parts, the steel used shall be stainless
steel.
3.4
Self-stressing sulphoaluminate cement
6.1 and 8.2:
a) The water consumption is determined, according to the water-cement ratio
of 0.47 (211.5 mL) AND the fluidity of the mortar reaching 165 mm ~ 175
mm. When the fluidity of the mortar, which is prepared according to the
water-cement ratio of 0.47, exceeds the specified range, the water-
cement ratio shall be increased or decreased, by an integral multiple of
0.01, to make the fluidity reach the specified range. The fluidity of mortar
is determined, according to GB/T 2419-2005, wherein the preparation of
standard sand, lime-sand ratio, mortar is performed according to GB/T
17671-1999.
b) After the test object is formed, place the mold in a curing box, at a
temperature of 20 ??C ?? 1 ??C AND a relative humidity of not less than 90%,
for 6 hours. Then remove the mould. If the mould removal may cause
damage to the test object, the mould removal time can be appropriately
extended, but records shall be kept.
7.4.2 Strength test of self-stressing sulphoaluminate cement
It is carried out according to JC/T 453.
7.5 Alkalinity of low alkalinity sulphoaluminate cements
It is carried out according to the provisions of Appendix B.
7.6 The 28d free expansion rate of low alkalinity sulphoaluminate cement
It is carried out according to JC/T 313-1982 (1996). However, the following
supplements and provisions are made to Chapter 3, Chapter 4, Chapter 5:
a) The temperature of the test chamber shall be kept at 20 ??C ?? 2 ??C, the
relative humidity shall not be less than 50%; the temperature of the
humidity curing box shall be kept at 20 ??C ?? 1 ??C, the relative humidity
shall not be less than 90%; the temperature of the curing water shall be
kept within 20 ??C ?? 1 ??C.
b) It shall make a set of three cement expansion test pieces. The test mortar
consists of: 1000 g of cement, 500 g of medium sand of 0.5 mm ~ 1.0 mm
in the ISO standard sand; the amount of water added shall be based on
the water consumption of the standard cement consistency, which is
determined by GB/T 1346-2001.
c) The mortar is prepared with a JC/T 681 mixer.
d) The test piece, together with mold, is placed in a moisture curing box for
6 hours, before releasing the mold. Measure the initial length. Then place
it in water for curing. The curing age of the specimen is 28 days. The
measurement time is calculated from the time, when the initial length of
the test piece is measured.
7.7 The free expansion rate, self-stress value, 28d self-stress increase rate of
self-stressing sulphoaluminate cement are carried out, according to JC/T 453.
8 Inspection rules
8.1 Exit-factory inspection
Carry out the exit-factory inspection, according to the method specified in
Chapter 7 of this standard. The inspection items include all the technical
requirements of Chapter 6.
8.2 Group-batching and numbering
Sulphoaluminate cement shall be group-batched and numbered, according to
the same variety and grade, before leaving the factory. Bagged cement and
bulk cement shall be group-batched and numbered separately. Each number is
a sampling unit. The exit-factory number of the cement is based on the annual
production capacity of the cement plant. When the daily output exceeds 180 t,
use one number for those not more than 180 t; when it is less than 180 t, use
one number for those not more than the daily output.
The sampling method is carried out according to GB/T 12573. Sampling shall
be representative AND can be taken continuously; or equal samples can be
taken from more than 20 different parts, with a total amount of at least 12 kg.
8.3 Judgment rules
8.3.1 Qualified products
When the exit-factory inspection results meet the technical requirements of
Chapter 6, the exit-factory inspection is judged to be qualified.
8.3.2 Discarded products
8.3.2.1 If any of the alkalinity and 28d free expansion rate, in the low alkalinity
sulphoaluminate cement, does not meet the requirements of this standard, it
shall be judged as a discarded product.
8.3.2.2 When the self-stress value of self-stressing sulphoaluminate cement is
lower than the lowest grade AND the alkali content in the cement does not meet
the requirements of this standard, it shall be judged as a discarded product.
8.3.3 Disqualified product
Within 40 days, if the buyer believes that the product quality does not meet the
requirements of this standard, meanwhile the supplier has objections, both
parties shall send another set of specimen, which is retained by the supplier, to
the national-level cement quality supervision and inspection agency, which is
authorized by the state, for arbitration inspection.
8.5.2.2 When the inspection report of the cement, which has the same number
of the cement manufacturer, is used as the basis for acceptance, the buyer (or
the entrusted supplier) shall take samples from the cement, which has the same
number, before delivery, OR when the product is delivered. The both parties will
sign-seal it AND retain it for 45d.
Within 45d, when the buyer has any doubts about the cement quality, the buyer
and the supplier shall send the jointly sign-sealed specimens to the national-
level cement quality supervision and inspection agency, which is authorized by
the state, for arbitration inspection.
9 Packaging, marking, transportation, storage, use
9.1 Packaging
Sulphoaluminate cement can be packed in bags or in bulk. The net content of
each bag of bagged cement is 50 kg; it shall not be less than 98% of the marked
mass. The total mass of 20 randomly selected bags shall not be less than 1000
kg. Other packaging forms are determined through negotiation, between the
supplier and the buyer; however, the weight requirements for bags shall comply
with the above principles.
Cement packaging bags shall comply with the provisions of GB 9774.
9.2 Marking
The cement bag is clearly marked of the following: product name, code, net
weight, implemented standard number, strength grade, production license
number, manufacturer's name and address, exit-factory number, packaging
date (year, month, day), the words "Strictly prevent moisture". The name and
strength grade of cement shall be clearly marked, on both sides of the
packaging bag AND printed in black.
9.3 Transport and storage
9.3.1 Cement shall not be affected by moisture and mixed with sundries, during
transportation and storage. For the cement, which has different varieties,
strength grades, self-stress grades, it shall be stored and transported
separately AND shall not be mixed.