GB/T 27690-2011 English PDF (GBT27690-2011)

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GB/T 27690-2011: Silica fume for cement mortar and concrete
GB/T 27690-2011
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 91.100.10
Q 12
Silica fume for cement mortar and concrete
ISSUED ON. NOVEMBER 21, 2011
IMPLEMENTED ON. AUGUST 01, 2012
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration Committee.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Classification and labels ... 5 
5 Requirements ... 5 
6 Test methods ... 6 
7 Inspection rules ... 7 
8 Packaging, marks, transport and storage ... 8 
Annex A (normative) Inspection method for solid content of silica fume slurry
... 10 
Annex B (normative) Test method for activity index ... 12 
Annex C (normative) Test method for inhibition of alkali aggregate reaction.. 15 
Silica fume for cement mortar and concrete
1 Scope
This Standard specifies the terms and definitions, classification and labels,
requirements, test methods, inspection rules, packaging, marks, transport and
storage of silica fume for cement mortar and concrete.
This Standard is applicable to silica fume for cement mortar 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, Method for Chemical Analysis of Cement
GB/T 2419, Test method for fluidity of cement mortar
GB 6566, Limit for Radionuclides in Building Materials
GB 8076-2008, Concrete Admixtures
GB/T 12573, Sampling method for cement
GB/T 19587, Determination of the specific surface area of solids by gas
absorption using the BET method
GB/T 1767-1999, Method for exterior exposure testes of paint films
GB/T 18736-2002, Mineral admixtures for high strength and high-
performance concrete
GB/T 50082-2009, Standard for test methods of long-term performance and
durability of ordinary concrete
JC/T 420, Method for chemical analysis of chloride for cement raw material
JC/T 681, Mixer for mixing mortars
Radioactivity Ira≤1.0 and Ir≤1.0
Inhibition of alkali aggregate reactivity 14d expansion rate’s reduction value ≥35%
Resistance to chloride ion permeability 28d electric flux ratio ≤40%
NOTE 1. Silica fume slurry is converted into solid content and tested according to this
table.
NOTE 2. The inhibition of alkali aggregate reactivity and chloride ion permeability
resistance is a selective test project, which is determined by both parties.
6 Test methods
6.1 SiO2 content
In accordance with Annex A of GB/T 18736-2002.
6.2 Chlorine content
In accordance with JC/T 420.
6.3 Water content, loss on ignition, total alkali content
In accordance with GB/T 176.
6.4 Solid content
In accordance with Annex A.
6.5 Water demand ratio
In accordance with Annex C of GB/T 18736-2002.
6.6 Specific surface area
In accordance with GB/T 19587.
6.7 Activity index
In accordance with Annex B.
6.8 Radioactivity
In accordance with GB 6566.
6.9 Inhibition of alkali aggregate reactivity
In accordance with Annex C.
6.10 Resistance to chloride ion permeability
Perform according to Clause 7 of GB/T 50082-2009. The resistance to chloride
ion permeation is expressed by the ratio of the tested concrete to the reference
concrete flux. Concrete mix ratio materials shall meet the requirements of GB
8076-2008. The reference concrete mix ratio of cement is 400 kg/m3 ± 5 kg/m3.
Sand rate is 36%~40%. Slump is controlled at 80mm ± 10mm. Incorporate 10%
silica ash into the tested concrete (accounting for the total proportion of
cementitious materials). Use naphthalene-series high-efficiency water-reducing
admixture that meets requirements for standard high-efficiency water-reducing
admixture in GB 8076-2008 to adjust the slump of testing concrete. The water
reducing rate of the water-reducing admixture is required to be greater than
18%.
NOTE. The method for preparing silica fume slurry is carried out according to the method
specified in Annex A.
7 Inspection rules
7.1 Batch number, sampling and sample retention
7.1.1 Batch number
Take 30t of the same type of silica fume/silica fume slurry as an inspection lot.
When it is less than 30t, it shall be regarded as an inspection batch.
7.1.2 Sampling
Sampling is according to GB/T 12573. The sampling shall be representative.
The sampling can be continuous. The same quantity of samples may be taken
from more than 10 different parts. The total shall be at least 5 kg. The silica
fume slurry shall be at least 15 kg. The sample shall be evenly mixed.
7.1.3 Sample retention
The same batch of silica fume samples of manufacturer shall be divided into
two equal portions. One is for product exit-factory inspection. The other is
sealed and stored for 6 months for re-inspection or arbitration.
7.2 Inspection
7.2.1 Exit-factory inspection
The exit-factory inspection items of each batch of silica fume include SiO2
content, water content (solid content), water demand ratio, and loss on ignition.
7.2.2 Type inspection
The type inspection items include all performance indexes in Clause 5 of this
Standard. Type inspection shall be performed in one of the following situations.
a) trial model identification for new product or old product produced in
transferred plant;
b) great changes in material, technique after official production which may
affect product performances;
c) at least once for every-year during normal production;
d) production resumed after log-term discontinued production;
e) great difference between exit-factory inspection results and previous type
inspection results;
f) required by national quality supervision organization.
7.3 Rules for determination
7.3.1 Exit-factory inspection
The inspection results of SiO2 content, water content (solid content), water
demand ratio and loss on ignition shall meet the requirements of Clause 5. If
one of the inspection results does not meet the requirements, it shall be
unqualified product and cannot be delivered.
7.3.2 Type inspection
If all the inspection items comply with the provisions of Clause 5, it shall be
accepted. Should one index fail to meet the requirements of this Standard, it
shall be rejected.
7.4 Re-inspection
During the product storage period, when the user disputes the product quality,
the re-inspection can be performed. Re-inspection can be carried out with the
same number of sealed samples. If the user requests on-site sampling, it shall
be specified in the supply contract in advance. The production plant shall, within
7 days of receiving the user's notice, sample together with the user and send it
to the quality supervision and inspection agency for inspection. If the production
plant shall not go to the site within the specified time, the user may take samples
with the quality inspection agency and the results are equally effective.
8 Packaging, marks, transport and storage
8.1 Packaging
Silica fume can be packed or bulk. Silica fume slurry is packaged in sealed
containers. Environmental considerations shall be considered. The net mass of
Annex A
(normative)
Inspection method for solid content of silica fume slurry
A.1 Method summary
Put a sample of silica fume slurry into a constant wei...