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According to the requirements of Document JIANBIAO [2014] No.189 issued by the Ministry of Housing and Urban-Rural Development of the People's Republic of China - Notice on Printing and Distributing the ‘Development and Revision Plan on Engineering Construction Standards and Codes in 2015’, the drafting group of standard has revised this standard through the extensive investigation and study, careful summarization of practical experience and reference to relevant international and foreign advanced standards and on the basis of widely soliciting for opinions.
The main technical contents of this standard are: 1. General provisions; 2. Terms and symbols; 3. Basic requirements; 4. Preparation and curing of specimen; 5. Test of compressive strength; 6. Test of axial compressive strength; 7. Test of elastic modulus under static compressive stress; 8. Test of poisson's ratio; 9. Test of splitting tensile strength; 10. Test of flexural tensile strength; 11. Test of axial tensile strength; 12. Test of bond strength between concrete and steel bars; 13. Test of concrete bond strength; 14. Test of abrasion resistance; 15. Test of thermal diffusivity; 16. Test of thermal conductivity; 17. Test of specific heat capacity; 18. Test of linear expansion coefficient; 19. Test of density of hardened concrete; 20. Test of water absorption.
The main contents in the revision of this standard are: 1. The clause “Terms and symbols” is added; 2. The clause “Basic requirements” is added; 3. The preparation and curing of specimen, test of compressive strength, test of axial compressive strength, test of elastic modulus under static compressive stress, test of splitting tensile strength and test of flexural tensile strength of the original standard are revised and improved; 4. The test method for poisson's ratio is added; 5. The test method for axial tensile strength is added; 6. The test method for bond strength between concrete and steel bars is added. 7. The test method for concrete bond strength is added; 8. The test method for abrasion resistance is added; 9. The test method for thermal diffusivity is added; 10. The test method for thermal conductivity is added; 11. The test method for specific heat capacity is added; 12. The test method for linear expansion coefficient is added; 13. The test method for density of hardened concrete is added. 14. The test method for water absorption is added; 15. The “Table of relation between θ/θ0 value and at/D2 value” is added in Annex F.
The Ministry of Housing and Urban-Rural Development of the People's Republic of China is in charge of the administration of this standard, and China Academy of Building Research is responsible for the explanation of specific technical contents. During the process of implementing this standard, the relevant opinions and advices, whenever necessary, can be posted or passed on to Institute of Building Materials of China Academy of Building Research (Address: No.30, North 3rd Ring East Road, Beijing, 100013, China).
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Contents
1 General provisions 1
2 Terms and symbols 2
2.1 Terms 2
2.2 Symbols 3
3 Basic requirements 5
3.1 General requirements 5
3.2 Cross-sectional dimensions of specimen 5
3.3 Dimensional measurement and tolerance of specimen 5
3.4 Test report 6
4 Preparation and curing of specimen 8
4.1 Instrument equipment 8
4.2 Sampling and preparation of specimen 8
4.3 Preparation of specimen 9
4.4 Curing of specimen 11
5 Test of compressive strength 13
6 Test of axial compressive strength 17
7 Test of elastic modulus under static compressive stress 19
8 Test of poisson's ratio 23
9 Test of splitting tensile strength 27
10 Test of flexural tensile strength 31
11 Test of axial tensile strength 35
12 Test of the bond strength between concrete and steel bars 41
13 Test of concrete bond strength 46
14 Test of abrasion resistance 48
14.1 Test of abrasion loss 48
14.2 Test of grinding pit length 51
15 Test of thermal diffusivity 56
16 Test of thermal conductivity 60
17 Test of specific heat capacity 64
18 Test of linear expansion coefficient 67
19 Test of density of hardened concrete 70
20 Test of water absorption 75
Annex A Sample forms of test or inspection report 78
Annex B Preparation of cylinder specimen 87
Annex C Test of compressive strength of cylinder specimen 90
Annex D Test of elastic modulus under static compressive stress of cylinder specimen 92
Annex E Test of splitting tensile strength of cylinder specimen 95
Annex F Table of relation between θ/θ0 value and at/D2 value 98
Explanation of wording in this standard 104
1 General provisions
1.0.1 This standard is formulated with a view to standardizing and unifying the test methods of concrete physical and mechanical properties, and improving the technical level of concrete test.
1.0.2 This standard is applicable to tests of concrete physical and mechanical properties in construction projects. This standard is not applicable to fully-graded concrete and roller-compacted concrete in water conservancy and hydropower projects.
1.0.3 In addition to this standard, the test methods of concrete physical and mechanical properties shall also comply with those stipulated in the current relevant standards of the nation.
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2 Terms and symbols
2.1 Terms
2.1.1 concrete
a kind of engineering material produced by mixing, forming, curing and other processes from the main raw materials such as cement, aggregate and water as well as the mineral admixtures and other admixtures as required according to a certain mix ratio, which has strength after hardening
2.1.2 compressive strength
the maximum pressure a cubic specimen can withstand per unit area
2.1.3 axial compressive strength
the maximum pressure a prismatic specimen can axially withstand per unit area
2.1.4 elastic modulus under static compressive stress
stress required for generation of unit deformation when a prismatic specimen or a cylinder specimen is subjected to a certain axial pressure
2.1.5 poisson's ratio
ratio of the absolute value of the transverse normal strain to that of the axial normal strain of the concrete specimen under axial compression
2.1.6 splitting tensile strength
approximately uniformly distributed ultimate tensile stress generated in the vertical plane under the action of pressure when the middle of the upper and lower surfaces of a cubic specimen or a cylinder specimen is subjected to splitting failure under uniformly distributed pressure
2.1.7 flexural tensile strength
ultimate tensile stress on the surface of concrete specimen when its small beam is subjected to fracture failure under the action of bending moment
2.1.8 axial tensile strength
the maximum tensile force that a concrete specimen can bear per unit area in the axial direction
2.1.9 bond strength
bond stress between new and old concrete materials measured by splitting tensile test
2.1.10 thermal diffusivity
a representation of the rate at which the temperature of each part tends to be consistent when the concrete material is heated or cooled
2.1.11 thermal conductivity
heat flow though concrete material per unit thickness and per unit area under a stable heat transfer state and the action of unit temperature difference
2.1.12 specific heat capacity
heat capacity of unit mass concrete, i.e., the heat absorbed or released by the unit mass concrete at the time of changing the unit temperature
2.1.13 linear expansion coefficient
elongation per unit length of concrete specimen when the concrete temperature rises by 1℃
2.1.14 apparent density
ratio of mass to apparent volume of a dried hardened concrete specimen, with the latter being the sum of the solid volume and the closed pore volume of hardened concrete
2.1.15 as-received density
ratio of mass to total volume of an as-received hardened concrete specimen, with the latter being the sum of solid volume, internal closed pore volume and open pore volume of concrete
2.1.16 water saturated density
ratio of surface dry mass to total volume of a water-saturated hardened concrete specimen, with the latter being the sum of solid volume, internal closed pore volume and open pore volume of concrete
2.1.17 oven-dried density
ratio of mass to total volume of an oven-dried hardened concrete specimen, with the latter being the sum of solid volume, internal closed pore volume and open pore volume of concrete
2.2 Symbols
a——the thermal diffusivity of concrete;
c——the specific heat capacity of concrete;
Ec——the elastic modulus of concrete under static compressive stress;
Et——the elastic tensile modulus of concrete;
fcc——the compressive strength of cubic concrete specimen;
fcp——the axial compressive strength of concrete;
fts——the splitting tensile strength of concrete;
ff——the flexural tensile strength of concrete;
ft——the axial tensile strength of concrete;
fb——the bond strength of concrete;
Gc——the abrasion loss per unit area of concrete;
Wa——the water absorption of concrete;
α——the linear expansion coefficient of concrete;
ρa(bǔ)——the apparent density of hardened concrete;
ρr——the as-received density of hardened concrete;
ρs——the water saturated density of hardened concrete;
ρd——the oven-dried density of hardened concrete;
μ——the poisson's ratio of concrete;
τ——the bond strength between concrete and steel bars;
λ——the thermal conductivity of concrete.
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3 Basic requirements
3.1 General requirements
3.1.1 In the test environment, the relative humidity should not be less than 50%, and the temperature shall be kept at 20℃±5℃.
3.1.2 The test instruments and equipment shall have a certificate of metrological verification or calibration within the validity period.
3.2 Cross-sectional dimensions of specimen
3.2.1 The minimum sectional dimensions of the specimen shall be selected from Table 3.2.1 according to the maximum particle size of aggregates in concrete.
Table 3.2.1 The minimum cross-sectional dimensions of specimens
Maximum particle size of aggregate (mm) Minimum cross-sectional dimensions of specimen
(mm×mm)
Test of splitting tensile strength Other tests
19.0 31.5 100×100
37.5 37.5 150×150
— 63.0 200×200
3.2.2 The specimen shall be prepared by means of the test mold conforming to 4.1.1 herein, and the dimensions of the specimen shall be ensured to meet the requirements.
3.3 Dimensional measurement and tolerance of specimen
3.3.1 The specimen dimensions shall be measured in accordance with the following requirements:
1 The side length and height of the specimen should be measured with vernier caliper, accurate to 0.1mm;
2 The diameter of the cylinder specimen shall be measured with vernier caliper at the two positions perpendicular to each other at the upper, middle and lower parts of the specimen for a total of 6 times, and the arithmetic mean value of the measurements shall be taken as the diameter value, accurate to 0.1mm;
3 The flatness of the bearing surface of specimen may be measured by steel ruler and feeler gauge. During measurement, the steel ruler shall be held vertically with the long side placed horizontally on the bearing surface of specimen, and then be slowly rotated 360°, and its maximum clearance shall be measured with a feeler gauge as the flatness value. Other special equipment may also be used for the flatness measurement. The result shall be accurate to 0.01mm;
4 The included angle between adjacent surfaces of the specimen shall be measured with vernier protractor, accurate to 0.1°.
3.3.2 The dimensional tolerance of each side length, diameter and height of the specimen shall not exceed 1mm.
3.3.3 The flatness tolerance of the bearing surface of specimen shall not exceed 0.0005d, with d being the side length of the specimen.
3.3.4 The included angle between adjacent surfaces of the specimen shall be 90°, with the tolerance not exceeding 0.5°.
3.3.5 The specimen shall be prepared by means of the test mold which meets the standard requirements and is installed accurately, and the dimensional tolerance of the specimen shall be ensured to meet the requirements.
3.4 Test report
3.4.1 The entrusting unit should record the following contents and include them in the test or inspection report:
1 Name of the entrusting unit;
2 Project name and construction position;
3 Name of the inspection item;
4 Other contents needed to be explained.
3.4.2 The specimen fabrication unit should record the following contents and include them in the test or inspection report:
1 Specimen No.;
2 Specimen fabrication date;
3 Concrete strength grade;
4 Shape and dimensions of the specimen;
5 The variety, specification and place of origin of the raw materials and the mix ratio of concrete;
6 Forming method;
7 Curing conditions;
8 Test age;
9 Other contents needed to be explained.
3.4.3 The test or inspection unit should record the following contents and include them in the test or inspection report:
1 Receipt date of the specimen;
2 Shape and dimensions of the specimen;
3 Test No.;
4 Test date;
5 The name, model and number of the instruments and equipment;
6 Laboratory temperature and humidity;
7 Curing conditions and test age;
8 Concrete strength grade;
9 Test results;
10 Other contents needed to be explained.
3.4.4 The sample form of test or inspection report may be in the forms given in Annex A hereto.
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
3.1 General requirements
3.2 Cross-sectional dimensions of specimen
3.3 Dimensional measurement and tolerance of specimen
3.4 Test report
4 Preparation and curing of specimen
4.1 Instrument equipment
4.2 Sampling and preparation of specimen
4.3 Preparation of specimen
4.4 Curing of specimen
5 Test of compressive strength
6 Test of axial compressive strength
7 Test of elastic modulus under static compressive stress
8 Test of poisson's ratio
9 Test of splitting tensile strength
10 Test of flexural tensile strength
11 Test of axial tensile strength
12 Test of the bond strength between concrete and steel bars
13 Test of concrete bond strength
14 Test of abrasion resistance
14.1 Test of abrasion loss
14.2 Test of grinding pit length
15 Test of thermal diffusivity
16 Test of thermal conductivity
17 Test of specific heat capacity
18 Test of linear expansion coefficient
19 Test of density of hardened concrete
20 Test of water absorption
Annex A Sample forms of test or inspection report
Annex B Preparation of cylinder specimen
Annex C Test of compressive strength of cylinder specimen
Annex D Test of elastic modulus under static compressive stress of cylinder specimen
Annex E Test of splitting tensile strength of cylinder specimen
Annex F Table of relation between θ/θ0 value and at/D2 value
Explanation of wording in this standard
