标准编号:	GB/T 50081-2019
中文名称:	混凝土物理力学性能试验方法标准
英文名称:	Standard for test methods of concrete physical and mechanical properties
行业分类:	GB    国家标准
发布机构:	中华人民共和国住房和城乡建设部 国家市场监督管理总局
发布日期:	2019-06-19
实施日期:	2019-12-1
标准状态:	现行
替代旧标准:	GB/T 50081-2002 普通混凝土力学性能试验方法标准
翻译语言:	英文
文件格式:	PDF
中文字符数:	95000 字
翻译价格(元):	7100.00 元
交付时间:	付款后 1 个工作日

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.



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).

 

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.



 

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——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.



 

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

1 总 则
1.0.1 为规范和统一混凝土物理力学性能试验方法，提高混凝土试验技术水平，制定本标准。
1.0.2 本标准适用于建设工程中混凝土的物理力学性能试验。本标准不适用于水利水电工程中的全级配混凝土和碾压混凝土。
1.0.3 混凝土物理力学性能试验方法除应符合本标准的规定外，尚应符合国家现行有关标准的规定。
2术语和符号
2.1 术 语
2.1.1 混凝土 concrete
以水泥、骨料和水为主要原材料，根据需要加入矿物掺合料和外加剂等材料，按一定配合比，经拌合、成型、养护等工艺制作的、硬化后具有强度的工程材料。
2.1.2抗压强度compressive strength
立方体试件单位面积上所能承受的最大压力。
2.1.3轴心抗压强度axial compressive strength
棱柱体试件轴向单位面积上所能承受的最大压力。
2.1.4 静力受压弹性模量 elastic modulus under static com-pressive stress
棱柱体试件或圆柱体试件轴向承受一定压力时，产生单位变形所需要的应力。
2.1.5 泊松比poisson's ratio
混凝土试件轴向受压时，横向正应变与轴向正应变的绝对值的比值。
2.1.6劈裂抗拉强度splitting tensile strength
立方体试件或圆柱体试件上下表面中间承受均布压力劈裂破坏时，压力作用的竖向平面内产生近似均布的极限拉应力。
2.1.7抗折强度flexural tensile strength
混凝土试件小梁承受弯矩作用折断破坏时，混凝土试件表面所承受的极限拉应力。
2.1.8轴向拉伸强度axial tensile strength
混凝土试件轴向单位面积所能承受的最大拉力。
2.1.9粘结强度bond strength
通过劈裂抗拉试验测定的新老混凝土材料之间的粘结应力。
2.1.10导温系数thermal diffusivity
表征混凝土材料在加热或冷却时，各部分温度趋于一致的速率。
2.1.11 导热系数thermal conductivity
在稳定传热状态和单位温差作用下，通过单位厚度、单位面积混凝土材料的热流量。
2.1.12 比热容 specific heat capacity
单位质量混凝土的热容量，即单位质量混凝土改变单位温度时吸收或放出的热量。
2.1.13线膨胀系数linear expansion coefficient
混凝土温度每升高1℃时，混凝土试件单位长度的伸长量。
2.1.14表观密度apparent density
硬化混凝土烘干试件的质量与表观体积之比，表观体积是硬化混凝土固体体积加闭口孔隙体积。
2.1.15原样体积密度as-received density
硬化混凝土试件在收样原状态下的质量与总体积之比，总体积是混凝土固体体积、内部闭口孔隙体积与开口孔隙体积三者之和。
2.1.16饱水体积密度water saturated density
硬化混凝土饱水试件的表干质量与总体积之比，总体积是混凝土固体体积、内部闭口孔隙体积与开口孔隙体积三者之和。
2.1.17烘干体积密度 oven-dried density
硬化混凝土烘干试件的质量与总体积之比，总体积是混凝土固体体积、内部闭口孔隙体积与开口孔隙体积三者之和。
2.2 符 号
a——混凝土导温系数；
c——混凝土比热容；
Ec——混凝土静力受压弹性模量；
Et——混凝土抗拉弹性模量；
fcc——混凝土立方体试件抗压强度；
fcp——混凝土轴心抗压强度；
fts——混凝土劈裂抗拉强度；
ff——混凝土抗折强度；
ft——混凝土轴向抗拉强度；
fb——混凝土粘结强度；
Gc——混凝土单位面积的磨耗量；
Wa——混凝土吸水率；
α——混凝土线膨胀系数；
ρa——硬化混凝土的表观密度；
ρr——硬化混凝土的原样体积密度；
ρs——硬化混凝土的饱水体积密度；
ρd——硬化混凝土的烘干体积密度；
μ——混凝土泊松比；
τ——混凝土与钢筋的握裹强度；
λ——混凝土导热系数。
3 基本规定
3.1 一般规定
3.1.1 试验环境相对湿度不宜小于50％，温度应保持在20℃±5℃。
3.1.2试验仪器设备应具有有效期内的计量检定或校准证书。
3.2试件的横截面尺寸
3.2.1 试件的最小横截面尺寸应根据混凝土中骨料的最大粒径按表3.2.1选定。
表3.2.1 试件的最小横截面尺寸
骨料最大粒径(mm) 试件最小横截面尺寸
(mm×mm)
劈裂抗拉强度试验 其他试验
19.0 31.5 100×100
37.5 37.5 150×150
— 63.0 200×200

3.2.2 制作试件应采用符合本标准第4.1.1条规定的试模，并应保证试件的尺寸满足要求。
3.3试件的尺寸测量与公差
3.3.1 试件尺寸测量应符合下列规定：
1 试件的边长和高度宜采用游标卡尺进行测量，应精确至0.1 mm；
2 圆柱形试件的直径应采用游标卡尺分别在试件的上部、中部和下部相互垂直的两个位置上共测量6次，取测量的算术平均值作为直径值，应精确至0.1mm；
3 试件承压面的平面度可采用钢板尺和塞尺进行测量。测量时，应将钢板尺立起横放在试件承压面上，慢慢旋转360°，用塞尺测量其最大间隙作为平面度值，也可采用其他专用设备测量，结果应精确至0.01 mm；
4 试件相邻面间的夹角应采用游标量角器进行测量，应精确至0.1°。
3.3.2试件各边长、直径和高的尺寸公差不得超过1mm。
3.3.3 试件承压面的平面度公差不得超过0.0005d，d为试件边长。
3.3.4 试件相邻面间的夹角应为90°，其公差不得超过0.5°。
3.3.5试件制作时应采用符合标准要求的试模并精确安装，应保证试件的尺寸公差满足要求。
3.4试验或检测报告
3.4.1 委托单位宜记录下列内容并写入试验或检测试验报告：
1委托单位名称；
2工程名称及施工部位；
3检测项目名称；
4要说明的其他内容。
3.4.2试件制作单位宜记录下列内容并写入试验或检测报告：
1 试件编号；
2试件制作日期；
3混凝土强度等级；
4试件的形状与尺寸；
5 原材料的品种、规格和产地以及混凝土配合比；
6成型方法；
7 养护条件；
8试验龄期；
9要说明的其他内容。
3.4.3试验或检测单位宜记录下列内容并写入试验或检测报告：
1 试件收到的日期；
2 试件的形状及尺寸；
3 试验编号；
4 试验日期；
5 仪器设备的名称、型号及编号；
6实验室温度和湿度；
7养护条件及试验龄期；
8混凝土强度等级；
9 测试结果；
10要说明的其他内容。
3.4.4 试验或检测报告样表可采用本标准附录A的形式。
4试件的制作和养护
4.1 仪器设备
4.1.1 试模应符合下列规定：
1 试模应符合现行行业标准《混凝土试模》JG 237的有关规定，当混凝土强度等级不低于C60时，宜采用铸铁或铸钢试模成型；
2应定期对试模进行核查，核查周期不宜超过3个月。
4.1.2 振动台应符合现行行业标准《混凝土试验用振动台》JG/T 245的有关规定，振动频率应为50Hz±2Hz，空载时振动台面中心点的垂直振幅应为0.5mm±0.02mm。
4.1.3捣棒应符合现行行业标准《混凝土坍落度仪》JG/T 248的有关规定，直径应为16mm±0.2mm，长度应为600mm±5mm，端部应呈半球形。
4.1.4橡皮锤或木槌的锤头质量宜为0.25kg~0.50kg。
4.1.5对于干硬性混凝土应备置成型套模、压重钢板、压重块或其他加压装置。套模的内轮廓尺寸应与试模内轮廓尺寸相同，高度宜为50mm，不易变形并可固定于试模上；压重钢板边长尺寸或直径应小于试模内轮廓尺寸，两者尺寸之差宜为5mm。
4.2取样与试样的制备
4.2.1 混凝土取样与试样的制备应符合现行国家标准《普通混凝土拌合物性能试验方法标准》GB/T 50080的有关规定。
4.2.2 每组试件所用的拌合物应从同一盘混凝土或同一车混凝土中取样。
4.2.3取样或实验室拌制的混凝土应尽快成型。
4.2.4制备混凝土试样时，应采取劳动防护措施。
4.3试件的制作
4.3.1 试件成型前，应检查试模的尺寸并应符合本标准第4.1.1条中的有关规定；应将试模擦拭干净，在其内壁上均匀地涂刷一薄层矿物油或其他不与混凝土发生反应的隔离剂，试模内壁隔离剂应均匀分布，不应有明显沉积。
4.3.2混凝土拌合物在入模前应保证其匀质性。
4.3.3 宜根据混凝土拌合物的稠度或试验目的确定适宜的成型方法，混凝土应充分密实，避免分层离析。
1 用振动台振实制作试件应按下述方法进行：
1)将混凝土拌合物一次性装入试模，装料时应用抹刀沿试模内壁插捣，并使混凝土拌合物高出试模上口；
2)试模应附着或固定在振动台上，振动时应防止试模在振动台上自由跳动，振动应持续到表面出浆且无明显大气泡溢出为止，不得过振。
2用人工插捣制作试件应按下述方法进行：
1)混凝土拌合物应分两层装入模内，每层的装料厚度应大致相等。
2)插捣应按螺旋方向从边缘向中心均匀进行。在插捣底层混凝土时，捣棒应达到试模底部；插捣上层时，捣棒应贯穿上层后插入下层20mm～30mm；插捣时捣棒应保持垂直，不得倾斜，插捣后应用抹刀沿试模内壁插拔数次。
3)每层插捣次数按10000mm2截面积内不得少于12次。
4)捅捣后应用橡皮锤或木槌轻轻敲击试模四周，直至插捣棒留下的空洞消失为止。
3用插入式振捣棒振实制作试件应按下述方法进行：
1)将混凝土拌合物一次装入试模，装料时应用抹刀沿试模内壁插捣，并使混凝土拌合物高出试模上口；
2)宜用直径为φ25mm的插入式振捣棒；插入试模振捣时，振捣棒距试模底板宜为10mm～20mm且不得触及试模底板，振动应持续到表面出浆且无明显大气泡溢出为止，不得过振；振捣时间宜为20s；振捣棒拔出时应缓慢，拔出后不得留有孔洞。
4 自密实混凝土应分两次将混凝土拌合物装入试模，每层的装料厚度宜相等，中间间隔10s，混凝土应高出试模口，不应使用振动台、人工插捣或振捣棒方法成型。
5 对于干硬性混凝土可按下述方法成型试件：
1)混凝土拌合完成后，应倒在不吸水的底板上，采用四分法取样装入铸铁或铸钢的试模。
2)通过四分法将混合均匀的干硬性混凝土料装入试模约二之一高度，用捣棒进行均匀插捣；捅捣密实后，继续装料之前，试模上方应加上套模，第二次装料应略高于试模顶面，然后进行均匀插捣，混凝土顶面应略高出于试模顶面。
3)插捣应按螺旋方向从边缘向中心均匀进行。在插捣底层混凝土时，捣棒应达到试模底部；捅捣上层时，捣棒应贯穿上层后插入下层10mm~20mm；插捣时捣棒应保持垂直，不得倾斜。每层捅捣完毕后，用平刀沿试模内壁插一遍；
4)每层插捣次数按在10000mm2截面积内不得少于12次；
5)装料插捣完毕后，将试模附着或固定在振动台上，并放置压重钢板和压重块或其他加压装置，应根据混凝土拌合物的稠度调整压重块的质量或加压装置的施加压力；开始振动，振动时间不宜少于混凝土的维勃稠度，且应表面泛浆为止。
4.3.4 试件成型后刮除试模上口多余的混凝土，待混凝土临近初凝时，用抹刀沿着试模口抹平。试件表面与试模边缘的高度差不得超过0.5mm。
4.3.5 制作的试件应有明显和持久的标记，且不破坏试件。
4.3.6 圆柱体试件的制作方法应按本标准附录B执行。
4.4试件的养护
4.4.1 试件的标准养护应符合下列规定：
1 试件成型抹面后应立即用塑料薄膜覆盖表面，或采取其他保持试件表面湿度的方法。
2 试件成型后应在温度为20℃±5℃、相对湿度大于50％的室内静置1 d～2 d，试件静置期间应避免受到振动和冲击，静置后编号标记、拆模，当试件有严重缺陷时，应按废弃处理。
3 试件拆模后应立即放入温度为20℃±2℃，相对湿度为95％以上的标准养护室中养护，或在温度为20℃±2℃的不流动氢氧化钙饱和溶液中养护。标准养护室内的试件应放在支架上，彼此间隔10mm~20mm，试件表面应保持潮湿，但不得用水直接冲淋试件。
4 试件的养护龄期可分为1d、3d、7d、28d、56d或60d、84 d或90d、180d等，也可根据设计龄期或需要进行确定，龄期应从搅拌加水开始计时，养护龄期的允许偏差宜符合表4.4.1的规定。
表4.4.1 养护龄期允许偏差
养护龄期 1d 3d 7d 28d 56d或60d ≥84d
允许偏差 ±30min ±2h ±6h ±20h ±2.4 h ±48h

4.4.2 结构实体混凝土同条件养护试件的拆模时间可与实际构件的拆模时间相同，结构实体混凝土试件同条件养护应符合现行国家标准《混凝土结构工程施工质量验收规范》GB 50204的有关规定。
5抗压强度试验
5.0.1 本方法适用于测定混凝土立方体试件的抗压强度。圆柱体试件的抗压强度试验应按本标准附录C执行。
5.0.2测定混凝土立方体抗压强度试验的试件尺寸和数量应符合下列规定：
1标准试件是边长为150mm的立方体试件；
2边长为100mm和200mm的立方体试件是非标准试件；
3每组试件应为3块。
5.0.3试验仪器设备应符合下列规定。
1 压力试验机应符合下列规定：
1)试件破坏荷载宜大于压力机全量程的20％且宜小于压力机全量程的80％；
2)示值相对误差应为±1％；
3)应具有加荷速度指示装置或加荷速度控制装置，并应能均匀、连续地加荷；
4)试验机上、下承压板的平面度公差不应大于0.04mm；平行度公差不应大于0.05mm；表面硬度不应小于55 HRC；板面应光滑、平整，表面粗糙度Ra不应大于0.80μm；
5)球座应转动灵活；球座宜置于试件顶面，并凸面朝上；
6)其他要求应符合现行国家标准《液压式万能试验机》GB/T 3159和《试验机通用技术要求》GB/T 2611的有关规定。
2 当压力试验机的上、下承压板的平面度、表面硬度和粗糙度不符合本条第1款中第4)项要求时，上、下承压板与试件之间应各垫以钢垫板。钢垫板应符合下列规定：
1)钢垫板的平面尺寸不应小于试件的承压面积，厚度不应小于25mm；
2)钢垫板应机械加工，承压面的平面度、平行度、表面硬度和粗糙度应符合本条第1款要求。
3 混凝土强度不小于60MPa时，试件周围应设防护网罩。
4游标卡尺的量程不应小于200mm，分度值宜为0.02mm。
5 塞尺最小叶片厚度不应大于0.02mm，同时应配置直板尺。
6游标量角器的分度值应为0.1°。
5.0.4立方体抗压强度试验应按下列步骤进行：
1 试件到达试验龄期时，从养护地点取出后，应检查其尺寸及形状，尺寸公差应满足本标准第3.3节的规定，试件取出后应尽快进行试验。
2 试件放置试验机前，应将试件表面与上、下承压板面擦拭干净。
3 以试件成型时的侧面为承压面，应将试件安放在试验机的下压板或垫板上，试件的中心应与试验机下压板中心对准。
4 启动试验机，试件表面与上、下承压板或钢垫板应均匀接触。
5 试验过程中应连续均匀加荷，加荷速度应取0.3MPa/s～1.0MPa/s。当立方体抗压强度小于30MPa时，加荷速度宜取0.3MPa/s~0.5MPa/s；立方体抗压强度为30MPa~60MPa时，加荷速度宜取0.5MPa/s～0.8MPa/s；立方体抗压强度不小于60MPa时，加荷速度宜取0.8MPa/s～1.0MPa/s。
6 手动控制压力机加荷速度时，当试件接近破坏开始急剧变形时，应停止调整试验机油门，直至破坏，并记录破坏荷载。