BS PD CEN TS 12390-9-2016 Testing hardened concrete Freeze-thaw resistance with de-icing salts Scaling《硬化混凝土试验 融冰盐抗冻融性 缩放比例》.pdf

1、PD CEN/TS 12390-9:2016 Testing hardened concrete Part 9: Freeze-thaw resistance with de-icing salts Scaling BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06PD CEN/TS 12390-9:2016 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation o

2、f CEN/TS 12390-9:2016. It supersedes DD CEN/TS 12390-9:2006 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee B/516/12, Sampling In Clauses 5, 6 and 7,(for all test methods), a prescription measuring the CO 2 content of the air in the storage room has b

3、een introduced; In Annex A, the alternative applications have been strictly specified; In Annex B, a technical specification has been introduced; In the Bibliography, the references have been updated. EN 12390, Testing hardened concrete, is currently composed with the following parts: Part 1: Shape,

4、 dimensions and other requirements for specimens and moulds; Part 2: Making and curing specimens for strength tests; Part 3: Compressive strength of test specimens; Part 4: Compressive strength Specification for testing machines; Part 5: Flexural strength of test specimens; Part 6: Tensile splitting

5、 strength of test specimens; Part 7: Density of hardened concrete; Part 8: Depth of penetration of water under pressure; Part 9: Freeze-thaw resistance Scaling Complementary element Technical Specification; Part 10: Determination of the relative carbonation resistance of concrete Technical Specifica

6、tion; Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion; Part 13: Determination of secant modulus of elasticity in compression. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announ

7、ce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Roma

8、nia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. PD CEN/TS 12390-9:2016 CEN/TS 12390-9:2016 (E) 4 Introduction Concrete structures exposed to the effects of freezing and thawing need to be durable to have an adequate resistance to this action and, in cases such as

9、road construction, to freezing and thawing in the presence of de-icing agents. It is desirable, especially in the case of new constituents or new concrete compositions, to test for such properties. This also applies to concrete mixes, concrete products, precast concrete, concrete members or concrete

10、 in situ. There are two types of concrete deterioration when a freezethaw attack occurs, scaling and internal structural damage. Test methods on internal structural damage are described in the CEN Technical Report CEN/TR 15177, Testing the freeze-thaw resistance of concrete Internal structural damag

11、e. Many different test methods have been developed. No single test method can completely reproduce the conditions in the field in all individual cases. Nevertheless, any method should at least correlate to the practical situation and give consistent results. Such a test method may not be suitable fo

12、r deciding whether the resistance is adequate in a specific instance but will provide data of the resistance of the concrete to freezethaw-attack and freezethaw-attack in the presence of de-icing agents. If the concrete has inadequate resistance then the freezethaw attack can lead to two different t

13、ypes of damage, namely to scaling (surface weathering) and to internal structural damage. This part of this standard covers only testing for scaling resistance. This Technical Specification has one reference method and two alternative methods. For routine testing either the reference method or one o

14、f the two alternative methods may be used with the agreement of the parties involved. In case of doubt, and if there is no such agreement, the reference method is used. The testing methods may be used for comparative testing or for assessment against fixed acceptance criteria. The application of lim

15、iting values will require the establishment of the correlation between laboratory results and field experience. Due to the nature of the freezethaw action, such correlation would have to be established in accordance with local conditions, reflected in the national application documents. PD CEN/TS 12

16、390-9:2016 CEN/TS 12390-9:2016 (E) 5 1 Scope This Technical Specification describes the testing of the freezethaw scaling resistance of concrete both with water and with sodium chloride solution. It can be used either to compare new constituents or new concrete compositions against a constituent or

17、a concrete composition that is known to give adequate performance in the local environment or to assess the test results against some absolute numerical values based on local experiences. Extrapolation of test results to assess different concretes, i.e. new constituents or new concrete compositions,

18、 requires an expert evaluation. NOTE In some cases the test methods may not be suitable for testing special concretes e.g. high strength concrete or permeable concrete. In these cases the result needs to be treated with caution. Also, the testing methods included in this document may not identify ag

19、gregates that are subject to occasional pop-outs. There is no established correlation between the results obtained by the three test methods. All tests will clearly identify poor and good behaviour, but they differ in their assessment of marginal behaviour. The application of different acceptance li

20、mits for test results enables assessment for different degrees of exposure severity. In case of justified modifications of the test parameters, precautions might apply. Some alternative applications are described in Annex A. 2 Normative references The following documents, in whole or in part, are no

21、rmatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12390-2, Testing hardened concrete - Part 2: Making and

22、curing specimens for strength tests ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 freeze-thaw resistance resistance against alternating freezing and

23、thawing in the presence of water alone 3.2 freeze-thaw resistance with de-icing salt resistance against alternating freezing and thawing in the presence of de-icing salt 3.3 scaling loss of material at the testing surface of concrete due to freeze-thaw attack 3.4 internal structural damage cracks in

24、side concrete which cannot be seen on the surface, but which lead to an alteration of concrete properties, e. g. reduction of the dynamic modulus of elasticity PD CEN/TS 12390-9:2016 CEN/TS 12390-9:2016 (E) 6 4 Making of test specimens Except where details are specified in Clauses 5, 6 and 7 (e.g. t

25、he curing) prepare the test specimens in accordance with EN 12390-2. Concrete that requires vibrating for compaction is compacted on a vibrating table. The pre-storage conditions concerning temperature and moisture are documented. The maximum aggregate size D upper is restricted to one third of the

26、mould length. D upper is the upper permitted value of D for the coarsest fraction of aggregates in the concrete. 5 Slab test (reference method) 5.1 Principle Slab specimens, sawn from concrete test specimens (Figure 1), are subjected to freezethaw attack in presence of a 3 mm deep layer of de-ionize

27、d water or 3 % sodium chloride (NaCl) solution. The freeze thaw resistance is evaluated by the measurement of mass scaled from the testing surface after 56 freezethaw cycles. 5.2 Equipment 5.2.1 Equipment for making 150 mm concrete cubes according to EN 12390-2. 5.2.2 Climate controlled room or cham

28、ber with a temperature of (20 2) C, a relative humidity of (65 5) % and an evaporation rate from a free water surface of (45 15) g/(m 2h) 1) . Normally this evaporation rate is obtained with a wind velocity 0,1 m/s. The evaporation rate is measured from a bowl with a depth of approximately 40 mm and

29、 a cross section area of (225 25) cm 2 . The bowl is filled up with water to (10 1) mm from the brim. The CO 2 content level shall be measured, recorded and kept at a daily average in the range of (300 1 000) ppmv to allow for carbonation 2)5.2.3 Diamond saw for concrete cutting. 5.2.4 Rubber sheet,

30、 (3 0,5) mm thick which is resistant to the salt solution used and elastic down to a temperature of 27 C, or any alternative moisture retaining lining arrangement. 5.2.5 Adhesive for gluing the rubber sheet to the concrete specimen. The adhesive is resistant to the environment in question. NOTE Cont

31、act adhesive has proved to be suitable. 5.2.6 Expanded Polystyrene cellular plastic, (20 1) mm thick with a density of (18 2) kg/m 3or alternative thermal insulation with at least a heat conductivity of 0,036 W/(m K). 5.2.7 Polyethylene sheet, 0,1 mm to 0,2 mm thick. 5.2.8 Freezing medium, consistin

32、g either of 97 % by mass of tap water and 3 % by mass of NaCl (for test with de-icing salt) or of de-ionized water only (for test without de-icing salt). 1) Increased rate of surface evaporation and carbonation influences the microstructure. Different types of concrete will be affected in different

33、ways and to a different extent, having impact on moisture exchange and ranking of the performance. 2) Under ambient (indoor/outdoor) and normal working conditions, adequate CO2 level will automatically be maintained. For smaller, separate rooms or cabinets, the CO2 level may drop significantly, and

34、the level needs to be re-established by introducing fresh air or by other means adding of CO2. PD CEN/TS 12390-9:2016 CEN/TS 12390-9:2016 (E) 7 5.2.9 Freezing chamber with temperature and time controlled refrigerating and heating system with a capacity such that the time-temperature curve presented

35、in Figure 4 can be obtained in specimen, regardless of its position in the chamber. The freezer has a good air circulation. The open-mesh shelves in the freezer are level. No deviation from the horizontal plane shall exceed 3 mm per metre in any direction. 5.2.10 Thermocouples, or an equivalent temp

36、erature measuring device, for measuring the temperature in the freezing medium on the test surface (see Figure 3) with an accuracy within 0,5 K. 5.2.11 Vessel for collecting scaled material. The vessel is suitable for use at temperatures up to 120 C without mass loss and is resistant to attack by so

37、dium chloride. 5.2.12 Suitable paper filter for collecting scaled material, optional. 5.2.13 Synthetic brush, resembling a cloth brush, with semi- soft polyamide (nylon) hairs (see specification in Annex B). 5.2.14 Spray bottle, containing tap water for washing off scaled material. 5.2.15 Drying cab

38、inet, controlled at a temperature of (110 10) C. 5.2.16 Balance, with accuracy within 0,05 g. 5.2.17 Vernier callipers, with accuracy within 0,1 mm. 5.2.18 CO 2 measurement apparatus. 5.3 Preparation of test specimens The test requires four specimens, one from each of four cubes. During the first da

39、y after casting the cubes are stored in the moulds and protected against drying by use of a polyethylene sheet. The air temperature is (20 2) C. After (24 2) h, the cubes are removed from the moulds and placed in a bath with tap water having a temperature of (20 2) C. When the cubes are 7 d old, the

40、y are removed from the water bath and placed in the climate chamber (5.2.2), where they are stored until the freezethaw testing starts. At (21 1) d 3)(50 2) mm thick specimen is sawn from each cube perpendicular to the top surface so that the saw cut for the test surface is located in the centre of

41、the cube, see Figure 1. The variation in thickness within a specimen shall not exceed 2 mm. 3) If for any reason (e.g. difficulties in delivery of samples, ), the cutting date is not strictly 21 d, it is vital to strictly keep the following step for pre-conditioning in the seven days and the re-saturation in the consecutive three days. As a consequence, the final age of the sample may vary accordingly.