【正文】 ion —Christos PatsatzoglouAbstract：Combining with the specific stipulation in the Regulationfor the Deliveringfor Checking ofthe Witness Sampling in the House Building Projects and Municipal Infrastructure Facilities Projects，the paper illustrates the system for the witness sampling and the delivering for checking，the scopes，the requirements for qualification and the sampling methods for main materials，SO as to direct the practice．Key words：witness sampling，delivering for checking，sampling method，building materials sampling systemWitness sampling system, refers to a person engaged in housing construction and municipal infrastructure works, are required in the construction supervision unit or units designated to witness the clerk witness, used for construction engineering building material, by the construction unit professional materials testing personnel (samplers) on the construction site according to the standard sampling or the making of specimen, and the sample or manufacture specimens sent to meet the requirements of testing laboratory qualification management program2. the scope of witness sampling.The scope of witness sampling for construction engineering project category and structure vary, but to sum up, as long as the main materials used in construction engineering, regardless of the number, how many varieties, are required to witness sampling. Concrete can be divided into three categories:（1） raw materials, used as the works of various cement, sand, stones, steel, machine brick and small block, waterproof materials and so on.（2） semi products, such as various kinds of concrete block masonry mortar test block, reinforced steel bars connecting joints, etc..（3） additive categories, such as various mixed modity concrete additive etc.. requirementsAs the name implies, witness sampling is sampled in a witness member under the witness, witness and the witness in the member will sample sent to laboratory detection, consistent with the requirements so that the witness sampling, involving a total of three acts, namely, the construction side, witness, test, specific parties qualification qualification requirements are as follows:（1） the construction side sampling inspection: must be approved by the professional training and obtain a certificate sampling, authorized by the construction unit responsible for the authorization, field sampling project approaching materials and specimen preparation work, and will try to block, the specimen from the field is transferred to the test unit material and production field sampling of.（2）witness testimony: must be approved by the professional training and obtain a certificate witness, authorized by the construction unit, responsible for the authorization field sampling materials engineering and test block, specimen preparation work in sampling witness, packaging materials and specimen, specimen marking, fill in record account, and representative, the authenticity of the witness sample charge.（3） test laboratory: bear witness sampling inspection tasks must be through the provincial (or above the province) the departments of quality and technology supervision of its measurement (CMA) certification, awarded accreditation and metrology accreditation certificate, but also through the provincial (or above the province) administrative departments of construction of the accreditation, and the issuance of construction engineering quality inspection institution of witness sampling inspection qualification certificate. Testing personnel certificate is needed before detection, and witness identification, seals of the samples examined, witness test reports must be witness signature and seal, and affix the witness dedicated seal test. number of main building materials of witness sampling inspection and sampling methodConstruction project with a variety of materials, but the main material for the safety of the structure of cement, sand, stone, steel, concrete, mortar, masonry materials, simple soil cushion, the sampling quantity, method and mass are summarized as follows. cementThe same manufacturer, the same strength grade, the same species, the same batch and continuous play of bulk cement every 500 t one acceptance batch (less than 500 t in a batch of), sampling method of random never less than three tank, groove shaped pipe in adapting to the position of the insertion depth (cement not more than 2 m). Sampling after mixing evenly out dry sealed container of not less than L2 of kg as the sample in the standard, and take a sample sealing preservation。 bagged cement every 200 t one acceptance batch (less than 200 t in a batch on), randomly from 20 bags to take an equal amount of cement, stirring after 12 kg two, good sealing, a submission, a sealed sample preservation. sandThe same origin, the same specifications for each 400 m3 or 600 t one acceptance batch (less than 400 m3 or 600 t according to a batch of), such as sand quality is relatively stable, slotting amount is large, according to the 1000 t as one acceptance batch. Sampling sampling sites of selected should be uniform, to uproot the sampling position in the surface, 8 copies of each part of the extraction of roughly equal, by mixing 22 kg。 concrete mix ratio test is 100 kg. stonesThe same origin, the same specifications for each 400 m3 or 600 t one acceptance batch (less than 400 m3 or 600 t according to a batch of stones), such as stable quality, slotting amount is large, according to the 1000 t as one acceptance batch. Sampling sampling sites of selected should be uniform, to uproot the sampling position in the surface, 16 copies of each part of the extraction of roughly equal, after classics agitate consisting of a set of samples. Such as stone maximum particle size is 10 mm, 15 mm, 20 mm, take 40 kg。 such as stone maximum particle size is 30 mm, 40 mm, 80 kg。 concrete mix ratio test is 200 kg. steel（1）reinforced materials: th