For specimens with the same strength grade and the same curing condition, the number of retained groups shall be determined according to the quantity and importance of concrete, and shall not be less than 5 groups and 2 groups.
Standard curing test block (hereinafter referred to as standard curing test block), same condition curing test block (hereinafter referred to as same condition curing test block), formwork removal test block, impermeability test block, 1, more than 200 cubic meters 1, 000 cubic meters, a group of 200 cubic meters can be used, and * * 6 groups of standard curing test blocks can be used.
In addition, if there is any impermeability requirement, a set of impermeability test blocks shall be set every 500 cubic meters. ***3 groups of impermeability test blocks. Attention should also be paid to the design of several test blocks for formwork removal and maintenance under the same conditions.
Cube test block, also known as cube test block, is used to determine the compressive strength of concrete. In China, the compressive strength of concrete is tested with cubic blocks. Because the volume of 20 cm cube test blocks and test blocks is too large and wastes materials, 15 cm cube test blocks and test blocks are generally used.
The standard curing of general cubic test blocks should be delivered within 28 days, which can be three days in advance and not more than 28 days. Otherwise it will rebound. It is considered that the overage period will be cured above 600 degrees under the same conditions. Generally, the site temperature will accumulate from the day when the concrete is compacted, and it can be delivered when it reaches 600 degrees. The number of days under the same conditions cannot be less than 14 days, nor more than 90 days.
Extended data
In order to unify the inspection and evaluation methods of concrete strength, promote enterprises to improve management level and ensure the quality formulation of concrete strength. Edited by People's Republic of China (PRC) Urban and Rural Construction Environmental Protection Department, approved by People's Republic of China (PRC) State Planning Commission, and released by People's Republic of China (PRC) State Planning Commission on March, 2004 1988+0.
This standard is based on the requirements of Document No.305 of the State Planning Commission [1984], and was compiled by China Institute of Building Research in conjunction with Beijing Construction Engineering Corporation and other 12 units.
In the process of compiling, the related problems of concrete quality and concrete strength inspection and evaluation in China were extensively investigated and systematically tested, and the effective scientific research results were absorbed, and the relevant foreign standards were used for reference. After soliciting the opinions of relevant state units and conducting pilot application, it will be finalized by the national review meeting.
This standard is divided into four chapters and five appendices. The main contents include: general principles, general principles, concrete sampling, specimen making, maintenance and testing, and concrete strength inspection and evaluation.
In the process of implementing this standard, please pay attention to accumulate information and sum up experience. If there is any need to modify or supplement, please send your comments and related materials to the Structural Institute of China Institute of Building Research for reference in future revisions.