The hottest implementation of the new national sta

2022-08-21
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Introduction to the implementation of the new national standard of sand and gravel for construction in China: according to the national standards of the people's Republic of China, the announcement was approved and issued: the two national standards gb/t14684 2001 sand for construction and gb/14685 2001 pebbles and gravel for construction were officially implemented on February 1st, 2002. This national standard replaces the original standards gb/t14685 1993, gb/t

according to the national standards of the people's Republic of China, two national standards, gb/t14684-2001 sand for construction and gb/14685-2001 pebbles and gravel for construction, were officially implemented on February 1, 2002. Tighten it in time; The national standard replaces the original standards gb/t14685-1993 and gb/t14685-1993

in the two newly issued national standards for sand and stone, the original standards have been mainly revised as follows:

1. The classification in the original standard has been cancelled, and it is divided into three categories according to the use of products: class I is suitable for concrete with strength grade greater than C60; Class II is suitable for concrete with strength grade c30-c60 and frost resistance, impermeability or other requirements; Class III should be used for concrete (or building mortar) with strength grade less than C30

therefore, the protection of the oil pump is relatively important in ordinary times

2. The artificial sand is included in the standard universal testing machine. According to different working environments, quasi artificial sand is the general name of machine-made sand and mixed sand after soil removal treatment. Machine made sand is made of rock particles with particle size less than 4.75mm by mechanical crushing and screening, but it does not include particles of soft rock and weathered rock; Mixed sand is made of machine-made sand and natural sand. In order to determine the stone powder content of artificial sand, the methylene basket test method is added to the test method

3. The sand and stone sieving mesh series adopts international standards, which is conducive to the determination of sand and stone particle gradation in line with international standards after China's entry into WTO, and is conducive to the export of sand and stone to surrounding countries and regions

4. In the alkali aggregate reaction test method, the lithofacies method is added to identify the types of rocks and the types of active minerals contained. At the same time, the "rapid alkali silica reaction" method is included in the standard to shorten the test time, which is conducive to the inspection and control of sand and stone quality in the project

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