The Los Angeles abrasion rate of (1) particles with a particle size greater than 1.7mm should not be greater than 30%, and the loss rate of sodium sulfate solution immersion should not be greater than 6%;
(2) The liquid limit of fine particles with a particle size less than 0.5mm should be no more than 25%, and the plasticity index should be less than 6. The construction unit shall sample and test the Los Angeles abrasion rate, sodium sulfate solution immersion loss rate, liquid limit and plasticity index twice in each yard.
2. bed surface graded macadam should meet the design requirements and the following requirements:
(1) Graded macadam material is made of rocks, natural pebbles or gravels through crushing and screening.
(2) The uneven coefficient Cu of graded crushed stone particles is not less than 15, the mass percentage of particles below 0.02mm is not more than 3%, and the mass percentage of surface broken particles in coarse particles above 22.4mm is not less than 30%, and it does not contain impurities such as clay.
During the production of graded macadam, the construction unit shall conduct sampling inspection on the particle size grading 1 time, the content of clay and other impurities, and the content of surface broken particles in coarse particles larger than 22.4 mm..
3. Graded macadam in subgrade transition section shall meet the design requirements and the following requirements:
The particle size, gradation and quality of graded macadam filler in subgrade transition section should meet the design requirements. The content of needle-like and flaky gravel in gravel particles shall not exceed 20%; The content of soft and fragile gravel shall not exceed 10%.
The construction unit shall conduct random inspection per shift 1 time, including particle grading, needle-like and flaky gravel content, soft and brittle gravel content.
Graded macadam shall be tested for maximum dry density before leaving the factory.
Every 5000 m inspection 1 time by the construction unit, when the graded macadam material changes or the quarry is replaced, it should be re-inspected.
Extended data
Classification of graded sand
Natural grading refers to continuous gravel.
The artificial gradation is gravel (20mm-40mm): natural sand: water =9. 1 1:4.97:3.
Graded macadam cushion should be dense and stable, and its particle size grading range should meet the following table:
The above two grayscales are both pad grayscales.
The first rule stipulates that the diameter of all particles should not be greater than 50 mm In order to better meet the compactness, the first rule is recommended!
In addition, in order to prevent frost heaving and wet softness, attention should be paid to controlling the content of fine materials and plasticity index less than 0.5 mm When used as the cushion of asphalt pavement in moderate and wet sections, lime should be added to the gradation, and the fine materials can be appropriately increased. The addition of lime accounts for 8%- 12% of the fine material content. The purpose is to increase the strength and stability of the mat.
Graded macadam is sometimes called graded macadam cushion as cushion, and its particle size is required to be 5-40 mm, of which the content of 25-40 mm is not less than 50%.
reference data
Baidu encyclopedia-graded sand