GB/T 18148-2015Earth-moving machinery - Test method for the compaction performance of rollers and compactors (English PDF)

Foreword

This Standard was drafted in accordance with the rules given in GB/T 1.1-2009. This Standard replaces GB/T 18148-2000 Testing method of the compaction performance of rollers and compactors. Compared with GB/T 18148-2000, in addition to editorial modifications, the main technical changes are as follows: - modified the normative references (see Clause 2 of this Edition; Clause 2 of Edition 2000); - modified the definitions of "water content of soil" and "specific gravity of soil" (see 3.1,

3.2 of this Edition; 3.1,

3.2 of Edition 2000); - added the definitions of "theoretical compactness" and "actual compactness" (see 3.7,

3.8 of this Edition); - added the characteristics of test soil; specified the soil plasticity index range (see

4.5 of this Edition); - modified the test content of water content of soil; re-specified the water content division interval and allowable parallel difference (see

4.5.1 of this Edition;

4.5.1 of Edition 2000); - deleted some test equipment and test methods (see 4.5.4.1 ~

4.5.4.5 of Edition 2000); - modified the test content of boundary water content of soil (see

4.5.4 of this Edition;

4.5.4 of Edition 2000); - modified the water content tolerance of test soil (see

5.1.1 of this Edition;

5.1.1 of Edition 2000); - modified the division of prototype work quality range in Table 2 (see

5.1.2 of this Edition;

5.1.2 of Edition 2000); - modified the requirements for compaction speed and the selection of vibration compaction's vibration parameters (see

1 Scope

China's national test method for measuring what a compaction machine actually achieves in the ground. It specifies the testing method for the compaction performance of rollers and compactors, and it applies to vibratory rollers, static wheel rollers, pneumatic tyre rollers, oscillatory rollers, vibrating plate compactors and vibrating impact rammers. Compaction is the cheapest and most consequential operation in earthworks. A road, an embankment, a dam or a foundation fill that is under-compacted settles unevenly after it is finished, and the cost of that shows up years later as cracking and differential settlement that cannot be repaired without rebuilding. Machines are therefore selected on compaction performance - but performance is not a property of the machine alone. It depends on the soil type, on the moisture content relative to optimum, on the lift thickness, on the number of passes and on the travel speed, which is why a manufacturer's claim means nothing without the conditions attached. The method makes the conditions explicit and comparable. A test area of specified soil is prepared and characterised, laid in lifts of stated thickness at a controlled moisture content, and the machine makes a defined number of passes at a defined speed. The resulting density is measured as a function of depth and of pass number, from which the useful compaction depth and the number of passes required to reach a target density are derived. That is what a purchaser needs: not a single figure but the curve, since a heavy machine that compacts deeply may be worse in thin lifts than a lighter one, and a machine needing six passes where another needs three costs twice as much to operate. Issued on 9 October 2015 and in force since 1 June 2016, it replaces GB/T 18148-2000.

This Standard specifies the testing method of the compaction performance of rollers and compactor. This Standard is applicable to compaction performance test of vibratory roller, wheel roller, tire roller, oscillatory roller, vibration plate ram and vibration impact ram.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 50123-1999, Standard for soil test method JTG E40-2007, Test Methods of Soils for Highway Engineering

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

3.1 water content of soil the ratio of the amount of water lost to the constant weight of dry soil at 105°C ~ 108°C, in percentage

3.2 specific gravity of soil the ratio of the mass of the soil to the constant volume at 105°C ~ 108°C and the mass of distilled water at 4°C

3.3 grain composition test of soil a method for determining the percentage of the total mass of the soil in each of the dry granules

3.4 liquid limit of soil the boundary water content of the soil from the plastic state to the flow state

3.5 plastic limit of soil the boundary water content of the soil from the semi-solid state to the plastic state

3.6 compaction test the test of the relationship between the water content and the dry density of the testing material under certain conditions

3.7 theoretical compactness the ratio of the actual dry density after compaction of the soil to the maximum dry density corresponding to the optimum water content of the soil

3.8 actual compactness the ratio of the actual dry density after compaction of the soil to the dry density corresponding to the actual water content of the soil

4 Test equipment

4.1 Information required for testing The standards and various record sheets required for the test.

4.2 Test prototype Before the test, the prototype shall be subjected to trial operation so as to make it in normal working condition.

4.3 Main instruments and appliances The test instruments and appliances must be verified by the national statutory metrological verification organization and shall be used within validity period. If necessary, carry out the calibration and standardization.

4.4 Test site The compaction test site shall be a ground trough with concrete bottom and concrete side (it can be replaced by a fully-compacted soil groove).