Many civil engineering projects use soils as fill material, with soil normally being compacted to a dense state to ensure that it has the optimum properties.

Compaction on site is generally achieved by mechanical means such as rolling, ramming or vibrating. Precise control over the level of compaction is essential to achieve best results at reasonable cost, with laboratory compaction tests being used as they provide the basis for control procedures that are subsequently used on site.

This test method utilises a 2.5 kg hand compaction hammer and a one litre capacity compaction mould. Often referred to as the ‘Proctor’ test it is suitable for soils containing particles no larger than 20 mm. The mould and hammer is manufactured from corrosion protected steel components to withstand the heavy usage involved in the test.

Model No. Desc
24-9000 Standard compaction mould
24-9002 Standard compaction rammer

This test method utilises a 4.5 kg hand rammer resulting in a heavier compactive effort than the 2.5 kg test method. Compactive energy some 4.5 times greater is applied to the sample using the heavier rammer.

The method is often specified where higher levels of compaction are necessary in a structure, e.g. an airfield sub-base material. Manufactured from corrosion protected steel components the 4.5 kg rammer is designed to withstand heavy usage involved in the test method.

Model No. Desc
24-9010 300 mm straight edge
24-9004 4.5 kg compaction rammer

The time and effort required to prepare specimens for compaction studies and other test methods can often be costly and time-consuming. The use of an automatic, mechanical compactor will show considerable cost benefits over hand compaction methods. Two models meeting the requirements of BS/EN and ASTM are available.

• Pre-set blow pattern ensures even compaction
• Solid state controls for reliability and ease of maintenance
• Automatic re-setting of counter after completion of blow pattern

These machines automatically compact specimens eliminating the laborious hand compaction method. The height of the rammer is selectable to suit test requirements. The weight of the rammer is selectable. An automatic blow pattern ensures optimum compaction for each layer of soil. The rammer travels across the mould and the table rotates the mould in equal steps on a base that is extremely stable. The number of blows per layer can be set at the beginning of the test.

Model No. Voltage Desc BS/EN ASTM/AASHTO

The California Bearing Ratio test, or CBR test as it is usually termed, is an empirical test first developed in California, USA, for estimating the bearing value of highway sub-bases and sub-grades. The test follows a standardised procedure and there is little difference between BS/EN and ASTM tests. However, there are numerous ways of preparing samples and in this respect American practice differs in detail from British practice.

A range of load rings will be required depending upon the type of material being tested. Detailed below is a selected range of load rings and transducers that are suitable for differing values of CBR.

Model No. Desc CBR %
27-1559 S-type load cell - 50 kN ALL
78-0060 Load ring - 2 kN Up to 8%
78-0460 Load ring - 10 kN 8% to 40%
78-0760 Load ring - 28 kN Average range of CBR
78-0860 Clamped Boss Load ring - 50 kN Above 40%

A range of moulds and accessories designed to meet relevant Standards. The equipment is manufactured from high quality materials and with regular maintenance will give years of satisfactory performance.

Model No. Desc
24-9198 CBR mould body

The use of in-situ CBR apparatus on road construction contracts enables the bearing capacity of soils to be determined quickly and efficiently with minimum delay. The BS 1377, BS 1924 and ASTM D4429 standards describe in-situ test procedures.