Proctor Test ASTM D1557-12

Laboratory Compaction of Soil Using Modified

Test Method

A soil at a selected molding water content is placed in five layers into a mold of given dimensions, with each layer compacted by 25 or 56 blows of a 10.00-lbf (44.48-N) rammer dropped from a distance of 18.00 in. (457.2 mm), subjecting the soil to a total compactive effort of about 56 000 ft-lbf/ft3 (2700 kn-m/m3). The resulting dry unit weight is determined. The procedure is repeated for a sufficient number of molding water contents to establish a relationship between the dry unit weight and the molding water content for the soil. This data, when plotted, represent a curvilinear relationship known as the compaction curve. The values of optimum water content and modified maximum dry unit weight are determined from the compaction curve.

Significance and Use

Laboratory compaction tests provide the basis for determining the percent compaction and molding water content needed to achieve the required engineering properties, and for controlling construction to assure that the required compaction and water contents are achieved.

 Proctor Graph 

Apparatus for Proctor Test

Nasir Abbasi
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