Capital Equipment News February 2015

COMPACTION

INTRODUCTION TO COMPACTION

The process of construction relies heavily on the compaction of the soil before any building operation can commence. Soil compaction is used for the support of struc- tural entities such as building foundations, roadways, walkways and earth retaining structures, to name a few. For a given soil type certain properties may deem it more or less desirable to perform adequately for a particular circumstance. In general, the preselected soil should have adequate strength, be relatively incompressible so that future settlement is not significant, be stable against volume change as wa- ter content or other factors may vary, be durable and safe against deterioration and possess proper permeability. To ensure adequate soil compaction is achieved, project specifications will indi- cate the required soil density or degree of compaction that must be achieved. The composition of the soil has a great influ- ence on the maximum dry unit weight and optimum moisture content. It also has a

great influence on how the materials should be compacted in given situations.

Compaction is accomplished by use of heavy equipment. In sands and gravels vi- bratory type equipment is used. This caus- es re-orientation of the soil particles into a denser configuration. In silts and clays, a pad foot roller is frequently used to cre- ate small zones of intense shearing which drives air out of the soil. When selecting equipment for compaction it is therefore essential to choose the most effective type of machine for the job which is determined by the soil type. There are various types of equipment available such as, the Rammer which gives high impact forces, the Forward Plate Compactor de- signed for mainly granular soils and Roll- ers of various sizes and weights that are normally employed in road construction soil compression. Some of the most com- mon types are the walk-behind and ride- on rollers. b

“The composition of the soil has a great influence on the maximum dry unit weight and optimum moisture content. It also has a great influence on how the materials should be compacted in given situations.”

CAPITAL EQUIPMENT NEWS FEBRUARY 2015 6