The importance of compaction from an historical perspective

Abstract

Paper presented at the 23rd Annual Southern African Transport Conference 12 - 15 July 2004 "Getting recognition for the importance of transport", CSIR International Convention Centre, Pretoria, South Africa. Compaction of soils has been used for as long as mankind had the need to improve the properties of the soil. Properties such as strength and bearing capacity increase with compaction, while the compressibility and permeability reduce. The earliest road builders did not understand the principles of modern day soil mechanics, instinctively they applied mechanical compaction to improve the properties of soils to be used for road construction purposes. In this regard compaction has through history proven to be one of the key processes in road construction. This paper is based on a literature study that was undertaken by the authors for the compilation of course notes for the South African Road Federation. It describes the historical development of compaction for road building purposes, starting with the first known compaction processes by the Mayan around 1500 BC through to modern day compaction techniques. The paper provides background information on the scientific developments that contributed to the understanding of compaction, such as the development of amongst others the CBR, Proctor and Modified AASHTO test. It also highlights the value of properly compacted road materials and how it increases the properties such as strength and bearing capacity.