2. Occurrences and associations of sources
Published:January 01, 2001
This section is intended primarily as an introduction and guide for non-geologists engaged in the aggregates industry. It is intended to be useful in understanding the more straightforward day-to-day geological situations that arise in the development and management of workings. It provides a basis for recognizing the more complex and intractable problems for which specialist geological advice is likely to be needed.
A main contribution of geologists to the study of aggregates is the recognition that rock material owes its properties to its origin, its mineral composition and to the geological processes that have affected it through time. Knowledge of the qualities that determine the suitability of a rock (or concentration of rock fragments) for use as aggregate enables the prospecting geologist to make an informed search for new deposits, recognizing and defining the clear, though not always simple, relationships that exist between the composition, texture, grain-size, fabric and state of weathering of a rock and its likely performance as an aggregate in an engineering structure or other application.
Rock is natural material that forms the crust of the parth. Some rocks are relatively soft, that is to say, weak and easily deformable. Others are hard, strong and durable. Rock so defined includes the ‘soil’ of engineers (that is, all unconsolidated deposits overlying bedrock). However, it does not cover the soils of pedologists (the earthy materials forming the ground in which land plants can grow). Rocks may be examined in cliffs and quarries at the surface and in mines and
Figures & Tables
Aggregates: Sand, gravel and crushed rock aggregates for construction purposes
In 1985, the Geological Society published Aggregates as the first volume in its Engineering Geology Special Publication series. It met with immediate acclaim, being awarded the Brewis Trophy by SAGA in 1986.
“If your work involves the use of aggregates, buy this book and read no further; this volume will be an essential and valuable reference that you will use for many years.” (Canadian Geotechnical Journal 1988)
In 1989, the working party whose work had resulted in the publication of Aggregates was reconvened to revise, update and extend their report. Each chapter was reviewed by independent referees. The second and greatly improved edition, published in 1993 and reprinted in 1998, represented the distillation of a vast body of knowledge and experience held not only by the members of the working party, but also by many international experts, scientists and engineers who contributed as reviewers, referees and corresponding authors.
Owing to continued demand for this unique reference book, a group of aggregate specialists was convened in 1999 in order to review thoroughly and update Aggregates for this third edition.
Outline of contents: Introduction; Occurrences; Field investigations; Extraction; Processing; Classification; Testing; Aggregates for concrete; Aggregates for mortar; Unbound aggregates; Bituminous bound aggregates; Rail ballast; Filter media; Appendix: Aggregate properties; Glossary; Index.
Working Party Members and/or third edition Reviewers: Mr L. Collis (formerly Sandberg); Professor P. G. Fookes (Chairman; consulting engineering geologist), Mr R. A. Fox (formerly RMC Aggregates (UK) Ltd), Professor G. P. Hammersley (formerly Laing Technology Group, now BRE), Mr P. M. Harris (formerly BGS), Dr I. E. Higginbottom (formerly Wimpey Environmental Ltd), Mr J. Lay (RMC Aggregates (UK) Ltd), Dr G. Lees (formerly University of Birmingham), Mr D. I. Roberts (Land and Mineral Resource consultants), Mr A. R. Roeder (formerly British Cement Association), Dr I. Sims (Secretary; formerly Sandberg, now STATS Limited), Dr M. R. Smith (formerly Imperial College, now the Institute of Quarrying), Dr R. G. Thurrell (formerly BGS), Dr G. West (formerly TRL).