3.6 Concrete for dams
3.6.1 General
Concrete is a superficially inert but chemically and physically complex
construction material. Its merits lie in adaptability, its use of readily avail-
able mineral resources and, above all, its low bulk cost.
Mass concrete in dams is not subjected to compressive stresses com-
parable with those developed in most other major structures. The volume
of concrete within a dam is relatively great, however, requiring large pours
and high placing rates. Several other properties therefore rank equally
with strength as indices of quality and fitness for purpose. The desirable
characteristics for a mass concrete for use in dams can consequently be
summarized as follows: (a) satisfactory density and strength; (b) durability;
(c) low thermal volume change; (d) resistance to cracking; (e) low perme-
ability; (f ) economy. The listed characteristics are all interrelated to a
greater or lesser degree. As an example, strength, impermeability and
170 CONCRETE DAM ENGINEERING
Fig. 3.21 Alternative monolith construction procedures
