VI. OTHER TYPES OF CONCRETE AND GROUT 



1 . Bituminous Concrete . 



Asphalt is a primary ingredient of all bituminous concretes. It is a 

 natural constituent of many petroleums in which it exists in solution. If 

 the solvent oils are removed by evaporation or distillation from crude 

 petroleum, an asphalt residue remains. Asphalt is a cement, readily 

 adhesive, highly waterproof, and durable. It is a plastic substance and 

 imparts controllable flexibility to mixtures of mineral aggregates with 

 which it is usually combined. 



The three general catagories of bituminous concrete used in coastal 

 structures are: asphalt concrete, a mixture of asphalt cement and both fine 

 and coarse aggregate, placed and compacted to form a monolithic structure; 

 sand asphalt, essentially a type of asphalt concrete with coarse aggregate 

 omitted; and asphalt mastic, basically a sand asphalt having a sufficiently 

 fluid consistency during placement to allow it to flow into voids of a rock 

 structure such as a breakwater or jetty. 



a. Types of Asphaltic Materials . The following terms relating to 

 asphalt are taken from "Asphalt in Hydraulics" (The Asphalt Institute, 1976): 



"(1) Asphalt Cement . Asphalt that is refined to meet specifica- 

 tions for paving, industrial, or special purposes. 



(2) Asphalt Concrete, Hydraulic Type . Similar to asphalt 

 concrete for roadway paving, except, to ensure an essentially void- 

 less mix after compaction, higher mineral filler and asphalt 

 contents are used. 



(3) Asphalt Facing . An asphalt surface designed to resist 

 erosion, abrasion, water pressure, and in some instances, ice 

 pressure. A facing may, in addition, also act as an impermeable 

 layer to prevent leakage through the structure. It may also be 

 termed an asphalt lining or asphalt revetment (see below) . 



(4) Asphalt Grout . A mixture of asphalt, sand, and mineral 

 filler which, when heated and mixed, will flow into place without 

 mechanical manipulation. It is used to bind together a layer of 

 coarse stone of more or less uniform size. It may also be termed 

 asphalt mastic (see below) . 



(5) Asphalt Injection . A pressurized subsurface application 

 of asphaltic material. Usually, injections are made for the 

 purpose of filling subsurface cavities or crevices in the founda- 

 tion soil, or voids beneath an existing pavement layer, primarily 

 for controlling water seepage. 



(6) Asphalt Lining . That part of a hydraulic structure that 

 functions as a durable, erosion-resistant surface. Usually, its 



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