• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
Other Concrete Strength Tests - 14071_302
ASPHALTS

Engineering Aid 2 - Intermediate Structural engineering guide book
Page Navigation
  280    281    282    283    284  285  286    287    288    289    290  
Figure 13-27.-Simplified flow chart showing production of road tars from bituminous coals. rod is cast into the concrete to be tested. Then the force required to pull the rod from the concrete is measured. The measured strength is the direct shear strength of the concrete. By correlating the shear strength with the compressive strength, a measurement of the in-place strength is made. BITUMENS AND BITUMINOUS-MATERIALS   TESTING Bituminous pavements are a mixture of well-graded mineral aggregates, mineral filler, and a bituminous cement or binder. They are used as the top portion of a flexible-pavement  structure  to  provide  a  resilient, waterproof, load-distributing medium that protects the base  course  from  detrimental  effects  of  water  and  the abrasive action of traffic. This chapter discusses the materials  used  in  the  construction  of  bituminous surfaces and the methods of identifying and testing these materials. BITUMINOUS-PAVEMENT  MATERIALS Bituminous-pavement  materials  are  made  up  of  a mixture of coarse and fine aggregate, bound together by a liquid or semisolid bituminous binder. The coarse aggregate is stone or gravel that is too large to pass the No. 8 sieve. The fine aggregate is fine gravel and sand, small enough to pass the No. 8 sieve, but too large to pass the No. 200. Fine rock dust that will pass the No. 200 sieve is called mineral dust. A small amount of this may be included in a paving mix, or a small amount of mineral filler may be added to the mix. Commonly used mineral  fillers  are  portland  cement,  pulverized limestone  (called  limestone  dust),  silica  and  hydrated lime. Aggregates Aggregates  may  consist  of  crushed  stone,  crushed or uncrushed gravel, slag, sand, and mineral filler, or a combination of some of these materials. Aggregates normally constitute 90 percent or more, by weight, of bituminous  mixtures,  and  their  properties  have  an important  effect  upon  the  finished  product. Bituminous  Cements Bituminous cement is the adhesive agent in the bituminous mixture and may be either an asphaltic material or a tar. Asphalt may sometimes be obtained from natural deposits but are most generally obtained from the distillation of crude petroleum (fig. 13-26). Tars are obtained from the destructive distillation of bituminous  coal  (fig.  13-27).  The  functions  of 13-35







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.