Building Design and Construction Handbook - Merritt - Ventech!

CONCRETE CONSTRUCTION 9.5
the owner’s project specifications include a minimum content of cementitious materials,
however, much of the economic incentive for the use of quality control is
lost. See Fig. 9.3 for typical water-cementitious materials ratios.
Note that separate procedures are required for selecting proportions when lightweight
aggregates are used, because their water-absorption properties differ from
those of normal-weight aggregates.
(‘‘Building Code Requirements for Structural Concrete,’’ ACI 318 ‘‘Standard
Specifications for Structural Concrete,’’ ACI 301; ‘‘Standard Practice for Selecting
Proportions for Normal, Heavyweight, and Mass Concrete,’’ ACI 211.1; ‘‘Standard
Practice for Selecting Proportions for Structural Lightweight Concrete,’’ ACI 211.2;
‘‘Recommended Practice for Evaluation of Strength Test Results of Concrete,’’ ACI
214, American Concrete Institute, P.O. Box 9094, Farmington Hills, MI 48333,
‘‘Design and Control of Concrete Mixtures,’’ EB001TC, Portland Cement Association,
5420 Old Orchard Road, Skokie, IL 60077.)
FIGURE 9.3 Curves show variation of 28-day
compressive strength of non-air-entrained concrete
with type of aggregate and watercementitious
materials ratio, except that strengths
exceeding 7000 psi were determined at 56 days.
All mixes contained a water-reducing agent and
100 lb/yd 3 of fly ash. Calculation of watercementitious
materials ratio included two-thirds
of the fly-ash weight in the cement content.