Concrete future - Concrete Mix Design, Quality Control and Specification - page 284

are often based on recent construction practices rather than current ones.
This can be a serious impediment to the promotion and use of innovative
materials and procedures. Although concrete standards are obviously based
on Portland-cement-based concrete, if the materials components are essen-
tially performance-based then innovative alternatives can be considered.
Designers can request independent verification of the use of the product
to help mitigate any possible risks with using a nontraditional concrete.
This has been an excellent system for introducing innovative sustainable
concrete materials in actual structures rather than laboratory specimens to
build confidence in the technology.
National standards and codes which are more prescriptive in nature and
explicitly limit concrete to a Portland-cement-based binder are an impedi-
ment to non-Portland-based binders being accepted in the industry.
13.1.7 Construction practices
Another impediment to the more sustainable use of concrete has been
traditional construction practices that have covered concrete with mar-
ble, tiles, plaster, or paint. There is a different attitude to quality control
of concrete when it is expected to have an off-form finish. We have seen
repetitive defects where the first defect had been cosmetically patched
rather than correcting the placement method that produced the defect.
This has huge cost and sustainability implications. SCC can play an
important role in improving the concrete quality and surface finish as
well as saving contractors significant cost on repairs. The fact that so
many precasters now use SCC is testament to its advantage in reducing
defects and repairs.
Properly constructed concrete using appropriate binder, pigments, and
formwork or grinding can provide an inexpensive, attractive, and durable
finish where the thermal mass of the concrete is directly in contact with the
internal spaces for maximum benefit in terms of thermal attenuation. This
can be augmented by the use of embedded water pipes within the concrete
to efficiently control internal temperatures.
13.1.8 Conclusions
We can produce beautiful, off-form structures with minimal embodied
energy and emissions where most of its components are locally available
throughout the world. Such concrete structures require virtually no main-
tenance. They are fire resistant, flood resistant, and hurricane proof in
the event of severe weather with extremely low energy costs to maintain a
comfortable living environment.
The concrete industry can play a huge role in sustainable development
by eliminating excessive overdesign, rationalising specifications to promote