Civil Engineering Reference
In-Depth Information
the impregnation of a concrete with polymer transforms the traditional brittle
concrete into a ductile material.
PiC has a wide range of application areas due to its improved durability
and structural properties compared to conventional concrete.
However, its
commercial utilization is restricted for several reasons, the main one being its
complicated technology (naidu, 1992). PiC has been used for the production
of high-strength precast products and to improve the durability of bridge deck
surfaces. Most of the work on partially impregnated concrete has been done
in developing a technique to protect concrete bridge decks and spillways
from damage caused by de-icing salts and freeze-thaw deterioration. The
process has also been applied to concrete stilling basins, curbstones, concrete
pipes and mortar linings, deteriorated buildings and floor constructions.
16.5 Polymer concrete (PC)
16.5.1 Components
PC is a composite material in which the aggregate is bound together in a
polymeric matrix. The composite, therefore, does not contain hydrated cement
phase. Because the use of a polymer instead of Portland cement represents
a substantial increase in cost, PC is employed only in applications in which
the higher cost can be justified by superior properties (Rebeiz, 1996).
in PC, thermosetting resins are generally used as the principal polymeric
component due to their high thermal stability; thermoplastic polymers are
also used to a minor extent. Among the thermosetting, epoxy resins are
mainly employed to produce PC due to the strong adhesion exerted by these
resins to most building materials, their low shrinkage, good creep and fatigue
resistance and low water sorption; however, they are relatively expensive.
Unsaturated polyester resins are also used, due to their superior chemical and
mechanical properties, combined with their lower cost (rebeiz and Fowler,
1996). other materials that are used for PC include: methylmethacrylate,
styrene, vinyl esters, furfuryl alcohol and furan resins, and their copolymers.
Curing agents or initiators are used to promote the curing reactions. For
any PC, the working and curing times depend on the concentration of any
component, the curing temperature, the mass volume.
referring to the aggregates, from a petrological standpoint, limestone,
basalt, silica, quartz, granite, and other high-quality materials are employed,
whether crushed or naturally reduced in size. Aggregates can, however, also
be manufactured from industrial by-products. The use of fly ash as a filler in
polymer concrete is very appealing since it improves the physical properties
of PC, in particular its compressive and flexural strengths (Harja et al., 2009;
Ba˘rbut‚a˘ et al., 2010). The effect of CaCO
3
as a filler on PC was found to
be even more effective than that of fly ash. This was attributed to the larger
