Polymers and Composites in the Building, Construction, and Civil Engineering Industry

December 2018

The traditional materials for building, construction, and civil engineering applications are wood, inorganic minerals (as in concrete, bricks, stones, and marble), metals, and glass, which have all been used for thousands of years. 

The emergence of synthetic polymers and their composites during the 20th century greatly broadened the range of available materials.  Nowadays, thermoplastic and thermoset polymers and their composites are used increasingly more frequently, in many structures, to perform many functions.

The main reason for this trend is the amazing versatility of polymers, which enables the design and manufacture of a vast range of products to meet very different application requirements at acceptable cost.   

The abilities to prepare blends of polymers, to incorporate many types of performance-enhancing additives, and to prepare polymer matrix composites by incorporating reinforcing agents (such as fibers, platy fillers, and particulate fillers) all enhance the versatility of polymers far beyond the versatility provided by individual polymers on their own.

At Bicerano & Associates, our expertise in polymers and composites helps our clients to develop polymers and composites for any application they may require.

Material Properties

Different properties are of very different relative importance in determining the suitability of a material for a given application.  For example, the properties determining suitability for use as a lead-bearing component such as a column, as an insulating panel placed inside a wall, and as an adhesive, will obviously be quite different.  The properties that have been found to be important for several major types of applications are summarized below.

The stiffness (elastic modulus) and the strength of a construction material are usually its two most important mechanical properties.  It is, for example, impossible to use a material of insufficiently high modulus and strength in many applications where these properties must exceed certain threshold values for the material to perform adequately.  The percent elongation at yield (for materials that manifest a yield point) and the ultimate elongation (the strain at which a material ruptures) are also important in some applications.

Among candidate materials possessing sufficient stiffness and strength, weight reduction often becomes a major secondary selection criterion.  “Specific stiffness” and “specific strength” are defined by the modulus/density and strength/density ratios, respectively.  Polymers have low density so that a given volume of polymer weighs less than the same volume of glass or metal.  Many fiber-reinforced polymers (FRPs), which possess sufficient modulus and strength for a structural application, have higher specific stiffness and specific strength than metals because they have much lower densities, making them preferable for that application.  The superior corrosion resistance of FRPs is often an additional advantage.

Thermal properties are of great importance in some applications.  Polymeric foams which provide exceptional thermal insulation as a result of their very low thermal conductivity and hence are used as thermal insulation materials in buildings provide the best examples.

If a material is being targeted for use as a protective coating, vapor barrier, sealant, or caulking compound, its permeabilities to gases and vapors are important.

If a material is being targeted for use as an adhesive, the strength of the adhesion that it provides and the durability of the adhesion in the application environment are important.

The flammability and burning mechanism of a building material are important.  Many standardized testing methods exist to assess the fire characteristics of building materials.  These characteristics are more important in certain applications than in others.  For example, building codes require polymeric foams used in interior wall insulation to be covered by a thermal barrier or another method to reduce the risk of fire, while there is no such requirement for plastic laminates used for countertops and kitchen cabinets.

If a material is being targeted for use in external construction applications, it is important to determine whether the material will manifest sufficient weathering and aging resistance in the environment to which it will be exposed.  Depending on this environment, the effects of factors such as chemical exposure (such as exposure to acid rain), heat, thermal shock, UV exposure, and exposure to high-energy radiation may need to be considered.

Environmental sustainability is becoming an increasingly important consideration in material selection.  It is, therefore, important to compare the expected environmental impacts of different choices of materials that meet the requirements of an application.

Retrofitting a building with components manufactured from replacement materials is often prohibitively expensive.  Most building materials, therefore, remain for a very long time and in many instances permanently in the buildings that they are parts of.  Hence it is important to keep in mind that some building materials that were once used extensively are either not used at all or used very rarely nowadays due to various reasons for avoiding them that were not initially recognized.  Examples include asbestos, thermal insulation foams manufactured from formaldehyde-containing formulations, and poly(1-butene) pipes.

Finally, cost and profit margins are usually also among the important factors in selecting a material from among candidate materials which all meet the performance requirements.

Examples of Applications

The following industry and application highlights provide a sampling of the vast range of applications of polymers and composites in the building, construction, and civil engineering industry.  Some products that are still in the evaluation stage are also included in these highlights as previews of new technologies and applications that may emerge in the future.

Materials

Applications

Acrylic resins (including variants)

Finishes, caulks, sealants, mastics, safety glazing, binder in paint formulations

Acrylonitrile-butadiene-styrene (ABS) copolymers

Pipes

Concrete-polymer hybrids

Polymer concrete, polymer-impregnated concrete, and sulfur concrete will each be discussed below.

Epoxy resins (including variants such as epoxy acrylate resins and epoxy vinyl ester resins)

The many uses of epoxy resins include:

  • Matrix resins for FRPs.
  • Adhesives, binders, durable protective coatings and overlays, and fillers to patch voids.
  • Binder in paint formulations.
  • Rebar coatings in reinforced concrete.
  • Use instead of Portland cement (the binder used in conventional concrete) to obtain polymer concrete.

Ethylene-vinyl acetate copolymers

Solar panel encapsulants

Fabrics (whether natural or synthetic, all are polymeric)

Wall coverings

Fiber-reinforced concrete (FRC)

FRC is used when reinforcement of concrete may offer performance benefits.  The reinforcing fibers may be selected from among a broad range of options (such as polyamide, polypropylene, polyethylene, steel, glass, basalt, or carbon fibers) depending on the performance needs.

Fiber-reinforced polymers (FRPs)

Thermoset polymers are used more often than thermoplastic polymers in FRPs designed for the construction industry.  Epoxy and polyester thermoset matrices are most commonly used.  Glass, carbon, and aramid fibers are all used in different FRPs.  The many and growing uses of FRPs include:

  • Structural elements in civil engineering structures such as bridges.  Most such applications of FRPs involve the replacement, repair, retrofitting, or reinforcement of a structural component manufactured from a traditional structural material.  The following are some examples:
    • Alternative to steel rebar or complementary to steel rebar for reinforcing concrete.
    • Structural upgrade of steel members.
    • Repair and rehabilitation of reinforced concrete members.
    • Repair and rehabilitation of wood members.
    • Repair and rehabilitation of masonry walls.
  • The many other applications of FRPs include cladding, column wrapping, domes, fencing, masts, pipes, roofing, tanks, and towers.
  • FRPs are still used rarely at present to construct entire civil structures, although the first all-composite bridge superstructure was built in 1982.  Such uses of FRPs are growing and likely to become common over time.
  • FRPs are used rarely at present to construct entire houses, but continuous fiber-reinforced thermoplastic composite panel technology developed around 2010 is gradually gaining acceptance for the rapid and efficient modular construction (through use of composite panels to construct composite walls) of affordable housing. 

Phenolic resins

Adhesives, binders, durable protective coatings and overlays, electrical switch and receptacle covers

Poly(methyl methacrylate) (PMMA)

Transparent and durable thermoplastic polymer (best known by the general public under the Plexiglas tradename) used in sheet form in building windows and other applications as a lightweight and shatter-resistant alternative to glass.  Also used in the surfaces, in sinks, and in pavements of bridge decks.  Cheaper than polycarbonate which provides the better mechanical properties needed in some applications.

Poly(vinyl butyral) (PVB)

Used as the optically clear vibration-stopping inner layer in top-of-the-line laminated glass soundproofing windows

Poly(vinyl chloride) (PVC)

PVC is the polymer that is most widely used in construction applications.  It remains in great demand because of its competitive advantages with respect to flame resistance, safety, frictional behavior, and design versatility.  It is likely to remain the leader in the global construction market over the near future, but probably not indefinitely.

  • PVC is used in windows, doors, facing for buildings, wall coverings, pipes, pipe fittings, ceiling tiles, vinyl flooring (such as floor tiles), electrical wire and cable insulation, and wood plastics composites (as wood replacements that combine wood fibers or flour with polymer).
    • Rigid (unplasticized) PVC is used to replace wood in windows and doors, and also as vinyl siding.
    • Flexible (plasticized) PVC is preferred in wire and cable insulation, and in most PVC pipes.
    • Rigid PVC is preferred in heavy-duty plumbing and draining components.
  • Phthalates used as plasticizers in many flexible PVC formulations and the release of hydrochloric acid (HCl) from all PVC products during a fire raise environmental concerns so that PVC usage may eventually decline.

Polyamides (nylons)

Electrical switch and receptacle covers

Polycarbonate (PC)

Transparent and durable thermoplastic polymer with excellent mechanical properties.  More expensive than PMMA.  Used in dome lights and other lighting fixtures as housings, as flat or curved glazing, as sound walls, and in hot water systems.

Polyesters (including thermoset variants such as alkyd resins and epoxy vinyl ester resins, as well as thermoplastic polyesters)

Floor coating; binder for polymer concrete, paint, fiberglass, and artificial wood; FRP bridge sections; matrix resins for FRPs; adhesives; sealants; polyester fabrics used in roofing and roof maintenance systems; geotextiles used in many civil engineering applications

Polyethylene (PE)

Sheets and other components used in construction, wood plastics, pipes, electrical conduits, foam underlay, coatings, waterproof breathable membranes (such as Tyvek housewrap)

Polyisobutylene

Glazing sealants, waterproof membranes

Polymer concrete

Obtained by using a polymeric resin (such as an epoxy resin, a polyester resin, or an epoxy vinyl ester resin) instead of Portland cement (the binder used in conventional concrete) as the binder.  Used in the same manner as conventional concrete.  The polymeric binder provides the benefit(s) of greater safety and/or durability than conventional concrete, but at a higher cost.

Polymer emulsion (polymer composition not disclosed in product literature)

Terra Dura polymer emulsion is a new agent to bond soil and aggregate particles together at the molecular level to obtain strong and environmentally friendly new cements for use as alternatives to traditional cements.  The Terra Dura polymer is a liquid concentrate that is diluted with water and that cures when the added water evaporates.

Polymer impregnated concrete

Obtained by (1) preparing and hardening conventional concrete by using Portland cement as the binder, (2) impregnating the pore system of the hardened conventional concrete with prepolymers and/or monomers, and (3) allowing the prepolymers and/or monomers to polymerize within the pore system.  Used in the same manner as conventional concrete.  The impregnated polymer improves the strength, durability, chemical resistance, and impermeability of the hardened concrete.  These improvements come at a higher cost since the impregnation of the pores of the hardened conventional concrete with polymer precursors and polymerization of these precursors involve the use of additional materials and process steps.

Polymers used as adhesives

Epoxy adhesives, phenolic adhesives, polyester adhesives, and polyurethane adhesives, used to meet many needs

Polymers used in glass replacement or laminates

PC (glass substitute), PMMA (glass substitute), and PVB (inner layer in top-of-the-line laminated glass windows), used in the applications discussed for each of these polymers

Polymers used in insulation

Foams of polystyrene and of polyurethane (discussed below) are the currently dominant building thermal insulation materials.  There is ongoing research to evaluate textile wastes as alternative building thermal insulation materials as a direction towards attaining greater sustainability.

Polymers used in load-bearing structural elements

FRPs, where many choices are available for the matrix polymer and for the reinforcing fibers, are used in many applications, as summarized above.

Polymers used in piping

ABS, PE, PP, PVC, and FRPs, with miscellaneous applications

Polymers used in wood plastics

Polyethylene (PE), polypropylene (PP), and poly(vinyl chloride) (PVC)

Polypropylene (PP)

Water pipes, waste pipes, wood plastics, sheets used in various construction applications, sound insulation materials, geotextiles used in many civil engineering applications

Polystyrene (PS)

Rigid foam panels for thermal insulation; foam molds for concrete production; foam packaging materials used in the shipment of construction materials

Polyurethane (PU)

Rigid PU foam is widely used for thermal insulation purposes in the building and construction industry.  It is available as foam board, sandwich panels, sprays, aerosol cans, shaped foams, and molded foams.  PU formulations are also used in adhesives, finishes, and carpet underlays.

Silicones

Caulks, sealants

Sulfur concrete (SC)

Unlike conventional concrete which uses Portland cement as binder and which also includes water in its formulation, SC uses sulfur as binder and does not include water in its formulation.  Mixing in the sulfur and heating the mixture causes the molten sulfur to glue together the stones and sand in the formulation.  The product gains its full strength upon cooling.  SC is not used in any major applications yet although it was first developed in the 1970s.  A far-reaching proposal is to use SC (instead of conventional concrete) as a construction material in building colonies on Mars since the Martian soil contains an abundance of sulfur while water is frozen into ice so that liquid water is not readily available.

Waste plastic packaging materials

The use of cleaned and shredded waste plastic packaging materials in bitumen (asphalt) road construction materials is being evaluated in India.

 

Call Bicerano & Associates Consulting, LLC at (912) 235-2238 or use our online form or email us at info@polymerexpert.biz today!

Go to top