Last reviewed 16 Sept 2026 · 9 min read
Classification
| Class | Bonding | General characteristics | Construction examples |
|---|---|---|---|
| Metals | Metallic | Strong, ductile, tough, conductive, often corrode | Structural steel, rebars, aluminium windows, copper pipes |
| Ceramics and glasses | Ionic/covalent | Hard, brittle, strong in compression, heat and chemical resistant | Bricks, tiles, cement, concrete, glass, refractories |
| Polymers | Covalent chains + secondary bonds | Light, corrosion resistant, low stiffness, temperature sensitive | PVC/HDPE pipes, geosynthetics, sealants, insulation |
| Composites | Combination | Tailored properties | RCC, FRP, plywood, fibre-reinforced concrete |
| Advanced/smart materials | Various | Responsive or high-performance | Shape memory alloys, piezoelectrics, self-healing concrete |
Metals
Ferrous metals
| Material | Composition / type | Properties | Uses |
|---|---|---|---|
| Pig iron | Blast furnace product (~3.5–4.5% C) | Brittle; raw material | Steel and cast iron making |
| Cast iron (grey, white, malleable, ductile/SG) | About 2–4% C | Good castability, compressive strength, damping; grey CI brittle; ductile iron tougher | Pipes (ductile iron water mains), manhole covers, machine beds, railings |
| Wrought iron | Very low C with slag fibres | Ductile, corrosion resistant (historic) | Heritage ironwork |
| Mild (low carbon) steel | Up to ~0.25% C | Ductile, weldable, tough | Structural sections, plates, rebars (with microalloying/TMT) |
| Medium/high carbon steels | 0.3–1.5% C | Stronger, harder, less ductile | Rails, wires, springs, tools, prestressing wires (high carbon, cold drawn) |
| High-strength low-alloy (HSLA) steels | Microalloyed (Nb, V, Ti) | Higher strength with weldability | Bridges, heavy structures |
| Weathering steel (e.g. Corten-type) | Cu, Cr, Ni additions | Forms protective rust patina — reduced painting | Bridges, facades |
| Stainless steel | ≥ ~10.5% Cr (+ Ni, Mo) — austenitic (304, 316 — non-magnetic, excellent corrosion resistance), ferritic, martensitic, duplex | Corrosion resistant, aesthetic | Railings, cladding, marine reinforcement, water tanks, fasteners |
| TMT reinforcement bars | Quenched and self-tempered | Hard tempered martensite surface, ductile ferrite–pearlite core | RCC reinforcement (Fe 500, Fe 500D, Fe 550D etc.) |
Non-ferrous metals
| Metal / alloy | Properties | Uses |
|---|---|---|
| Aluminium and alloys | Light (≈ 1/3 density of steel), corrosion resistant (oxide film), good conductor, E ≈ 70 GPa; easily extruded | Windows and doors, curtain walls, roofing sheets, formwork panels, bridges (special), conductors |
| Copper | Excellent electrical/thermal conductivity, ductile, corrosion resistant | Electrical wiring, plumbing pipes, earthing, roofing (heritage) |
| Brass (Cu–Zn), bronze (Cu–Sn) | Corrosion resistant, machinable | Fittings, valves, bearings, statues |
| Zinc | Sacrificial protection of steel | Galvanising, roofing, sacrificial anodes |
| Lead | Dense, soft, corrosion resistant; toxic | Radiation shielding, historic roofing/flashing (use restricted) |
| Titanium | High strength-to-weight, excellent corrosion resistance | Aerospace, marine, some architectural cladding |
| Nickel, chromium | Alloying elements | Stainless steels, plating |
| Tin | Corrosion resistant | Tin plating, solders |
Ceramics
Traditional ceramics
| Material | Features | Uses |
|---|---|---|
| Burnt clay bricks | Fired clay — compressive strength by class, porous | Masonry |
| Tiles (ceramic, vitrified, terracotta) | Hard, wear resistant; vitrified tiles have very low absorption | Flooring, walls, roofing |
| Sanitaryware, stoneware pipes | Glazed, impervious | Toilets, sewers (salt-glazed stoneware) |
| Cement and lime | Hydraulic/non-hydraulic binders | Mortar, concrete, plaster |
| Glass (soda-lime, toughened, laminated, low-e, wired) | Transparent, brittle; toughened glass fractures into small granules; laminated holds fragments | Windows, facades, partitions, skylights |
| Refractories (fireclay, silica, magnesite) | Withstand high temperatures | Kilns, furnaces, chimneys |
| Porcelain insulators | Electrical insulation | Transmission lines |
Advanced ceramics
Alumina (Al₂O₃), silicon carbide (SiC), silicon nitride, zirconia — very hard, wear and heat resistant: cutting tools, abrasives, armour, bearings, sensors.
Polymers
| Class | Examples | Construction uses |
|---|---|---|
| Thermoplastics (remouldable) | PVC, HDPE/LDPE, polypropylene (PP), polystyrene (EPS/XPS), polycarbonate, PMMA (acrylic), nylon, PTFE | Pipes and conduits, window frames, geotextiles/geomembranes, insulation boards, roofing sheets, bearing sliding surfaces |
| Thermosets (cross-linked) | Epoxy, polyester, phenolic, polyurethane (rigid foams), urea- and melamine-formaldehyde | Adhesives, crack injection, coatings, FRP matrices, laminates, insulation |
| Elastomers | Natural rubber, neoprene, EPDM, SBR, silicone | Elastomeric bridge bearings, gaskets, waterproofing membranes, expansion joint seals |
Limitations: low stiffness, creep, UV degradation (without stabilisers), flammability/toxic smoke (some), thermal expansion.