STRCTENG 201 – Introduction to Concrete Engineering

Vocabulary flashcards covering key terms and concepts from the Introduction to Concrete Engineering lecture.

Concrete

A composite material made of coarse aggregates, fine aggregates, Portland cement and water, mixed to meet specific project requirements.

Portland Cement

A hydraulic binder produced by grinding clinker with gypsum; hardens under water to glue aggregates together in concrete.

Aggregate

Inert granular material—sand, gravel or crushed stone—used as filler to give concrete bulk and stability.

Coarse Aggregate

The larger aggregate fraction (typically >4.75 mm) that provides bulk and compressive strength to concrete.

Fine Aggregate

Sand-sized particles (<4.75 mm) that fill voids between coarse aggregate and improve workability.

Water–Cement Ratio (w/c)

Weight of water divided by weight of cementitious materials; key factor controlling strength and durability.

Hydration

Chemical reaction between cement compounds and water that produces solid products and causes concrete to harden.

Calcium Silicate Hydrate (C-S-H)

Primary hydration product that gives hardened cement paste most of its strength.

Pozzolana

Siliceous or siliceous-aluminous material (e.g., volcanic ash) that reacts with lime and water to form cementitious compounds.

Clinker

Hard nodules formed in the kiln at 1400–1600 °C; ground to powder to make Portland cement.

Wet Process

Cement manufacturing method using a slurry of raw materials; high energy demand due to water evaporation.

Dry Process

Energy-efficient cement manufacturing process that grinds and feeds dry powders to the kiln.

Supplementary Cementitious Material (SCM)

Industrial by-products like fly ash or slag added to replace clinker, enhancing sustainability and performance.

Compressive Strength

Concrete’s ability to resist compressive loads, typically 20–70 MPa for normal structural mixes.

Tensile Strength

Concrete’s low resistance to tension, usually about 2–4 MPa.

Modulus of Elasticity

Measure of concrete stiffness; commonly 20–35 GPa for normal-strength mixes.

Workability

Ease with which fresh concrete can be mixed, placed, compacted and finished.

Slump

Field test measuring the vertical settlement of a concrete cone to indicate workability.

Air Entrainment

Intentional inclusion of tiny, stable air bubbles (~5 %) to improve freeze–thaw durability.

Fuller Curve

Ideal gradation curve aimed at maximum aggregate packing density and minimum void content.

Mix Design

Process of selecting concrete component proportions to balance economy, workability and hardened properties.

Saturated Surface-Dry (SSD)

Moisture state where aggregate pores are filled but surfaces are dry, used as reference for water calculations.

Entrained Air

Microscopic, intentionally created air bubbles distributed throughout concrete for durability.

C3S (Tricalcium Silicate)

Main cement compound responsible for early strength gain during hydration.

C2S (Dicalcium Silicate)

Cement phase contributing to long-term strength development.

C3A (Tricalcium Aluminate)

Highly reactive cement compound affecting early heat evolution and sulphate resistance.

C4AF (Tetracalcium Alumino-ferrite)

Cement phase that influences colour and provides minor strength contribution.

Reinforced Concrete

Concrete containing embedded reinforcement (usually steel) to resist tensile stresses.

Rebar

Deformed steel reinforcing bar designed to bond with concrete and carry tensile loads.

Grade 300E Steel

NZ reinforcing steel with 300 MPa yield strength and specified ductility for seismic applications.

Grade 500E Steel

High-strength, earthquake-grade reinforcement with 500 MPa yield strength and high ductility.

Ductility

Ability of a material to undergo significant plastic deformation before failure; essential for seismic performance.

Corrosion

Electrochemical degradation of steel reinforcement inside concrete, leading to expansion and cracking.

Spalling

Breaking off of concrete surface layers, often caused by expansive corrosion products of reinforcing steel.

Cathodic Protection

Technique that applies electrical current or sacrificial anodes to prevent reinforcement corrosion.

Non-metallic Reinforcement

Reinforcing elements that do not corrode, such as fibre-reinforced polymer bars.

Glass Fiber Reinforced Polymer (GFRP)

Composite bar made of glass fibres in a resin matrix; high tensile strength, lightweight and corrosion-free.

Inorganic Polymer Cement (Geopolymer)

Alkali-activated alumino-silicate binder offering up to 85 % lower CO₂ emissions than Portland cement.

Glasscrete

Concrete in which recycled glass replaces part of the aggregate, providing sustainability and aesthetic benefits.

Paintcrete

Concrete incorporating waste paint as an admixture to divert material from landfill.

Thermal Mass

Capacity of concrete to absorb and slowly release heat, improving building energy efficiency.

Fire Resistance of Concrete

Concrete’s ability to retain structural integrity because it neither melts nor burns under fire exposure.

Sulphate-Resistant Cement (SR)

Cement with low C3A content formulated to resist sulphate attack in aggressive soils or waters.

High Early Strength Cement (HE)

Cement designed to gain strength rapidly, useful for fast construction schedules.

Low Heat Cement (LH)

Cement formulated to minimise heat of hydration, reducing thermal cracking in mass pours.

Low Shrinkage Cement (SL)

Cement engineered to limit drying shrinkage and associated cracking.

General Purpose Cement (GP)

Standard Portland cement containing less than 10 % mineral additions.

General Blended Cement (GB)

Cement containing more than 10 % supplementary cementitious materials for sustainability benefits.

Prestressing

Applying compressive stress to concrete before service loads to counteract tensile stresses and limit cracking.

Calcium Carbonate (Limestone)

Primary raw material supplying calcium in cement manufacture; decomposes to lime and CO₂ in the kiln.

Fly Ash

Fine powder by-product from coal combustion, used as an SCM to improve workability and durability.

Environmental Impact of Cement

Cement manufacture contributes ~5 % of global CO₂ emissions through fuel burning and calcination.

Passivation Layer

Protective oxide film formed on steel in alkaline concrete pore solution that inhibits corrosion.

Poisson’s Ratio

Ratio of lateral to longitudinal strain; approximately 0.2 for normal concrete.

Coefficient of Thermal Expansion

Rate of length change with temperature; about 10 × 10⁻⁶ /°C for concrete.