Civil Engineering Materials: Structural Steel, Cement, Concrete, and Reinforcing Steel

Vocabulary flashcards covering structural steel properties, sections, and specifications; cement chemical compounds, hydration, and types; concrete properties, batching, admixtures, and placement; and reinforcing steel properties and designations.

Elastic Region (Steel)

The initial linear portion of the stress-strain response where small strain occurs proportional to load, described by the Modulus of Elasticity ($E$) through $σ = E ε$.

Yield Stress ($F_y$)

The stress value defining the transition from linear elastic response to the plastic region, where large strain occurs with little or no additional stress.

Tensile Strength ($F_u$)

The peak stress in the strain hardening region of steel; if exceeded, it will cause structural failure and fracture.

Bloom

A semi-finished steel product having a cross-sectional area greater than $36\,\text{in}^2$ ($A > 36\,\text{in}^2$).

Structural Steel Section

A rolled steel member in which at least one cross-sectional dimension is greater than or equal to $3\,\text{inches}$.

Wide Flange (W) Section

The most common structural shape used in buildings, symmetric about both the x-axis and y-axis with flanges of equal size.

H-Pile (HP) Section

A nearly square structural shape with equal web and flange thickness, commonly used as bearing piles.

ASTM A36

All-purpose structural carbon steel containing a maximum of $0.26\%$ carbon and minimum $0.20\%$ copper, with a yield strength of $36\,\text{ksi}$ and ultimate tensile strength of $58\text{--}80\,\text{ksi}$.

ASTM A572

High-strength low-alloy structural steel of structural quality available in Grades 42 to 65 with yield strengths of $42\text{--}65\,\text{ksi}$ and ultimate tensile strength of $60\text{--}80\,\text{ksi}$.

Brittle Fracture

A steel failure mechanism caused by fast loading rates or notches left behind from welding.

Phase Composition of Concrete

The proportion by volume of concrete constituents: $60\%\text{--}75\%$ aggregate (fine and coarse), $25\%\text{--}40\%$ cement paste, and $2\%\text{--}8\%$ voids.

Clinker

The raw nodular product formed in cement production by grinding clay and limestone (calcium) and heating the mixture to $1500\,^{\circ}\text{C}$.

Tricalcium Silicate ($\text{C}_3\text{S}$)

A major compound ($3\text{CaO} \cdot \text{SiO}_2$) accounting for about $60\%$ of Portland cement that hydrates rapidly, producing early strength and early heat of hydration.

Dicalcium Silicate ($\text{C}_2\text{S}$)

A Portland cement compound ($2\text{CaO} \cdot \text{SiO}_2$) accounting for about $16\%$ of cement that hydrates slowly, providing long-term strength gain while giving off the least heat.

Tricalcium Aluminate ($\text{C}_3\text{A}$)

A Portland cement compound ($3\text{CaO} \cdot \text{Al}_2\text{O}_3$) with rapid hydration and high heat release; requires gypsum to retard setting and causes negative sulfate expansion reactions.

Tetracalcium Aluminoferrite ($\text{C}_4\text{AF}$)

A compound ($4\text{CaO} \cdot \text{Al}_2\text{O}_3 \cdot \text{Fe}_2\text{O}_3$) in Portland cement that lowers the clinkering temperature required during manufacturing and reduces the required amount of $\text{C}_3\text{A}$.

Type I Portland Cement

Basic, general-purpose standard Portland cement used in normal construction applications.

Type II Portland Cement

Portland cement providing moderate sulfate resistance and moderate heat rise with low $\text{C}_3\text{A}$ content (~$6\%$).

Type III Portland Cement

Fine-ground Portland cement designed for rapid heat and early strength development, achieving a 1-day strength equal to the typical 3-day strength of Type I.

Type IV Portland Cement

Low-heat Portland cement designed for massive concrete structures to prevent thermal cracking; no longer manufactured in the US due to chemical admixtures.

Type V Portland Cement

High sulfate-resistant Portland cement with reduced $\text{C}_3\text{A}$, suitable for structures exposed to harsh sulfate conditions in water or soil.

Superplasticizer

A chemical admixture/dispersant added to concrete to lower the water-cement ratio or increase slump without adding extra water.

Air Entrainment

An admixture that incorporates microscopic air bubbles into concrete to enhance freeze-thaw resistance and workability.

Pozzolan

A siliceous or siliceous-aluminous material (e.g., fly ash, volcanic ash) that reacts with calcium hydroxide in the presence of water to form cementitious compounds, replacing $15\%\text{--}30\%$ of Portland cement by weight.

Cement Fineness

The specific surface area per unit mass of cement grains (measured in $\text{m}^2/\text{kg}$); higher fineness increases hydration rate and early strength development.

Bleeding (Concrete)

The upward movement of mixing water to the surface of freshly placed concrete due to the settlement of solid particles.

Rebar Numbering System

The standard designation system identifying reinforcing bar size in $1/8\,\text{inch}$ diameter increments (e.g., a #4 bar has a diameter of $4/8\,\text{inch}$ or $1/2\,\text{inch}$).

Carbon Equivalent (CE)

A calculated chemical value indicating steel weldability; rebar requires a CE of $\le 0.55\%$ (max $0.3\%$ carbon, $1.5\%$ manganese) to be weldable.

Welded Wire Fabric

A grid of plain or deformed wires welded at intersections, widely used in slabs and pavements to control shrinkage/temperature cracking.

Slump Test (ASTM C143)

A standard field procedure measuring fresh concrete workability and consistency by assessing the vertical drop of a concrete cone to the nearest $1/4\,\text{inch}$.

Sack Mix

A batching measurement system where 1 sack equals $1\,\text{ft}^3$ ($94\,\text{lbs}$) of cement; a 6-sack mix contains $564\,\text{lb/yd}^3$ of concrete.

Yield (Concrete)

The total volume of concrete in cubic feet produced per single sack of cement.

Consolidation

The process of compacting fresh concrete with mechanical vibrators or tamping rods to eliminate voids and completely fill formwork.

Cold Joint

A plane of structural weakness created when one batch of concrete begins setting before the next batch is placed, preventing homogenous intermixing.

Honeycomb

A rough, open-void defect in hardened concrete caused by insufficient vibration or aggregate segregation during placement.