Concrete Quality Control
Expert-defined terms from the Certificate in Quality Control in Building Construction course at London School of Planning and Management. Free to read, free to share, paired with a professional course.
Admixture – a material added to fresh concrete to modify its properties #
Related terms: plasticizer, set retarder. Example: a superplasticizer increases workability while maintaining low water‑cement ratio. Challenge: ensuring compatibility with cement and aggregates to avoid delayed set.
Alkali‑Aggregate Reaction – a deleterious chemical reaction between alkal… #
Related terms: ASR, expansive cement. Example: cracking in a slab due to ASR can be mitigated by using low‑alkali cement. Challenge: identifying reactive aggregates before construction.
Alkali‑Silica Reaction – the specific form of alkali‑aggregate reaction i… #
Related terms: expansive gel, mitigation. Example: using pozzolanic admixtures reduces alkali availability. Challenge: long‑term monitoring of expansion.
Allowable Tolerance – the permitted deviation from design specifications… #
Related terms: dimensional tolerance, strength tolerance. Example: a 5 % tolerance on compressive strength is common for structural work. Challenge: balancing safety with cost when tolerances are tight.
Aggregate – inert granular material (sand, gravel, crushed stone) that fo… #
Related terms: fine aggregate, coarse aggregate. Example: well‑graded aggregate improves density and reduces voids. Challenge: variability in source material can affect mix consistency.
Air Entrainment – intentional incorporation of microscopic air bubbles to… #
Related terms: air‑void system, air content. Example: 5–7 % entrained air is typical for exterior slabs in cold climates. Challenge: controlling air content without sacrificing strength.
Air‑Void System – the distribution, size, and spacing of air bubbles in e… #
Related terms: air content, freeze‑thaw durability. Example: a proper air‑void system prevents water from accumulating around aggregates. Challenge: accurate measurement using a pressure meter.
Batching – the process of measuring and mixing concrete ingredients in pr… #
Related terms: continuous batching, batch plant. Example: a computer‑controlled batching plant ensures repeatable mixes. Challenge: maintaining accuracy under high production rates.
Batch Plant – a facility where concrete ingredients are weighed, mixed, a… #
Related terms: ready‑mix plant, central mixing. Example: a stationary plant serves multiple construction sites via transit mixers. Challenge: logistics of delivering concrete within its workable time.
Beam Formwork – temporary structures that shape and support concrete beam… #
Related terms: shoring, form release agent. Example: timber or steel forms are used for reinforced concrete beams. Challenge: ensuring alignment and surface finish.
Beton – French term for concrete; used in international standards #
Related terms: Eurocode, EN 206. Example: specifications may reference “beton” in French‑language projects. Challenge: translating terminology for multilingual teams.
Betonstahl – German term for reinforcing steel used in concrete #
Related terms: rebar, Stahlbeton. Example: “Betonstahl” specifications define yield strength and ductility. Challenge: harmonizing standards across borders.
Binder – the component that hardens and binds aggregates, typically cemen… #
Related terms: hydration, pozzolan. Example: fly ash can replace up to 30 % of Portland cement as binder. Challenge: achieving desired early strength when binder content is reduced.
Blended Cement – cement containing a mixture of Portland clinker and supp… #
Related terms: SCM, fly ash. Example: Type II blended cement offers moderate sulfate resistance. Challenge: variability in pozzolan activity affecting setting time.
Bleeding – the upward movement of water to the surface of fresh concrete #
Related terms: settlement, water‑cement ratio. Example: excessive bleeding can weaken the bond between layers. Challenge: controlling mix design to limit bleeding.
Bond Strength – the adhesion capacity between concrete and reinforcing st… #
Related terms: pull‑out test, development length. Example: proper cleaning of rebar improves bond strength. Challenge: corrosion products can reduce bond over time.
Bridge Deck Concrete – concrete used as the riding surface of a bridge #
Related terms: post‑tensioned slab, high‑early‑strength. Example: a high‑early‑strength mix allows traffic to open within 24 hours. Challenge: ensuring durability against de‑icing salts.
Bulk Density – the mass of concrete per unit volume, including voids #
Related terms: specific gravity, porosity. Example: normal‑weight concrete typically has a bulk density of 2,400 kg/m³. Challenge: maintaining target density across batches.
Calcium Aluminate Cement – a cement type rich in C₃A, used for rapid stre… #
Related terms: high‑early‑strength, CA cement. Example: CA cement is employed in precast elements requiring early handling. Challenge: higher heat of hydration can cause cracking.
Calcium Silicate Hydrate – the primary product of cement hydration that g… #
Related terms: C‑S‑H, gel phase. Example: the formation of C‑S‑H creates a dense microstructure. Challenge: controlling moisture to avoid shrinkage.
Calibrated Mixer – a mixer whose speed and capacity are precisely known,… #
Related terms: mixing time, energy input. Example: a calibrated drum mixer reduces variability in slump. Challenge: periodic verification of calibration.
Cambered Beam – a beam with a slight upward curvature to counteract antic… #
Related terms: pre‑camber, deflection control. Example: cambered girders are used in long‑span bridges. Challenge: accurate fabrication of the camber.
Capillary Porosity – the network of small pores that can transport moistu… #
Related terms: drying shrinkage, permeability. Example: low capillary porosity improves durability. Challenge: high water‑cement ratios increase capillary porosity.
Carbonation – the reaction of carbon dioxide with calcium hydroxide, redu… #
Related terms: pH reduction, rebar corrosion. Example: carbonation depth is measured to assess cover performance. Challenge: controlling exposure to CO₂ in humid environments.
Cast‑in‑Place Concrete – concrete poured and cured at the construction si… #
Related terms: in‑situ, formwork. Example: a slab‑on‑grade is a typical cast‑in‑place element. Challenge: ensuring uniform curing conditions across large areas.
Center of Gravity – the point where the weight of a concrete element is e… #
Related terms: structural analysis, balance point. Example: accurate location of the center of gravity is essential for beam design. Challenge: irregular shapes complicate calculation.
Check‑List – a documented list of quality‑control items to verify during… #
Related terms: QC documentation, inspection record. Example: a daily checklist includes slump, temperature, and air content. Challenge: maintaining completeness and traceability.
Chloride Content – the amount of chloride ions present in concrete, influ… #
Related terms: salt exposure, corrosion threshold. Example: chloride ion limit of 0.4 % by weight of cement is common for coastal structures. Challenge: accurately measuring low concentrations.
Clinker – the nodules produced by heating limestone and other raw materia… #
Related terms: kiln, cement production. Example: clinker composition determines cement classification. Challenge: controlling kiln temperature to achieve consistent clinker quality.
Cold‑Weather Concrete – concrete placed at temperatures below 10 °C, requ… #
Related terms: thermal blankets, accelerators. Example: using calcium nitrate accelerates early strength in cold conditions. Challenge: monitoring temperature throughout curing.
Compaction – the process of removing air voids from fresh concrete to inc… #
Related terms: vibration, consolidation. Example: internal vibrators are commonly used for high‑rise construction. Challenge: over‑vibration can cause segregation.
Concrete Curing – the maintenance of moisture, temperature, and time cond… #
Related terms: curing compound, wet curing. Example: curing blankets retain heat for night‑time curing. Challenge: achieving uniform curing in hot or windy climates.
Concrete Durability – the ability of concrete to resist deterioration ove… #
Related terms: freeze‑thaw resistance, chemical attack. Example: a durable mix design incorporates low permeability. Challenge: predicting long‑term performance under variable exposures.
Concrete Mix Design – the systematic procedure for selecting proportions… #
Related terms: ACI 211, target strength. Example: the “w/c ratio” is adjusted to meet strength and workability goals. Challenge: balancing cost, performance, and environmental impact.
Concrete Pump – equipment that transports concrete from the plant to the… #
Related terms: pipeline, pump pressure. Example: a trailer‑mounted pump can deliver concrete up to 30 m vertically. Challenge: avoiding blockages and maintaining slump during pumping.
Concrete Strength – the capacity of hardened concrete to resist compressi… #
Related terms: compressive strength, cylinder test. Example: a 30 MPa specification is typical for residential slabs. Challenge: variability due to curing conditions and mix accuracy.
Control Joint – a deliberately weakened plane that allows concrete to cra… #
Related terms: expansion joint, joint saw. Example: a saw‑cut joint at ¼ depth is placed every 4–5 m in long slabs. Challenge: timing the joint cut to avoid premature cracking.
Coarse Aggregate – granular material retained on a 4 #
75 mm sieve, providing bulk to concrete. Related terms: crushed stone, gravel. Example: a 20 mm maximum size is common for structural concrete. Challenge: ensuring angularity and cleanliness.
Cold‑Weather Additive – admixture used to accelerate setting and strength… #
Related terms: accelerator, heat of hydration. Example: calcium chloride is a common accelerator, though limited by corrosion concerns. Challenge: balancing acceleration with potential for increased shrinkage.
Compaction Factor – a test that measures the degree of compaction achieve… #
Related terms: relative compaction, standard compaction. Example: a factor of 0.95 indicates good vibration efficiency. Challenge: interpreting results for different mix designs.
Concrete Cover – the distance from the outer surface of concrete to the n… #
Related terms: protective cover, corrosion protection. Example: 25 mm cover is typical for interior reinforcement. Challenge: ensuring uniform cover in congested reinforcement zones.
Concrete Pumping Pressure – the hydraulic pressure required to move concr… #
Related terms: pump head, flow rate. Example: a pressure of 80 bar may be needed for a 30 m vertical lift. Challenge: high pressure can cause segregation if mix is not properly designed.
Concrete Temperature – the temperature of fresh or hardened concrete, inf… #
Related terms: thermal monitoring, heat of hydration. Example: measuring temperature at 1 hour after placement helps predict early strength. Challenge: controlling temperature rise in massive pours.
Concrete Workability – the ease with which concrete can be placed, compac… #
Related terms: slump, flow table. Example: a slump of 75 mm is suitable for typical wall construction. Challenge: maintaining workability without excessive water.
Construction Tolerances – permissible deviations in dimensions, location,… #
Related terms: dimensional tolerance, surface tolerance. Example: a 10 mm deviation is allowed for column height. Challenge: ensuring tolerances do not compromise structural integrity.
Control of Segregation – measures taken to prevent the separation of coar… #
Related terms: mix stability, vibration. Example: using a low‑slump, high‑viscosity mix reduces segregation risk. Challenge: balancing workability with stability.
Crack Width – the opening dimension of a concrete crack, used to assess d… #
Related terms: serviceability, fissure. Example: cracks wider than 0.3 mm may permit ingress of deleterious agents. Challenge: controlling shrinkage and thermal stresses to limit crack width.
Crushing Strength – the load at which an aggregate particle fails under c… #
Related terms: aggregate durability, Los Angeles test. Example: a crushing strength of 20 MPa is required for high‑strength concrete. Challenge: sourcing aggregates that meet strength criteria.
Curing Compound – a liquid or membrane applied to the surface to retain m… #
Related terms: evaporation retardant, surface curing. Example: a silicone‑based curing compound forms a thin film that prevents water loss. Challenge: ensuring even application over large areas.
Durability Index – a numerical rating that reflects the resistance of con… #
Related terms: performance class, EN 206. Example: a durability index of “D2” indicates moderate exposure conditions. Challenge: selecting mix components that achieve the target index.
Elastic Modulus – the ratio of stress to strain in the linear portion of… #
Related terms: stiffness, Young’s modulus. Example: an elastic modulus of 30 GPa is typical for normal‑weight concrete. Challenge: variability due to aggregate type and curing.
Expansion Joint – a gap provided to accommodate movement caused by therma… #
Related terms: joint filler, movement accommodation. Example: a pre‑formed neoprene joint filler is used in bridge decks. Challenge: ensuring joint remains sealed to prevent water ingress.
Fine Aggregate – granular material passing a 4 #
75 mm sieve, usually sand. Related terms: sand grading, fineness modulus. Example: well‑graded sand improves workability. Challenge: controlling moisture content, as sand can retain significant water.
Fly Ash – a pozzolanic by‑product of coal combustion, used as a supplemen… #
Related terms: Class F, Class C. Example: Class F fly ash improves long‑term strength and reduces heat of hydration. Challenge: variability in chemical composition between sources.
Formwork – temporary structures that define the shape and support of fres… #
Related terms: shuttering, release agent. Example: steel panel formwork provides a smooth finish for precast walls. Challenge: ensuring alignment and preventing leakage.
Freeze‑Thaw Cycle – the repeated freezing and thawing of concrete in cold… #
Related terms: de‑icing salts, air entrainment. Example: a concrete mix with 6 % entrained air can survive 300 cycles. Challenge: testing to confirm resistance for specific exposure.
Fresh Concrete – concrete in the plastic state, before hardening has begu… #
Related terms: workability, setting time. Example: fresh concrete must be placed within its “window of placement.” Challenge: preventing premature set when temperatures are high.
Full‑Depth Repair – a rehabilitation technique where the entire concrete… #
Related terms: partial repair, remediation. Example: a corroded slab may be demolished and rebuilt to restore structural capacity. Challenge: managing disruption and cost.
Frost Resistance – the ability of concrete to withstand repeated freezing… #
Related terms: air‑void system, durability. Example: specifications often require a minimum of 300 cycles for road pavements. Challenge: verifying resistance through laboratory testing.
Fugitive Dust – fine particles generated during concrete cutting or demol… #
Related terms: dust control, wet cutting. Example: using water‑mist suppression reduces dust emissions. Challenge: complying with occupational safety regulations.
Gage Pressure – the pressure measured by a gauge to monitor concrete pump… #
Related terms: pump pressure, flow rate. Example: a gage pressure of 70 bar indicates the pump is operating within design limits. Challenge: interpreting pressure spikes as possible blockages.
Gypsum – a mineral added to cement to control the rate of setting #
Related terms: set regulator, hemihydrate. Example: excessive gypsum can cause flash set; typical addition is 5 % by weight of clinker. Challenge: maintaining consistent gypsum content across cement batches.
High‑Early‑Strength Concrete – a mix designed to achieve significant stre… #
Related terms: rapid cure, early load. Example: a 30 MPa 1‑day strength allows early traffic opening. Challenge: managing heat of hydration in large volumes.
Hydration – the chemical reaction between cement and water that forms the… #
Related terms: C‑S‑H, heat of hydration. Example: proper hydration is essential for achieving design strength. Challenge: insufficient water or premature drying halts hydration.
Immersion Test – a durability test where concrete specimens are submerged… #
Related terms: chloride penetration, alkali resistance. Example: an immersion test in sodium sulfate solution evaluates sulfate attack resistance. Challenge: correlating laboratory results with field performance.
Inspection Report – a documented record of observations, measurements, an… #
Related terms: QC log, non‑conformance. Example: the report includes slump, temperature, and air content data for each batch. Challenge: ensuring timely completion and signature by responsible parties.
In‑Place Concrete – concrete that is mixed, placed, and cured at the cons… #
Related terms: cast‑in‑place, field curing. Example: a monolithic floor slab is an in‑place element. Challenge: controlling quality under variable site conditions.
Iron Oxide Pigment – a colorant added to concrete to achieve aesthetic fi… #
Related terms: integral color, staining. Example: a 0.5 % addition of red iron oxide yields a brick‑red appearance. Challenge: ensuring uniform distribution without affecting mechanical properties.
Jacking – the process of applying hydraulic force to lift concrete elemen… #
Related terms: post‑tensioning, hydraulic jack. Example: jacking is used to correct settlement of a slab‑on‑grade. Challenge: monitoring stresses to avoid cracking.
Joint Sealant – a flexible material placed in expansion joints to prevent… #
Related terms: joint filler, sealant polymer. Example: a polyurethane sealant remains elastic over a wide temperature range. Challenge: ensuring proper surface preparation for adhesion.
Lag Time – the period between placement and the start of measurable stren… #
Related terms: setting time, early age. Example: a lag time of 2 hours is typical for ordinary Portland cement at 20 °C. Challenge: predicting lag time in cold or hot weather.
Leaching – the dissolution and removal of soluble constituents from concr… #
Related terms: alkali leaching, environmental degradation. Example: high‑alkali cement can leach calcium hydroxide, reducing pH. Challenge: designing mixes to minimize leachable components.
Light‑Weight Aggregate – porous aggregate that reduces concrete density,… #
Related terms: expanded clay, perlite. Example: using 1,200 kg/m³ lightweight aggregate yields a bulk density of 1,800 kg/m³. Challenge: higher water absorption requires careful moisture control.
Load‑Testing – applying controlled loads to concrete elements to verify s… #
Related terms: proof test, structural testing. Example: a load test on a pre‑cast beam confirms design capacity. Challenge: ensuring test setup accurately reflects real conditions.
Long‑Term Strength – the compressive strength attained after 28 days and… #
Related terms: strength gain, maturity. Example: high‑silica fly ash mixes may achieve higher strength at 90 days than ordinary mixes at 28 days. Challenge: specifying appropriate testing intervals.
Low‑Heat Concrete – a mix formulated to limit temperature rise in massive… #
Related terms: heat of hydration, mass concrete. Example: using pozzolans and low‑alkali cement reduces peak temperature by 10 °C. Challenge: achieving required early strength while limiting heat.
Machinery Calibration – verification that weighing, mixing, and pumping e… #
Related terms: scale calibration, meter verification. Example: monthly calibration of the batch weigh scale ensures mix proportion fidelity. Challenge: documenting calibration records for audit.
Moisture Gradient – variation in moisture content through concrete depth,… #
Related terms: drying shrinkage, curing. Example: a steep moisture gradient can cause surface cracking. Challenge: applying curing methods that maintain uniform moisture.
Mortar – a mixture of cement, fine aggregate, and water used for binding… #
Related terms: masonry mortar, grout. Example: a Type S mortar provides high early strength for structural brickwork. Challenge: matching mortar properties to substrate and exposure.
Multiple‑Stage Mixing – a procedure where ingredients are added in succes… #
Related terms: mix sequencing, pre‑mix. Example: adding coarse aggregate first, then cement, then water reduces segregation. Challenge: timing each stage to avoid premature hydration.
Natural Cement – a hydraulic binder produced from limestone that sets wit… #
Related terms: hydraulic lime, historical material. Example: natural cement was used in early 20th‑century structures. Challenge: limited availability and lower strength compared with Portland cement.
Non‑Destructive Testing (NDT) – techniques used to evaluate concrete prop… #
Related terms: ultrasonic pulse velocity, rebound hammer. Example: a rebound hammer provides a quick estimate of surface hardness. Challenge: interpreting results in heterogeneous mixes.
Nominal Mix – a simple proportioning method based on cement, sand, and ag… #
Related terms: empirical mix, standard mix. Example: a 1:2:4 nominal mix yields a moderate strength concrete. Challenge: lack of precise control over water‑cement ratio.
Oblique Joint – a joint cut at an angle, typically used to reduce crackin… #
Related terms: control joint, joint saw. Example: a 45‑degree joint cut can direct cracks away from critical zones. Challenge: ensuring accurate cutting depth and timing.
Permeability – the ability of concrete to allow fluids to pass through it… #
Related terms: water absorption, capillary action. Example: low permeability concrete resists chloride ingress. Challenge: measuring permeability in the field.
Photogrammetry – a surveying technique that uses photographs to create 3‑… #
Related terms: laser scanning, as‑built survey. Example: photogrammetry can detect surface deviations of a poured slab. Challenge: processing large data sets quickly.
Physical Testing – laboratory tests that evaluate concrete properties suc… #
Related terms: mechanical testing, standard specimens. Example: cylinders are cured for 28 days before compression testing. Challenge: maintaining consistent testing conditions.
Plastic Shrinkage – early‑age cracking caused by rapid loss of moisture f… #
Related terms: evaporation, crack formation. Example: high winds and hot temperatures increase risk of plastic shrinkage cracks. Challenge: applying curing compounds promptly.
Portland Cement – the most common hydraulic cement, composed primarily of… #
Related terms: Type I, ASTM C150. Example: Type I Portland cement is suitable for general‑purpose concrete. Challenge: controlling consistency across production batches.
Portland Pozzolana Cement (PPC) – a blended cement containing pozzolanic… #
Related terms: blended cement, SCM. Example: PPC offers better resistance to sulfate attack. Challenge: lower early strength may require admixture adjustments.
Power‑Law Model – a mathematical representation of concrete’s stress‑stra… #
Related terms: constitutive model, non‑linear analysis. Example: the model helps predict ultimate load capacity in finite‑element simulations. Challenge: calibrating model parameters for specific mixes.
Precast Concrete – concrete elements fabricated in a controlled environme… #
Related terms: factory‑produced, modular construction. Example: precast wall panels accelerate construction schedules. Challenge: ensuring proper joint detailing and handling.
Pre‑Stress – the intentional application of compressive stress to concret… #
Related terms: post‑tensioning, pre‑tensioning. Example: pre‑stressed girders reduce deflection under traffic loads. Challenge: maintaining tension over the structure’s life.
Prestressed Concrete – concrete in which steel tendons are tensioned to i… #
Related terms: pre‑stress, tendon. Example: a 30 m span bridge may use pretensioned girders for reduced depth. Challenge: corrosion protection of tendons.
Primary Cement – the main hydraulic binder component in a concrete mix, o… #
Related terms: binder, SCM. Example: the primary cement provides early strength, while supplementary materials enhance durability. Challenge: balancing cost with performance.
Pumpable Concrete – a mix designed to flow through pipelines without segr… #
Related terms: pumpability, flowability. Example: a low‑slump, high‑viscosity mix is ideal for high‑rise pumping. Challenge: avoiding blockage due to aggregate interlock.
Quality Assurance (QA) – systematic activities that ensure processes meet… #
Related terms: quality control, audit. Example: a QA plan outlines procedures for material testing and documentation. Challenge: integrating QA with on‑site construction schedules.
Quality Control (QC) – operational techniques and activities used to fulf… #
Related terms: inspection, testing. Example: QC includes daily slump tests and weekly compressive strength checks. Challenge: real‑time data collection and corrective actions.
Radiant Curing – the use of infrared or microwave energy to accelerate co… #
Related terms: curing accelerator, heat curing. Example: radiant curing can achieve 30 MPa within 4 hours for precast panels. Challenge: uniform heat distribution to avoid thermal gradients.
Rebound Hammer – a portable device that measures surface hardness as an i… #
Related terms: NDT, Schmidt hammer. Example: a rebound number of 35 may correspond to 25 MPa strength. Challenge: calibration for different mix designs.
Reinforcement Corrosion – the deterioration of steel bars due to electroc… #
Related terms: chloride threshold, passivation. Example: corrosion can lead to spalling of concrete cover. Challenge: early detection and protective measures.
Reinforcement Detailing – the arrangement and specification of steel bars… #
Related terms: lap splice, development length. Example: proper bar spacing prevents congestion and ensures concrete flow. Challenge: coordinating with formwork and placement crews.
Relative Humidity – the amount of moisture present in the air relative to… #
Related terms: curing environment, drying shrinkage. Example: maintaining > 60 % relative humidity during curing reduces shrinkage. Challenge: controlling humidity in arid regions.
Repair Mortar – a specialized mortar used to fill cracks, cavities, or su… #
Related terms: patching material, bonding agent. Example: a polymer‑modified repair mortar provides high adhesion. Challenge: achieving compatibility with the existing concrete.
Resin‑Based Sealant – a high‑performance joint filler made from epoxy or… #
Related terms: joint sealant, elastic polymer. Example: a two‑component epoxy sealant offers chemical resistance for industrial floors. Challenge: surface preparation and proper mixing.
Retarder – an admixture that slows the rate of cement hydration, extendin… #
Related terms: set retardation, delayed set. Example: lignosulfonate retarder is used in hot weather to prevent premature stiffening. Challenge: avoiding excessive delay that reduces early strength.
Roller‑Compacted Concrete (RCC) – a zero‑slump concrete placed and compac… #
Related terms: dry‑mix concrete, high‑density paving. Example: RCC dams benefit from rapid placement and high strength. Challenge: achieving uniform compaction without segregation.
Roughness – the texture of a concrete surface, influencing bond with floo… #
Related terms: surface profile, <