Building Materials and Concrete Technology MCQs 2026

Ordinary Portland Cement (OPC) is manufactured by grinding clinker with a small amount of

1. A sand ✓
2. B lime only ✓
3. C fly ash only ✓
4. D gypsum ✓

The compound C3S in Portland cement clinker is primarily responsible for

1. A early strength development ✓
2. B sulphate resistance only ✓
3. C long-term heat of hydration only ✓
4. D air entrainment ✓

C2S in cement contributes mainly to

1. A immediate flash set ✓
2. B later-age strength gain ✓
3. C high early heat only ✓
4. D efflorescence ✓

C3A reacts rapidly with water and is controlled by adding

1. A extra sand ✓
2. B only water reducers ✓
3. C gypsum during grinding ✓
4. D coarse aggregate ✓

Fineness of cement is commonly measured by

1. A Blaine air permeability test ✓
2. B slump test ✓
3. C aggregate impact value ✓
4. D Proctor test ✓

Initial setting time of OPC should not be less than

1. A 10 minutes ✓
2. B 30 minutes ✓
3. C 60 minutes ✓
4. D 12 hours ✓

Final setting time of OPC should not exceed

1. A 60 minutes ✓
2. B 600 minutes (10 hours) ✓
3. C 30 minutes ✓
4. D 24 hours always ✓

Hydration of cement is

1. A a chemical reaction between cement and water forming C-S-H gel ✓
2. B only physical drying ✓
3. C evaporation of mixing water only ✓
4. D carbonation only ✓

Heat of hydration is highest for cement rich in

1. A C3A and C3S ✓
2. B C2S only ✓
3. C gypsum only ✓
4. D inert fillers ✓

Rapid Hardening Cement attains high early strength because it is

1. A coarser than OPC ✓
2. B free of gypsum ✓
3. C pure lime ✓
4. D finer ground with higher C3S content ✓

Sulphate Resistant Cement has low

1. A C2S content ✓
2. B gypsum ✓
3. C silica fume ✓
4. D C3A content ✓

Portland Pozzolana Cement uses pozzolana to improve

1. A only colour ✓
2. B workability, durability and resistance to chemical attack ✓
3. C only aggregate grading ✓
4. D zero strength ✓

White cement is produced using

1. A high fly ash only ✓
2. B sea water curing only ✓
3. C iron-free or low-iron raw materials and cooler kiln conditions ✓
4. D extra C3A ✓

Water-cement ratio primarily governs

1. A strength and durability of hardened concrete ✓
2. B only slump ✓
3. C only aggregate shape ✓
4. D formwork cost only ✓

According to Abrams law, concrete strength is inversely related to

1. A cement content alone ✓
2. B aggregate size only ✓
3. C air temperature only ✓
4. D water-cement ratio ✓

Workability of fresh concrete is commonly assessed by

1. A compressive test on hardened cubes ✓
2. B Rebound hammer ✓
3. C slump test ✓
4. D core cutting ✓

A true slump indicates

1. A shear failure of cone ✓
2. B concrete subsides uniformly without disintegration ✓
3. C collapse slump ✓
4. D zero movement ✓

Segregation in concrete means

1. A uniform distribution ✓
2. B air entrainment ✓
3. C proper curing ✓
4. D separation of coarse aggregate from mortar ✓

Bleeding in fresh concrete is

1. A rise of free water to the surface ✓
2. B loss of cement ✓
3. C air loss only ✓
4. D instant setting ✓

Bulking of sand occurs due to

1. A surface moisture films increasing apparent volume ✓
2. B cement hydration ✓
3. C aggregate crushing ✓
4. D chemical reaction with cement ✓

Fineness Modulus of sand indicates

1. A cement strength ✓
2. B slump in mm only ✓
3. C water demand zero ✓
4. D average particle size — higher FM means coarser sand ✓

Coarse aggregate for RCC should generally be

1. A soft shale only ✓
2. B organic clay lumps ✓
3. C well graded, clean, hard and durable ✓
4. D highly absorptive without limit ✓

Maximum size of coarse aggregate is often limited by

1. A colour of formwork ✓
2. B spacing of reinforcement and cover thickness ✓
3. C type of cement only ✓
4. D wind speed ✓

Grading of aggregate means

1. A particle size distribution across standard sieves ✓
2. B shape only ✓
3. C specific gravity only ✓
4. D moisture only ✓

Specific gravity of aggregates is used to

1. A measure slump ✓
2. B convert mass batching to volume batching and mix design ✓
3. C test compressive strength ✓
4. D determine setting time ✓

Water absorption of aggregate affects

1. A effective water-cement ratio in mix ✓
2. B only colour ✓
3. C only formwork pressure ✓
4. D gypsum content ✓

Deleterious materials in aggregate include

1. A clean crushed granite only ✓
2. B well-graded quartz ✓
3. C SSD moisture ✓
4. D clay lumps, organic impurities and excessive fines ✓

Alkali-aggregate reaction (AAR) involves

1. A only sulphate in soil ✓
2. B only carbonation ✓
3. C reactive silica in aggregate with alkaline cement pore solution ✓
4. D only chloride attack ✓

Air entrainment in concrete is achieved using

1. A extra cement only ✓
2. B coarse sand only ✓
3. C high w/c only ✓
4. D air-entraining admixtures (e.g., Vinsol resins) ✓

Water-reducing admixtures (plasticizers) allow

1. A higher w/c always ✓
2. B no cement ✓
3. C instant set only ✓
4. D lower water content for same workability ✓

Retarding admixtures are used to

1. A delay setting time in hot weather or long haul ✓
2. B accelerate strength always ✓
3. C increase bleeding only ✓
4. D replace cement ✓

Accelerating admixtures such as calcium chloride promote

1. A permanent retardation ✓
2. B faster setting and early strength (use restricted in reinforced concrete) ✓
3. C only colour change ✓
4. D sulphate immunity ✓

Fly ash as supplementary cementitious material exhibits

1. A hydraulic set without water ✓
2. B only filler with no reaction ✓
3. C pozzolanic activity consuming Ca(OH)2 ✓
4. D negative strength always ✓

Ground granulated blast furnace slag (GGBS) in concrete typically

1. A increases early heat greatly ✓
2. B improves sulphate resistance and reduces permeability ✓
3. C eliminates need for curing ✓
4. D prevents all shrinkage ✓

Silica fume is used to produce

1. A only lean mixes ✓
2. B high-strength, low-permeability concrete ✓
3. C zero cement mortar ✓
4. D only road sub-base ✓

Maturity of concrete relates strength development to

1. A only calendar days regardless of temperature ✓
2. B time-temperature history ✓
3. C aggregate colour ✓
4. D formwork type ✓

Curing of concrete is essential to

1. A dry surface rapidly ✓
2. B prevent any hydration ✓
3. C maintain moisture for continued hydration and strength gain ✓
4. D remove all cement paste ✓

Minimum curing period for ordinary concrete is commonly

1. A 2 hours only ✓
2. B 7 to 14 days depending on cement type and exposure ✓
3. C no curing if high w/c ✓
4. D only in winter ✓

Steam curing is used in precast plants to

1. A reduce strength ✓
2. B increase w/c ✓
3. C prevent hydration ✓
4. D accelerate strength gain by elevated temperature ✓

Shrinkage in concrete includes

1. A only elastic deformation under load ✓
2. B only aggregate crushing ✓
3. C plastic, drying and autogenous components ✓
4. D thermal expansion only ✓

Creep in concrete is

1. A time-dependent deformation under sustained load ✓
2. B instant elastic strain only ✓
3. C reversible upon unloading immediately ✓
4. D only in steel ✓

Modulus of elasticity of concrete is influenced by

1. A only bar diameter ✓
2. B only wind ✓
3. C paint colour ✓
4. D aggregate stiffness, w/c and age ✓

Standard cube compressive strength of concrete is tested at

1. A 1 hour only ✓
2. B 28 days on 150 mm cubes (common practice) ✓
3. C after carbonation only ✓
4. D on wet cubes without caps ✓

Characteristic compressive strength fck means

1. A value below which not more than 5% of results are expected to fall ✓
2. B average of all tests ✓
3. C minimum ever recorded ✓
4. D maximum strength ✓

Split tensile test on concrete cylinder measures

1. A compressive strength directly ✓
2. B shear only ✓
3. C indirect tensile strength ✓
4. D modulus of elasticity ✓

Flexural strength of concrete is often estimated as

1. A equal to cube strength ✓
2. B zero for RCC ✓
3. C 0.7√fck MPa for plain concrete (approximate code relation) ✓
4. D twice compressive strength ✓

Rebound hammer (Schmidt hammer) provides

1. A exact w/c ratio ✓
2. B chloride content ✓
3. C non-destructive estimate of surface hardness/strength ✓
4. D steel stress ✓

Ultrasonic pulse velocity test in concrete detects

1. A only steel corrosion directly ✓
2. B cracks, voids and quality variations by wave speed ✓
3. C only slump ✓
4. D cement brand ✓

Core test on existing concrete gives

1. A only theoretical mix strength ✓
2. B in-situ compressive strength after trimming and capping ✓
3. C aggregate FM ✓
4. D slump of original pour ✓

Honeycombing in concrete is caused by

1. A proper vibration ✓
2. B low w/c with good workability ✓
3. C inadequate compaction and mortar loss at form faces ✓
4. D sufficient cover ✓

Efflorescence on concrete surface is due to

1. A high strength only ✓
2. B migration and crystallization of soluble salts ✓
3. C air entrainment ✓
4. D proper curing ✓

Carbonation of concrete reduces

1. A pH of pore water, risking depassivation of embedded steel ✓
2. B compressive strength always to zero ✓
3. C aggregate volume ✓
4. D formwork reuse ✓

Chloride attack on reinforced concrete promotes

1. A only sulphate expansion ✓
2. B only alkali silica gel ✓
3. C corrosion of reinforcement ✓
4. D instant gain in strength ✓

Sulphate attack on concrete expands due to

1. A only drying shrinkage ✓
2. B only air bubbles ✓
3. C formation of ettringite and gypsum in presence of sulphates ✓
4. D carbonation ✓

High-performance concrete (HPC) typically features

1. A high w/c and lean cement ✓
2. B no curing ✓
3. C only manual mixing ✓
4. D low w/c, silica fume and strict quality control ✓

Self-compacting concrete (SCC) is characterized by

1. A zero cement ✓
2. B high flow without segregation under its own weight ✓
3. C cannot pass reinforcement ✓
4. D requires heavy vibration ✓

Lightweight aggregate concrete uses aggregates such as

1. A only dense granite ✓
2. B expanded clay, pumice or foamed slag ✓
3. C steel balls ✓
4. D pure cement paste ✓

No-fines concrete (porous concrete) contains

1. A equal sand and cement only ✓
2. B only water ✓
3. C coarse aggregate and cement paste without fine aggregate ✓
4. D steel fibres only ✓

Fibre reinforced concrete improves

1. A only colour ✓
2. B only setting time ✓
3. C eliminates need for steel always ✓
4. D crack control, impact resistance and toughness ✓

Ready-mix concrete advantages include

1. A always higher w/c ✓
2. B no transit time limits ✓
3. C consistent quality, controlled batching and reduced site labour ✓
4. D no testing needed ✓

Transit mixer drum rotation during delivery

1. A dries concrete ✓
2. B removes all air ✓
3. C increases temperature to 100°C ✓
4. D prevents segregation and initial set ✓

Volume batching on site is less accurate than

1. A random guessing ✓
2. B no batching ✓
3. C weight batching using calibrated scales ✓
4. D colour matching ✓

Design mix concrete is proportioned to achieve

1. A arbitrary cement always maximum ✓
2. B zero strength check ✓
3. C only appearance ✓
4. D target mean strength and workability at minimum cost ✓

Target mean strength for mix design exceeds fck by

1. A margin depending on grade and site control (k·σ) ✓
2. B zero always ✓
3. C 50% always ✓
4. D no statistical basis ✓

Maximum w/c ratio for durable concrete in severe exposure is

1. A 0.80 typical ✓
2. B 1.0 ✓
3. C low (often 0.40–0.45 per code tables) ✓
4. D unlimited ✓

Minimum cement content in a mix is specified to ensure

1. A only colour ✓
2. B adequate paste for durability and workability ✓
3. C only aggregate grading ✓
4. D zero cohesion ✓

Gap-graded concrete uses

1. A perfect continuous grading only ✓
2. B no coarse aggregate ✓
3. C only silt ✓
4. D a deliberate lack of certain intermediate sizes ✓

Soundness test of cement (Le Chatelier or autoclave) detects

1. A uncombined lime and magnesia causing expansion ✓
2. B fineness only ✓
3. C aggregate shape ✓
4. D slump ✓

Consistency of cement paste is measured by

1. A Vicat apparatus ✓
2. B slump cone ✓
3. C compaction factor only ✓
4. D Los Angeles machine ✓

Loss on ignition of cement indicates

1. A aggregate moisture ✓
2. B steel yield stress ✓
3. C pre-hydration or carbonation of stored cement ✓
4. D slump loss ✓

Compressive strength of cement is tested on

1. A neat cement paste cubes only ✓
2. B cement mortar cubes (1:3 sand, standard sand) ✓
3. C concrete cylinders only ✓
4. D bricks only ✓

Lime in building materials is produced by

1. A calcination of limestone (CaCO3) to quicklime ✓
2. B hydration of cement only ✓
3. C grinding aggregate ✓
4. D air entrainment ✓

Hydrated lime (slaked lime) is used in

1. A masonry mortars and plasters ✓
2. B prestressed cables ✓
3. C only coarse aggregate ✓
4. D only bitumen roads ✓

Timber seasoning reduces

1. A density to zero ✓
2. B fire resistance always negatively ✓
3. C all strength ✓
4. D moisture content to improve strength and reduce shrinkage ✓

Heartwood in timber is generally

1. A more durable and resistant to decay than sapwood ✓
2. B always weaker and wetter ✓
3. C identical to bark ✓
4. D unsuitable for any use ✓

Bricks classified as first class should have

1. A high absorption unlimited ✓
2. B irregular dimensions ✓
3. C uniform shape, sharp edges and minimum crushing strength per code ✓
4. D efflorescence encouraged ✓

Water absorption of good quality burnt clay bricks should be

1. A above 50% preferred ✓
2. B zero always ✓
3. C unlimited ✓
4. D moderate and within code limits (often below about 20%) ✓

Efflorescence in bricks is caused by

1. A high compressive strength ✓
2. B proper firing temperature ✓
3. C low absorption ✓
4. D soluble salts migrating to surface ✓

Fly ash bricks are made by

1. A kiln firing clay only ✓
2. B only wood chips ✓
3. C only steel slag melting ✓
4. D compressing fly ash, lime and gypsum or cement ✓

Bitumen grade for road works is often specified by

1. A penetration or viscosity at standard temperature ✓
2. B slump mm ✓
3. C compressive strength MPa ✓
4. D Proctor density only ✓