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CIVIL ENGINEERING GLOSSARY

394 essential terms — every one cross-linked to its IS code

From dead load to development length, slump test to shear wall — the working vocabulary of Indian civil engineers, each with its IS / IRC code reference, formula, typical values, and free calculator.

Concrete

55

Air-Entrained Concrete

Concrete with deliberately introduced microscopic air bubbles for freeze-thaw + workability

Alkali-Aggregate Reaction (AAR/ASR)

Expansive internal reaction between cement alkalis and reactive aggregate silica

Bleeding of Concrete

Upward migration of mix water to the concrete surface. Excessive bleeding causes weak top layer, dusting.

Carbonation Depth & Carbonation of Concrete

Depth from concrete surface to which atmospheric CO₂ has neutralized the alkalinity of the cement paste — drives rebar corrosion timeline once it reaches the cover.

Flowable cement-water (±sand/admixture) mix injected to fill voids + bond

Chloride Content Limit in Concrete

Maximum acid-soluble chloride permitted in concrete to prevent rebar corrosion — per IS 456 Cl. 8.2.5.2 and Table 7.

Weak unplanned joint where fresh concrete is placed on concrete that has set

Concrete Admixtures

Plasticizers, accelerators, retarders per IS 9103

Min concrete from rebar to surface (15-50mm per exposure)

Concrete Curing

Min 7 days for OPC, 10 days for PPC, 14 days for sulphate-resistant

Concrete Grades (M15-M80)

M20=20 N/mm² characteristic strength at 28 days

Concrete Mix Design

Proportioning of cement, water, aggregates per IS 10262

Concrete Placing Temperature

Should not exceed 30°C as per IS 7861. Above this, retarders, ice chips, or chilled water are required.

Construction Joint

Planned stoppage between concrete pours, located + treated for monolithic bond

Contraction Joint (Control Joint)

Pre-formed weak plane that localises shrinkage cracking to a chosen line

Creep & Shrinkage (Concrete)

Time-dependent deformation of concrete under sustained load

Creep Coefficient of Concrete (θ)

Ratio of creep strain to elastic strain under sustained load — per IS 456 Cl. 6.2.5.1 — depends on age at loading and humidity.

Cube Test (Compressive Strength)

150mm cube compressive strength test at 7/28 days (IS 516)

Damp-Proof Course (DPC)

Impervious horizontal barrier at plinth stopping rising damp into walls

Doubly Reinforced Beam

Beam with both tension and compression steel when section depth is limited

Early Age Strength of Concrete

Strength gain at 1, 3, 7, 14 days — typically 16%, 40%, 65%, 90% of 28-day strength for OPC.

fck (Characteristic Strength)

5% probability lower limit at 28 days

Fiber-Reinforced Concrete (FRC)

Concrete with discrete steel, glass, or polymer fibers added to control crack widths and improve toughness.

Formwork Stripping Time (Removal Schedule)

Minimum time before formwork can be safely removed per IS 456 Cl. 11.3 — depends on member type, climate, and concrete strength.

Guniting (Dry-Mix Shotcrete)

Dry cement-sand mix conveyed by air + hydrated at the nozzle, sprayed onto a surface

High Strength Concrete (HSC)

Concrete with characteristic strength above M60. Requires silica fume, low w/c (<0.35), and quality aggregate.

Honeycomb in Concrete

Voids in concrete from poor compaction or formwork leakage. Repair with grouting; severe cases require demolition.

Weak, porous layer of cement fines and water on concrete surface. Must be removed before next pour to ensure bond.

Lightweight Concrete

Concrete with density below 1900 kg/m³, made with lightweight aggregates (LECA, pumice) or foaming agents.

Large-volume pours where heat of hydration + thermal cracking govern

Modulus of Elasticity of Concrete (Ec)

Short-term static modulus of elasticity of concrete per IS 456 Cl. 6.2.3.1 — Ec = 5000√fck (in N/mm² with fck in N/mm²).

Slab supported on two opposite edges, bending in one direction

PCC (Plain Cement Concrete)

Concrete without reinforcement. Used for sub-base, blinding.

Pervious (No-Fines) Concrete

Concrete with little/no fine aggregate giving interconnected voids for drainage

Plastic Shrinkage Cracks

Early surface cracks from rapid moisture loss before concrete sets

Mass concrete with large stones (>150 mm, plums) embedded — used in retaining walls, mass foundations to save cement.

Precast Concrete

Concrete elements cast off-site, then erected

Pumpable Concrete

Concrete designed for pumping — slump 100-150 mm, well-graded fines, no segregation. Up to 350 m vertical placement.

RCC (Reinforced Cement Concrete)

Concrete with steel reinforcement. Per IS 456:2000.

Ready-Mix Concrete (RMC)

Factory-mixed concrete delivered fresh

Ready-Mix Concrete Grades

Plant-mixed concrete delivered fresh to site per IS 4926

Segregation of Concrete

Separation of coarse aggregate from cement paste due to over-vibration, drop height >1.5 m, or low cohesion.

Self-Compacting Concrete (SCC)

Highly fluid concrete that flows under its own weight, fills formwork, and consolidates without vibration.

Shotcrete (Sprayed Concrete)

Concrete sprayed pneumatically onto a surface — used for tunnel lining, slope stabilization, and structural repair.

Shrinkage Strain of Concrete (εcs)

Volumetric strain of concrete due to drying and chemical shrinkage — per IS 456 Cl. 6.2.4.1 — typical value 0.0003 (300 microstrain).

Slump Test / Workability

25-150mm slump per application (IS 1199)

Spalling of Concrete

Flaking/breaking off of concrete cover, often from rebar corrosion or fire

Sulphate Attack on Concrete

Expansive deterioration from sulphate-rich soil/water reacting with cement hydrates

Target Mean Strength

Strength a mix is designed for, above fck by a margin for site variability

Tremie Concrete (Underwater)

Concrete placement under water using a tremie pipe

Tremie Method of Concreting

Underwater concreting through a vertical pipe (tremie) — used for piles, diaphragm walls, and bridge piers in water.

Slab supported on all four edges, bending in both directions

Vacuum Dewatering of Concrete

Removing surplus water from fresh slab concrete by suction for a stronger, harder floor

Waffle Slab (Ribbed Slab)

Two-way ribbed slab with a grid of voids — long spans, low self-weight

Water-Cement Ratio (w/c)

Mass of water to mass of cement. 0.40-0.55 typical.

Steel

35

Bar Bending Schedule (BBS)

Schedule listing bar shapes, sizes, lengths per IS 2502

Steel plate at the bottom of a column transferring axial load to concrete. Thickness governed by bending under bearing pressure.

Binding Wire (Tying Wire)

Soft annealed steel wire used to tie reinforcement bars at intersections

Bolted Connection

Joining steel members with bolts; checked for shear, bearing + tension

Weld between two pieces in the same plane — V-groove, U-groove, or square. Used for full-strength connections.

Chequered / Floor Plate

Steel plate with raised pattern for floors, stair treads

Compression Member (Strut/Column)

Steel member carrying axial thrust; capacity governed by buckling, not yield

Crank Bar (Bent-up Bar)

Reinforcement bent up near supports to resist hogging moment + shear

Development Length / Anchorage

Length of bar embedment to develop full strength

Triangular cross-section weld joining two surfaces at right angles. Throat thickness = 0.7× leg size.

fy (Yield Strength of Steel)

415/500/550 N/mm² for Fe415/500/550

Galvanizing / Zinc Coating

Zinc coating on steel for corrosion protection per IS 2629

Plate at a steel truss/frame joint connecting multiple members. Designed for block shear, tension, and weld capacity.

Hollow Section (SHS / RHS / CHS)

SHS, RHS, CHS hollow steel sections for structural use

HSFG Bolt (High-Strength Friction-Grip)

Pre-tensioned high-strength bolt transferring load by friction, not bearing

IS 1786 — Parts List (High Strength Deformed Steel Bars)

Complete list of all 1 parts of IS 1786 — high strength deformed steel bars.

ISA (Indian Standard Angle)

L-shaped angle section

ISHB (Indian Standard H-Beam)

H-section used for columns

ISLB (Indian Standard Light Beam)

Indian Standard Light Weight Beam

ISMB (Indian Standard Medium Beam)

Indian Standard Medium Weight Beam — most common I-section

ISMC (Indian Standard Medium Channel)

Channel section per IS 808

ISWB (Indian Standard Wide Flange Beam)

Wide flange beam — better for bending

Length of overlap to transfer force between bars (40-60d typical)

Lateral-Torsional Buckling

Unbraced beam failing by sideways deflection + twist before reaching full capacity

Mechanical splice connecting two rebars without lap. Saves 50-70% steel where lap length would be excessive.

Rebar Weight Calculation

Weight = D²/162.2 kg/m where D is dia in mm

Shear Stud / Shear Connector

Welded stud transferring horizontal shear between steel beam and concrete slab in composite construction.

Steel Fabrication

Cutting, welding, and assembly of structural steel members

Steel Plate Weight

MS plates per IS 2062. Weight = L×B×t×7850 kg/m³

Plate welded to steel beam web preventing buckling. Required at supports and points of concentrated load.

Structural Steel Sections

ISMB/ISLB/ISWB/ISHB beams, ISMC channels, ISA angles per IS 808

Steel member carrying axial pull; capacity is least of yielding, rupture, block shear

TMT Steel Bar (Fe415/Fe500/Fe550)

Thermo Mechanically Treated bars per IS 1786. Fe500 most common.

Welding (Steel Joining)

Per IS 816 (manual) and IS 9595 (welding procedure)

Yield Strength (fy)

Stress at which steel begins permanent deformation. Common Indian rebar grades: Fe415, Fe500, Fe550, Fe550D.

Structural

48

Anchor Bolt / Foundation Bolt

Bolts cast into concrete foundation to anchor steel columns

Bar Curtailment (Reinforcement Curtailment)

Stopping reinforcement where it is no longer needed, with code-required extensions

Beam Design (RCC/Steel)

Flexure + shear design per IS 456 (RCC) or IS 800 (steel)

Internal moment that causes a member to bend; basis of flexural design

Biaxial Bending

Column bent about both principal axes simultaneously plus axial load

Buckling / Slenderness

Compression member instability under axial load

Beam fixed at one end and free at the other. Maximum moment at fixed end; deflection 4× simply-supported.

Clear Span vs Effective Span

Clear distance between supports vs the span used in analysis (effective span)

Column Design (RCC)

Axial + uniaxial/biaxial bending per IS 456

Column Interaction Diagram

Curve of safe axial-load vs moment combinations for a reinforced column

Composite Beam (Steel-Concrete)

Steel beam + concrete slab made to act as one section via shear connectors

Beam where span/depth ratio is below 2.5 (simply supported) or 2.0 (continuous). Strut-and-tie design per IS 456 Cl. 29.

Reinforced concrete wall cast in panels under bentonite slurry — used for deep basements, metro stations.

Effective Length of Column

Equivalent pin-ended length of a column for buckling, set by end restraint

Expansion Anchor / Chemical Anchor

Post-installed anchors in hardened concrete

Expansion Joint

Gaps to accommodate thermal/structural movement

Fire Resistance Rating

Time a member resists fire — 1, 2, 3, 4 hour ratings

Slab supported directly on columns

Footing / Foundation

Spread footing, combined, raft, pile per IS 456 + IS 1904

Beam at ground level on top of pile cap or column footing carrying superstructure dead load.

Graph of a response at one point as a unit load moves across the structure

Beam at the edge of a slab — flange on one side only. Found at building perimeters.

Lever Arm (Internal Moment Arm)

Distance between concrete compression + steel tension resultants in a bending section

Horizontal beam over a door/window opening transferring wall load above to side walls. Min bearing 150 mm each side.

Minimum Eccentricity

Code-mandated minimum load eccentricity a column must always be designed for

Moment Distribution Method

Iterative hand method to analyse indeterminate continuous beams + frames

Moment of Inertia (Second Moment of Area)

Geometric property quantifying a section's resistance to bending

Secondary moments due to axial load × lateral deflection

Percentage of Steel (Reinforcement Ratio)

Area of reinforcement as a % of concrete section — controls ductility + economy

Beam at plinth level connecting columns and supporting wall above. Prevents differential settlement and ties columns.

Rigid-jointed beam-column frame giving large clear-span column-free space

Post-Tensioning (PT)

Steel tendons stressed AFTER concrete hardens via hydraulic jacks. Used for long-span slabs and bridges.

Post-Tensioning / PT

Concrete reinforced with high-tensile steel tendons under tension

Radius of Gyration

√(I/A): distributes a section's area for buckling/slenderness calculation

Wall to retain earth pressure

Section Modulus

Section property relating bending moment to extreme-fibre bending stress

Internal force acting transverse to the member axis; governs stirrup design

Shear Span (a/d Ratio)

Distance from support to load over depth — distinguishes beam vs deep-beam action

RCC wall to resist lateral loads (wind/seismic)

Interlocking steel/concrete piles forming a continuous wall — used for retaining temporary excavations and waterfront.

Shoring / Underpinning

Temporary support during excavation or foundation work

Slab Design (RCC)

One-way (Lx/Ly>2) or two-way slab design per IS 456

Slenderness Ratio

Effective length ÷ radius of gyration; decides column buckling behaviour

Staircase Design

Staircase design per IS 456. Riser 150-180mm, tread 250-300mm.

Beam cast monolithically with slab — flange acts in compression. Most efficient where slab is on the compression side.

Beam connecting two foundations or columns to resist lateral movement. Common in pile caps and combined footings.

Steel truss for roofs/bridges per IS 800

Strengthening of an existing foundation by extending it deeper or wider — needed when settlement or load increase occurs.

Loads

15

Construction Load

Loads during construction — formwork, scaffolding, stockpiled materials, workers. IS 875 Cl. 3.1.4.

Permanent load due to self-weight of structure (IS 875 Part 1)

Service load multiplied by partial safety factor for ultimate limit state. 1.5(DL+LL), 1.2(DL+LL+EL), 1.5(DL+EL), etc.

Repeated load below yield that causes failure after many cycles. Critical for bridges, cranes, machinery foundations.

Suddenly applied or vibratory load — bridges, lift wells, machine foundations. IS 875-2 Cl. 4.6.

IS 875 — Parts List (Design Loads (Other than Earthquake))

Complete list of all 6 parts of IS 875 — design loads (other than earthquake).

Live Load / Imposed Load

Variable load due to occupancy/use (IS 875 Part 2). 2-5 kN/m² typical.

Load Combinations

DL+LL, 1.5(DL+LL), DL+LL+WL etc per IS 456/IS 800

Load that traverses the structure — IRC vehicle classes for bridges (Class A, B, AA, 70R).

Point Load / Concentrated Load

Load applied at a single point (kN)

Seismic / Earthquake Load

Lateral force from earthquake (IS 1893). Zones II–V in India.

Snow accumulation load (IS 875 Part 4)

Stresses from temperature change. ΔT × α × E. Coefficient of thermal expansion: concrete 10×10⁻⁶/°C, steel 12×10⁻⁶/°C.

Uniform Distributed Load (UDL)

Load spread evenly across length or area (kN/m or kN/m²)

Lateral wind pressure on building (IS 875 Part 3). Basic wind speed 33-55 m/s in India.

Geotechnical

36

Atterberg Limits

Liquid limit, plastic limit + shrinkage limit defining fine-soil consistency

Borehole Log (Bore Log)

Depth-wise record of strata, SPT N-values, samples + water table in a borehole

California Bearing Ratio (CBR)

Subgrade strength index for pavement design

Cohesion & Friction Angle

Mohr-Coulomb shear-strength parameters. Clay: cohesive (c). Sand: frictional (φ). C-φ soil has both.

Cone Penetration Test (CPT)

Continuous in-situ probe giving cone resistance + sleeve friction with depth

Consolidation Test (Oedometer)

Lab test giving compressibility + rate of long-term clay settlement

Removing groundwater from excavations during construction

Dynamic Cone Penetration (DCP)

Quick field test for relative soil density — drop weight repeatedly, measure penetration per blow.

Effective Stress

Stress carried by the soil skeleton — total stress minus pore water pressure

Expansive Soil (Black Cotton Soil)

Montmorillonitic clay that swells when wet + shrinks when dry, cracking structures

Factor of Safety (FoS)

Ratio of ultimate capacity to design load. Bearing: 2.5-3.0. Slope: 1.5. Pile: 2.5. Overturning: 2.0.

Field Density Test

On-site test of achieved compaction (sand-replacement / core-cutter)

Geotechnical Site Investigation

Boring, sampling + testing programme that characterises the ground for design

Geotextile / Geomembrane

Synthetic fabrics for drainage, filtration, soil reinforcement

Ground Improvement

Techniques that strengthen/stiffen weak ground to avoid deep foundations

IS 2720 — Parts List (Methods of Test for Soils)

Complete list of all 19 parts of IS 2720 — methods of test for soils.

Lateral Earth Pressure

Horizontal soil pressure on retaining structures. Active (Ka), at-rest (K0), passive (Kp). Computed by Rankine or Coulomb theory.

Maximum Dry Density (MDD)

Highest dry density a soil reaches at OMC for a given compaction effort

Modulus of Subgrade Reaction

Soil 'spring stiffness' (pressure per unit settlement) for raft + pavement design

Optimum Moisture Content (OMC)

Water content at which a soil reaches its maximum dry density on compaction

Pile Foundation

Deep foundation transferring load to firm strata via piles

Plasticity Index

Liquid limit minus plastic limit; the range of plastic behaviour of a soil

Plate Load Test

Field test for safe bearing capacity using a steel plate (300/450/600/750 mm) loaded incrementally per IS 1888.

Pore Water Pressure

Water pressure in soil voids; reduces effective stress and hence strength

Proctor Compaction Test

Lab test giving the soil compaction curve (OMC + MDD)

Retaining Wall Types

Walls retaining earth — gravity, cantilever, counterfort, diaphragm

Safe Bearing Capacity (SBC)

Max safe pressure soil can take. 100-500 kN/m² typical.

Vertical downward movement of a foundation under load. Total ≤25 mm for raft, ≤50 mm for footings (IS 1904).

Slope Stability

Analysis of factor of safety against landslide. Methods: Bishop's, Fellenius, Janbu. FoS ≥ 1.5 for permanent slopes.

Soil Classification

Per IS 1498 / Unified Soil Classification System

Soil Liquefaction

Loss of soil shear strength under cyclic loading (earthquake) — saturated loose sand behaves like liquid.

Soil Permeability Test

Measures the coefficient of permeability k governing seepage + dewatering

Soil Stabilisation

Improving weak soil's strength/durability by additives or mechanical means

Standard Penetration Test (SPT)

Soil density test in borehole per IS 2131

Compacted granular columns that reinforce, drain + densify soft ground

Vane Shear Test

Test for undrained shear strength of soft cohesive soils — four-bladed vane rotated until soil shears.

Foundation

12

Bored Cast-in-situ Pile

Pile constructed by drilling a hole and filling with concrete + reinforcement. Diameter 300-2400 mm, depth up to 60 m.

Temporary watertight enclosure to dewater an area for in-the-dry construction

Combined Footing

Single footing supporting two or more columns — used when columns are close (<2 m) or property line restricts.

Isolated Footing

Footing supporting a single column. Most common for low-rise buildings on soils with adequate bearing capacity.

Negative Skin Friction (Downdrag)

Downward soil drag on a pile when surrounding soil settles more than the pile

Reinforced concrete cap connecting tops of piles to the column. Designed as a deep beam or strut-and-tie.

Field test verifying a pile's safe capacity by applying test load + measuring settlement

Raft Foundation

Single thick slab covering the entire building footprint — for soft soil, heavy loads, or when isolated footings overlap.

Stepped Footing

Footing with stepped/tapered profile — saves concrete on large footings while maintaining bearing pressure distribution.

Continuous footing under a load-bearing wall — width = wall thickness + 150 mm projection on each side.

Under-Reamed Pile

Bored pile with one/more enlarged bulbs — the standard remedy for expansive soil

Well Foundation

Hollow shaft sunk through soft soil to firm strata, filled with concrete — used for major bridge piers in rivers.

Design

28

Balanced Section

Section where concrete crushes (0.0035) and steel yields (fy) simultaneously. xu = xu,max per IS 456.

Crack Width (RCC)

Limiting calculated surface crack width for durability + serviceability

Cracked Section Analysis

Analysis ignoring concrete in tension below NA. Required for serviceability (deflection, crack width) per IS 456 Annex F.

Deflection Limits

Span/250 (final), span/350 (after partition). IS 456 Cl. 23.2 — use span/depth ratios for control.

Effective Flange Width (T-Beam)

The slab width acting with a beam web as a T/L-beam compression flange

Effective Span (Beams & Slabs)

Span used for design calculation — per IS 456 Cl. 22.2 — lesser of (clear span + effective depth) and (centre-to-centre distance of supports).

Flexible Pavement

Layered bituminous pavement that spreads wheel load gradually to the subgrade

Formwork / Shuttering

Stripping time: slab 7d, beam soffit 14d, column 16-24h

FSI / FAR (Floor Space Index)

Ratio of total built-up floor area to plot area; the master density control

Granular Sub-Base (GSB)

Graded-aggregate layer above subgrade providing drainage + load spreading

Limit State Design (LSD)

Modern design philosophy ensuring two limit states: ULS (collapse) and SLS (deflection, cracking). IS 456 Cl. 35.

Ratio of steel to concrete modulus, used in working-stress + cracked-section analysis

Modulus of Elasticity (E)

Concrete: Ec = 5000√fck MPa. Steel: Es = 2×10⁵ MPa. Modular ratio m = Es/Ec.

Moment of Resistance

The bending moment a section can safely resist at its design limit state

Moment Redistribution

Adjusting elastic moments to exploit ductility + even out beam reinforcement

Line of zero strain in a flexural member. Above it: compression. Below: tension.

Partial Safety Factor

Multiplier on loads (γf) and divisor on materials (γm). Concrete γm=1.5, Steel γm=1.15. Dead γf=1.5, Live γf=1.5.

Two-way shear where a column 'punches' through a slab/footing

Rebar Spacing (Min/Max)

Min spacing = bar dia or 25mm. Max = 3d or 300mm.

Reinforcement Limits (Min/Max %)

Min 0.12% slab, 0.85% beam tension; max 4% column per IS 456

Concrete slab pavement carrying load mainly by its own flexural rigidity

Scaffolding & Safety

Scaffolding safety per IS 3696

Scaffolding Types

Temporary structures for working at height

Setback (Building Margin)

Mandatory open distance between building and plot boundary

Stirrups / Shear Reinforcement

Shear reinforcement in beams/columns

Structural Thumb Rules

Rules of thumb for slab/beam/column sizing

Transverse outward-to-inward slope on a curve to counter centrifugal force

Working Stress Method (WSM)

Older method using permissible stresses well below yield. Now restricted to special structures (water tanks).

Seismic

15

Flexible bearings at the base that decouple a structure from ground shaking

Horizontal seismic force at the base of a structure. Vb = Ah × W, where Ah = (Z/2)(I/R)(Sa/g). IS 1893 Cl. 7.5.

Energy dissipation in structure. RCC: 5% (design). Steel: 2-3%. Higher damping → smaller seismic response.

Ductile Detailing (Seismic)

Special seismic detailing per IS 13920

Earthquake / Seismic Zones (II-V)

Zone II (least)-V (most) per IS 1893

Importance Factor (I)

Multiplier on seismic force based on building criticality. Hospitals: 1.5. Schools: 1.5. Residential: 1.0.

IS 1893 — Parts List (Criteria for Earthquake Resistant Design)

Complete list of all 8 parts of IS 1893 — criteria for earthquake resistant design.

Pushover Analysis

Nonlinear static analysis tracing a structure's capacity + hinge sequence

Response Reduction Factor (R)

Reduces elastic seismic forces to design forces accounting for ductility. SMRF: 5.0. OMRF: 3.0. Shear wall: 4.0.

Response Spectrum

Plot of peak structural response vs. natural period for an earthquake. IS 1893 Fig. 2 gives design spectra for 5% damping.

Soft Storey / Stilt Floor

Storey with stiffness <70% of the storey above — typical of stilt parking. IS 1893 Cl. 7.10 mandates 2.5× design force.

Soil-Structure Interaction (SSI)

Interaction between flexible soil and structure under earthquake. Considered for tall buildings on soft soils per IS 1893.

Special Moment Resisting Frame (SMRF)

Frame designed and detailed for high ductility per IS 13920. R = 5.0. Required in Zone IV/V for important buildings.

Relative lateral displacement between two adjacent floors under lateral load

Strong-Column Weak-Beam

Capacity-design rule forcing ductile beam hinging before brittle column failure

Materials

46

Autoclaved Aerated Concrete blocks — density 550-650 kg/m³, fire-resistant, light, used for non-load-bearing walls.

Aggregate Crushing Value (ACV)

Percentage fines under a standard gradual crushing load — aggregate strength

Aggregate Impact Value (AIV)

Percentage fines produced under standard impact — toughness of aggregate

Aggregates (Fine & Coarse)

Coarse (10-40mm) and fine (sand) aggregates per IS 383

Bamboo Construction

Bamboo as a sustainable building material per IS 6874

Block Board / Particle Board

Engineered wood products for furniture and panels

Brick / Block Masonry

Bricks per IS 1077, blocks per IS 2185

Bulking of Sand

Volume increase of damp sand due to moisture films separating particles

Cement Types & Grades

OPC 33/43/53 PPC PSC SRC and rapid hardening cement varieties per IS standards

White salt deposit on masonry/concrete surfaces from soluble-salt migration

High-strength resin grout for crack injection, anchoring + precision base-plate grouting

Fineness Modulus

Single index of aggregate coarseness from cumulative sieve retention

Fineness of Cement

Particle fineness of cement controlling its rate of hydration + strength gain

Flakiness & Elongation Index

Percentage of flat/elongated particles — controls aggregate particle shape

Fly Ash (Pulverized Fuel Ash)

Coal-combustion byproduct used as supplementary cementitious material in cement mortar and concrete. Covered by IS 3812 (Part 1 — pozzolana; Part 2 — admixture). Also used in PPC (IS 1489) and fly-ash bricks (IS 12894/IS 13757).

Fly Ash Brick / Block

Fly ash + lime + gypsum brick. Eco-friendly alternative to clay brick.

GGBS (Ground Granulated Blast-furnace Slag)

Cementitious by-product of iron production. Replaces 25-70% of OPC for sulphate resistance and lower hydration heat.

Hard igneous stone — compressive strength 100-250 MPa. Used for flooring, kitchen tops, bridge cladding.

Fine-grained limestone from Kota, Rajasthan — popular flooring stone. Density 2400 kg/m³, low water absorption.

Lime-based mortar — breathable, flexible, used for heritage + traditional masonry

Los Angeles Abrasion Value

Wear resistance of aggregate measured by tumbling with steel charge

Metamorphic limestone — softer than granite (60-100 MPa). Acid-sensitive — avoid for kitchens and outdoor.

Marine Plywood (BWP)

Boiling water proof plywood for marine and exterior use per IS 710

Ordinary Portland Cement (OPC)

33/43/53 grade Portland cement. 53 most common for structural use.

Paint & Coatings

Wall paint, primer, putty, coatings

Precast concrete blocks for paving — M30 to M40, thickness 60-100 mm depending on traffic load.

Polymer-Modified Mortar

Cement mortar with polymer (SBR/acrylic) for high bond + low permeability repair

Portland Pozzolana Cement (PPC)

Cement blended with fly ash. More durable than OPC.

Portland Slag Cement (PSC)

Cement blended with blast furnace slag

Rapid Hardening Cement

High early strength cement per IS 8041

Sand (River / M-Sand)

Fine aggregate. River sand or manufactured sand.

Sandwich Panel / EPS Panel

Insulated composite panels for walls and roofs

Setting Time of Cement

Time for cement paste to lose plasticity (initial) + fully set (final)

Silica Fume / Microsilica

Ultra-fine silica by-product, replaces 5-10% cement. Drastically reduces permeability — used in HSC, marine concrete.

Silt Content of Sand

Proportion of clay/silt fines in sand that weakens cement bond if excessive

Soundness of Cement

Cement's resistance to delayed expansion from free lime/magnesia

Specific Heat Capacity (c)

Heat required to raise 1 kg of a material by 1 °C, in J/kg·K. High c × density = high thermal mass = slow temperature swings indoors.

Standard Consistency of Cement

Water % giving a cement paste of reference stiffness (basis for setting/soundness tests)

Sulphate Resistant Cement (SRC)

Cement for sulphate-rich soils per IS 12330

Thermal Conductivity (k-value)

Heat conducted through a unit thickness of material per unit area per °C temperature difference, in W/m·K

Thermal Properties of Materials

Thermal conductivity, specific heat, density, and emissivity values that govern heat transfer through building materials

Tile (Floor / Wall / Roof)

Floor/wall/roof tiles per various IS codes

Unplasticised polyvinyl chloride frames — corrosion-free, thermal-insulating, replacing aluminum in residential.

Water Absorption (Aggregate & Brick)

Percentage water a porous material soaks up — a durability + mix-control index

White Portland Cement

White cement for decorative work, terrazzo, white concrete per IS 8042

Wood Plastic Composite — termite-proof, water-resistant board for cabinets and outdoor cladding.

QA / QC

21

As-Built Drawing

Final drawing reflecting actual constructed condition — handed to the client at project closeout.

Concrete Core Test

Drilled cylindrical core tested for in-situ concrete strength when cubes are in doubt

Cover Block (Spacer)

Precast/plastic spacer that holds reinforcement at the specified clear cover

Field Quality Plan (FQP)

Project-specific QC document covering all activities — test methods, acceptance criteria, sampling rate.

Flexural Strength of Concrete (Modulus of Rupture)

Tensile strength in bending from a beam test; governs pavement slab design

Half-Cell Potential Survey

Non-destructive electrochemical mapping of reinforcement corrosion probability

Mandatory inspection checkpoint that must be cleared before work proceeds — unlike a witness point.

Inspection Test Plan (ITP)

Document listing every inspection/test checkpoint for an activity with frequency, criteria, and responsible party.

Marshall Stability

Test fixing optimum bitumen content + strength of a bituminous mix

Method Statement

Step-by-step procedure for a construction activity — safety, equipment, sequence, QC checkpoints.

Mill Test Certificate (MTC)

Manufacturer's certified record of a material batch's chemical + mechanical test results

Non-Conformance Report (NCR)

Report for work not meeting specification

Non-Conformance Report (NCR)

Document raised when work fails to meet specifications. Includes root cause, corrective action, preventive action.

Punch List / Snag List

List of incomplete/defective items at substantial completion that must be rectified before final handover.

QA/QC Inspection

Quality assurance and control checklists/templates

Rebound Hammer Test

Non-destructive test for in-situ concrete strength — surface hardness measured via spring-loaded hammer.

Transferring the design's positions, levels + lines accurately onto the ground

Split Tensile Strength

Indirect tensile strength of concrete from diametral splitting of a cylinder

Integrated electronic survey instrument measuring angles + distances precisely

Ultrasonic Pulse Velocity (UPV) Test

Non-destructive test gauging concrete quality + uniformity from sound-wave speed

Inspection point where the QC engineer is notified but work can proceed if QC is unavailable.

Estimation

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Abstract Estimate

Cost estimate at concept stage based on plinth area or per-bed/per-room rates. ±20% accuracy.

Bill of Quantities (BOQ)

Itemised list of work activities with quantities and unit rates — forms the priced contract document.

BSR — Basic Schedule of Rates

Basic Schedule of Rates

Carpet area plus wall thickness + balconies (≈ plinth area of the unit)

Net usable floor area within walls; the RERA-mandated sale basis

Construction Cost Estimation

Per sqft cost ₹1500-3500 in India

Provision for unforeseen costs. CPWD: 3%. Private: 5-10%. Higher for renovation than new build.

CPWD — Central Public Works Department

Central Public Works Department

Critical Path Method (CPM)

Network scheduling that finds the longest activity chain fixing project duration

Defect Liability Period (DLP)

Post-completion period in which the contractor must rectify defects free of cost

Detailed Estimate

Quantity-based estimate from drawings. Each work item × unit rate × quantity = cost. ±5% accuracy.

DPR — Detailed Project Report

Detailed Project Report

DSR — Delhi Schedule of Rates (CPWD)

Delhi Schedule of Rates (CPWD)

CPWD Works Manual

Earned Value Management (EVM)

Integrating scope, schedule + cost to objectively measure project performance

Earnest Money Deposit (EMD)

Refundable bid security a tenderer deposits to confirm a genuine offer

Extension of Time (EoT)

Contractual grant of extra completion time for excusable (non-culpable) delay

IRUSSOR — Indian Railways Unified Standard Schedule of Rates

Indian Railways Unified Standard Schedule of Rates

Horizontal (lead) + vertical (lift) distance materials/earth are conveyed, priced extra

Liquidated Damages (LD)

Pre-agreed sum deducted per period of contractor delay beyond completion date

Material Wastage Factors

Cement 2-3%, steel 3-5%, tiles 5-10% typical

Measurement Book (M-Book)

Statutory field record of all work measured, the basis of every running + final bill

Mobilisation Advance

Early advance to the contractor for site set-up, recovered from later bills

Price Escalation (Price Variation)

Contractual adjustment of payments for input-cost changes during the contract

Quantity Estimation

Estimate cement, steel, sand, aggregate for given area

RA Bill — Running Account Bill (Interim Payment)

Running Account Bill (Interim Payment)

Computation of unit rate from material + labour + plant + overhead + profit. Reference: DSR, state SOR, in-house DB.

Retention Money

A percentage deducted from each running bill, released after defect liability

SOR — Schedule of Rates (Government rate book)

Schedule of Rates (Government rate book)

SSR — State Schedule of Rates (PWD)

State Schedule of Rates (PWD)

Services

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Acoustic / Sound Insulation

Sound transmission control via materials/design

Drainage & Sewerage

Building drainage and sewerage systems

Pipe gradient ensuring self-cleansing velocity (>0.6 m/s). 100 mm pipe: 1:60. 150 mm: 1:80. 200 mm: 1:100.

Earthing System (Grounding)

Connecting installations to earth for safety against shock + fault currents

Electrical Installation

Electrical wiring per IS 732, earthing per IS 3043

Fire safety per NBC Part 4 and IS codes

Heat Transfer Modes (Conduction, Convection, Radiation)

Three modes of heat transfer in buildings — conduction (through solids), convection (via fluid/air), radiation (via electromagnetic waves). All three apply to roof, wall, and window heat gain.

HVAC & Air Conditioning

Heating, ventilation, air conditioning

Vertical access shaft to sewer/drainage line. Spacing 30 m on straight runs, at every junction or bend.

Overhead Water Tank (OHT)

Water tank on a staging at sufficient height to provide gravity pressure. Capacity per CPHEEO norms (135-200 LPCD).

Plumbing & Water Supply

Water supply and plumbing per IS codes

R-Value (Thermal Resistance)

Resistance of a material layer or assembly to heat flow, in m²·K/W. Higher R = better insulator. Reciprocal of U-value.

Rainwater Harvesting

Collecting and storing/recharging rainwater. Mandatory in most Indian states for plots above specified area.

Underground anaerobic chamber for primary sewage treatment. Sized at 0.085 m³/person. IS 2470.

Thermal Insulation

Materials and techniques to reduce heat transfer

U-Value (Thermal Transmittance)

Rate of heat transfer through a building element per unit area per °C, in W/m²·K. Lower U-value = better insulation.

Underground Water Sump (UGT)

Below-ground concrete tank receiving water from supply main, pumped to OHT. Typical sizes 5,000-50,000 L.

Finishing

8

Cement-sand mortar coat giving walls a smooth, durable, weather-protective finish

Suspended secondary ceiling for aesthetics, services concealment

Cement-sand layer laid over a base slab to give a level surface for the final floor finish

Flooring & Tiling

Floor finishing — tiles, IPS, marble, granite

Grit Blasting / Surface Preparation

Surface preparation before painting/coating per IS 9012 / SSPC SP-10

Painting & Coatings

Wall and ceiling painting

Damp proof course, membrane, coatings

Waterproofing Systems

Methods to prevent water ingress in roofs, basements, water tanks

Code reference

15

BIS — Bureau of Indian Standards

Bureau of Indian Standards

IRC (Indian Roads Congress)

Codes for roads, bridges, highways

IRC 37 — Flexible Pavement Design

Flexible pavement design guidelines

IRC 58 — Rigid Pavement

Plain jointed rigid pavement design

IRC 6 — Bridge Loads

Loads and load combinations for road bridges

IS 10262 — Concrete Mix Design

Concrete mix proportioning guidelines

IS 1786 — TMT Steel Bars

High Strength Deformed (HSD) Steel Bars specification

IS 1893 — Earthquake Resistant Design

Earthquake resistant design code

IS 1904 — Foundation Design

Code of practice for foundation design

IS 2062 — Structural Steel

Hot rolled medium and high tensile structural steel

IS 2502 — Bar Bending

Bending and fixing of bars for concrete reinforcement

IS 456 — Plain & Reinforced Concrete

Master code for concrete design in India

IS 516 — Concrete Testing

Methods of test for strength of concrete

IS 800 — Steel Structural Design

Master code for steel structural design

IS 875 — Design Loads

Design loads code: Part 1 dead, Part 2 live, Part 3 wind, Part 4 snow, Part 5 special

BIM

14

BEP & EIR — BIM Execution Plan / Exchange Information Requirements

EIR = client requirements (in tender). BEP = how the contractor will deliver them. MIDP/TIDP = the schedule.

BIM Roles — Manager, Coordinator, Modeller

BIM Manager (firm), Project BIM Manager (one project), Information Manager (enforces ISO 19650), BIM Coordinator (clash), Modeller (authoring).

Building Information Modelling (BIM)

ISO 19650 information management with BIM. India has no published IS BIM standard — projects reference ISO directly.

Clash Detection

Automated process of finding spatial conflicts between BIM models. Hard clash (overlap), soft clash (clearance), 4D clash.

COBie (Construction-Operations Building information exchange)

Open spreadsheet format for handing operational data (assets, spaces, warranty) from construction to FM.

Common Data Environment (CDE)

Single trusted location for all project information. Mandatory under ISO 19650 with WIP→Shared→Published→Archived states.

Industry Foundation Classes (IFC)

Open ISO standard file format for BIM exchange. IFC 4.3 ADD2 supports buildings + infrastructure.

ISO 19650 Series

5-part international standard for BIM information management. Parts 1-5: concepts, delivery, operations, exchange, security.

Level of Development (LOD) / LOIN

AIA LOD 100-500 vs BIMForum LOD Spec vs ISO 7817-1 LOIN. Defines geometric/info detail per object per milestone.

BS EN ISO 7817-1

LOD 200 (Schematic Design)

Generic systems, approximate quantities, size, shape, location, orientation. Suitable for schematic stage.

LOD 300 (Detailed Design)

Specific, accurate location, size, shape, quantity, orientation. Suitable for design development and tender.

LOD 400 (Fabrication / Construction)

Element accurate for fabrication, assembly, detailing. Includes connection details, manufacturer data.

LOD 500 (As-Built / FM)

Field-verified element representation suitable for facilities management. Linked to operational data.

Uniclass / OmniClass / Classification

Uniclass 2015 (UK) is the most-used BIM classification on Indian projects. India has no published classification.