Category Archives: Con Tech & RCC Design

Analysis of Structure Building Materials Con Tech & RCC Design Soil Mechanics Solid & Liquid Waste Management Uncategorized

Collection of all IS codes used in Civil Engineering Field.

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The codes are arranged in ascending order of their number. Click the code number to open the PDF file.

173Specification for paving Bitumen
2277Galvanised steel sheets (plain and corrugated)
3303Specification for Plywood for general purposes
4383Specification for Coarse and Fine aggregate for use in mass concrete
5432Specification for Mild steel and medium tensile bars and hard drawn steel wire.
6456Code of practice for plain and reinforced concrete
7457Code of practice for general construction of plain and reinforced concrete for dams and other massive structures.
8515Specification for natural and manufactured aggregate for use in mass concrete.
9516Methods of test for strength of concrete.
10650Specification for Standard sand for testing of Cement
11651Glazed stoneware pipes and fittings
12702Specification for industrial bitumen
13772Specific action for general requirements for enameled cast iron sanitary appliances.
14774Flushing cisterns for water closets and urinals (Other than plastic cistern)-Specifications.
151139Specification for hot rolled mild steel, medium tensile steel and high yield strength steel deformed bars for concrete reinforcement.
161199Methods of sampling and analysof concrete
171199Methods of sampling and analysof ConCrete
181300Phenolic moulding materials.- Specifications
191343Code of practice for prestressed concrete
201566Specification for plain hard drawn steel wire fabric for concrete reinforcement
211629Rules for grading of cut size of timber
221703Water fittings- Copper alloy float valves (horizontal plunger type) – Specification.
231729Cast iron Drain water pipes and fitting
241785Specification for plain hard drawn steel wire for prestressed concrete.
251786Specification for cold twisted steel high strength deformed bars for concrete reinforcement.
261791Specification for batch type concrete mixers
271795Specification for pillar taps for Water supply purposes.
282115Code of practice for flat roof finish: mudphuska
292204Code of practice for construction of reinforced concrete shell roof
302210Criteria for the design of R.C. shell structures and folded plates.
312267Polystyrene moulding and extrusion materials – Specifications
322326Specification for Automatic Flushing Cisterns for Urinals (Other than plastic cisterns)
332387Method of test for aggregates for concrete.
342438Specification for roller pan mixer
352502Code of practice for bending and fixing of bars for concrete reinforcement
362505Specification for concrete vibrators , immersion type
372506Specification for screed board concrete vibrator
382514Specification for concrete vibrating tables
392556Vitreous sanitary appliances (vitreous china) -Specifications
402571Code of practice for laying insitu cement concrete flooring
412633Method of testing uniformity of coating on zinc Coated articles
422645Specification for integral cement water proofing compounds
432645Specification for integral water proofing compounds for cement mortar & concrete
442722Specification for portable swing weigh batchers for concrete (single & double bucket type)
452750Specification for steel scaffoldings.
462751Code of practice for welding of mild steel structures are folded plates
472963Specification for Copper alloy waste fittings for Wash basins and Sinks.
483025Methods of sampling and test (physical and chemical) for water used in industry.
493076Specification for low density polyethylene pipes for potable water Supplies.
503087Particle boards of wood and other ignocellulogic materials (medium density) for general purposes – specifications
513144Methods of test for mineral Wool thermal insulation materials
523201Criteria for design and construction of precast concrete trusses.
533344Specification for pan vibrators
543346Method of the determination of thermal conductivity of thermal insulation materials
553348Specification for fibre insulation boards
563370Code of practice for concrete (Part I to IV structures for storage of liquids
573384Specification for bitumen primer for water proofing and damp proofing
583414Code of practice for design and installation of joints in buildings
593558Code of practice for use of immersion vibrators for consolidating concrete
603935Code of practice for composite construction
614014Code of practice for steel tubular, scaffolding
624031Method of physical tests for hydraulic Cement
634656Specification for form vibrators
644671Expanded polystyrene for thermal insulation purposes
654990Specification for plywood for concrete shuttering work
665382Specification for rubber sealing rings for gas mains, water mains and sewers
675688Methods of test of performed block type and pipe covering type thermal insulations
6810192Specifications for synthetic resin bonded glass fibre (SRBGF) for electrical purposes.
6913592Unplasticised polyvinyl chloride (UPVC) pipes for soil and Waste discharge system for inside and outside building.
7014753Specifications for polymethyl Methacrylate (PMMA) (Arylic) sheets
7114871Specifications for products in fibre reinforced cement – Long corrugated
72 1254 : 1991Corrugated Aluminium Sheet – Specification.
73 8329 : 2000Centrifugally cast (span) ductile Iron pressure Pipes for water, gas and Sewage-Specification.
7410028 (Part II) 1981Selection, installation and maintenance of transformers (Installation)
7510042 – 1981Site Investigations for foundation in gravel – boulder deposit.
7610262 – 1982Recommended Guidelines for concrete mix design.
7710297 – 1982Design and Construction of Floors and Roofs using Precast Reinforced/ Prestressed Concrete Ribbed or Cored Slab units.
7810379 – 1982Field control of moisture and compaction of soils for embankment and subgrade
7910589 – 1983Specification for equipment for subsurface sounding of soils
801080 – 1985Shallow foundations in soils (other than Raft, Ring and Shell) – (2 copies)
811172 – 1993Basic requirements for water supply, drainage and sanitation
8211973-1986Treatment of rock foundations, core and abutment contacts with rock, for embankment dams
831200 (PTΧ)Method of measurements of building and civil engineering works: Ceiling & Lining
8412070 – 1987Design and construction of shallow foundations on rocks
851255 – 1983Installation and maintenance of power cables up to and including 33 kv
8612955 (Part-2) 1990IN-SITU Determination of rock mass deformability using a flexible dilatometer
8713072 ; 1991Sulphur Hexafluoride for Electrical purposes – Specification
8813365 (Part-2) 1992Quantitative classification systems of rock mass – guidelines
891367 (PT-13)Technical supply conditions for threaded steel fasteners pt. 13 hot dip galvanized coating on threaded fasteners
901391 (part 2) 1992Room Air Conditioners (Split Air Conditioners)
9114 862Fibre cement flat sheets – specifications
9214268 : 1995Uncoated stress relieved low relaxation seven-ply strand for prestressed concrete-specification.
9314687: 1999False work for Concrete Structures – Guidelines
941477 (Part-1) 1971Painting of Ferrous metals in buildings (Pretreatment)
951477 (Part-2) 1971Painting of Ferrous metals in buildings (Painting)
961489 (Part-2)1991Portland – Pozzolana cement – specification (calcined clay based)
9714900 – 2000Transparent float glass
9815284 (Part-1) 2003Design and construction for ground Improvement-guidelines-part 1 (stone columns)
991554 (Part 1) 1988PVC insulated (Heavy Duty) Electric Cables
1001566 – 1967Hard – Drawn steel wire Fabric for concrete reinforcement
1011566 – 1982Specification for Hard-Drawn steel wire fabric for concrete reinforcement
1021641 – 1988Fire safety of building (General)
1031888-1992Method of Load Test on Soils
1041893 – 1984Criteria for earthquake resistant design of structures – 2 copies
1051893 (Part – 1) 2002Criteria for Earthquake resistant design of structures – 2 copies
1061893 (Part –1) 2002Criteria for earthquake resistant design of structures
1071893 (Part-1)Explanatory Examples on Indian Seismic
1081904 – 1986Design and construction of foundations in soils
1091904 – 1986Design and Construction of foundations in soils
1102026 (Part – 5) 1994Power Transformers
1112026 (Part I) 1977Specification for power Transformers (General) – 2 Copies
1122026 (Part II) 1977Power Transformers, Part-II Temperature – Rise
1132026 (Part III) 1981Specification for power transformers (Insulation, Levels, Dielectric tests)
1142062-1992Steel for General Structural purposes – specification
1152064 : 1993Selection, Installation and maintenance of sanitary appliances
1162095 (PT-1)Gypsum plaster boards (Pt.1) plain Gypsum plaster boards
1172132-1986Thin welded tube sampling of soils
1182190 : 1992Selection, Installation and maintenance of first-aid fire extinguishers
1192386 (Part-I-V) 1963Test for Aggregates for concrete
1202440:1975Daylighting of Buildings
1212470 (part-1) 1985Installation of Septic Tanks (Part-1) Design criteria and construction
1222502 – 1963Bending and fixing of bars for concrete reinforcement.
1232505 : 1992Concrete vibrators – Immersion Type-General Requirements
1242548 (Part-1Plastic Seats and Covers for Water closets Part 1: Thermo Set Seats and covers – Specifications
1252548 (Part-2)Plastic seats and covers for water closets Part 2: Thermoplastic seats and covers.- Specifications
1262556 (Part -14)Specific requirements of integrated squatting pans.
1272556 (Part -15)Specific requirements of universal water closets.
1282556 (Part-1) Part-1General requirements.
1292556 (Part-2)Specific requirements of Wash-down water closets.
1302556 (Part-3)Specific squatting pans.
1312556 (Part-4)Specific requirements of Washbasins.
1322556 (Part-5)Specific requirements of laboratory sinkS.
1332556 (Part-6) Part-6Specific requirements of Urinals & Partition plates
1342556 (Part-7)Specific requirements of accessories for sanitary appliances
1352571 – 1970Laying IN – SITU cement concrete flooring.
1362571-1970Laying IN-SITU cement concrete flooring
137269 : 1989Ordinary Portland Cement, 33 grade- specification.
1382720 (Part 5) 1985Methods of test for soils
1392720 (Part 8) 1983Methods of test for soils
1402792-1964Design and construction of stone slab over joist floor
141280 – 1978Mild Steel wire for general engineering purposes.
1422911 (Part – III) 1980Design and construction of pile foundations (Under-Reamed piles)
1432911 (Part-4) 1985Design and construction of Pile foundations (Load Test on Piles)
1442950(Part 1) 1981Design and construction of raft foundations (Design)
1452974 (Part I) 1982Design and construction of machine foundations
1463007 (PT.1)Code of practice for laying of asbestos cement sheets: part- 1 corrugated sheets
1473043 – 1987Code of practice for earthing – 2 copies
1483103 – 1975Industrial Ventilation
1493419 – 1989Fittings for rigid non- metallic conduits
1503443 – 1980Specification for Crane rail sections
1513770 (P-1) 1965Concrete structure for the storage of liquids (Part – 1,2)
1523812 – 1981Specification for Fly ash for use as pozzolara and Admixture.
153383 – 1970Coarse and fine aggregates from natural sources for concrete.
1544014 (Part-1) 1967Steel Tubular Scaffolding (Definitions and materials )
1554082-1996Stacking and storage of construction materials and components at site-recommendations. – 2 copies
156432 (Part-I) 1982Mild Steel and medium tensile steel bars and hard – drawn steel wire for concrete reinforcement
157432-1982Mild Steel and medium Tensile Steel Bars and hard-Drawn Steel wire for concrete Reinforcement (part-1) Mild Steel and medium Tensile steel Bars
1584326-1993Earthquake Resistant Design and Construction of Buildings
159459-1992Corrugated and Semi-corrugated Asbestas Cement sheets specification.
1604631 – 1986Laying of Epoxy resin floor toppings
1614885 – 1988Specification for Sewer Bricks
1624926 : 2003Ready Mixed concrete
1634971 – 1968Selection of Industrial floor finishes
1644984 – 1995High Density Polyethylene pipes for water supply – specification
1654985 : 2000Unplasticized PVC Pipes for Potable water supplies – specification
1665491 – 1969Laying in Situ granolithic concrete floor topping
1676006-1983Uncoated Stress relived Strand for Prestressed concrete
1686313 (Part-II) 1981Anti-Termite measures in buildings
1696313 (Part-III) 1981Anti-Terminate measures in buildings Part-III Treatment for existing buildings
1706403 – 1981Determination of bearing capacity of shallow foundations
171650 : 1991Standard Sand for Testing Cement – Specificaiton
172694 – 1990PVC Insulated cables for working voltages up to and in including 1100 volts
1737098 (Part 1) 1988Cross linked polyethylene insulated theermoplastic Sheathed cables
1747098 (Part 2) 1985Cross linked polyethylene insulated PVC Sheeted Cables
1757098 (Part-I) 1988Cross linked polyethylene insulated PVC sheathed cables.
1767272 (Part – 1) 1974Labour output constants for building work (north zone)
1777317-1993Uniaxial Jacking Test for modules of Deformation of rock.
178732 – 1989Electrical Wiring installations
179771 (Pt.1)Specification for glazed fire clay sanitary appliances: Part 1: General requirements.
180771 (Pt.-2)Specification for glazed fire clay sanitary appliances: Part 2: Specific requirements of kitchen and laboratory sink.
181783 – 1985Laying of Concrete Pipes
1827861 (Part-II) 1981Extreme weather concreting (Part – II) recommended Practice for cold weather concreting.
183800 : 2007General construction in steel
1848009 – 1976Calculation of Settlement of foundations
1858009 (Part-I) – 1976Calculation of settlements of foundations.
186801-1975Use of cold-formed light Gauge steel structural members in general building construction.
187811 – 1987Cold formed light gauge structural steel sections
1888142 – 1976Determining setting time of concrete by penetration resistance
1898142-1976Determining setting time of concrete by penetration resistance.
190822 – 1970Inspection of welds
1918519 – 1977Guide for selection of industrial safety equipment for body protection
1928520 – 1977Guide for selection of industrial safety equipment for eye, face and ear protection.
193875 (part-4) 1987Design loads (other than earthquake ) for buildings and structures (part-4) snow loads.
1949013 – 1978Method of making, Curing and determining compressive strength of accelerated-cured concrete test specimens.
195908 – 1975Fire Hydrant, Stand Post Type
1969103 – 1999Concrete Admixtures – Specification.
1979143 – 1979Determination of unconfined compressive strength of rock materials
1989537 (Part I) 1980Conduits for Electrical Installations ( General Requirements )
1999595 : 1996Metal – Arc welding of carbon and carbon manganese steels – recommendation.
200IS:2720 (part-17) 1986Methods of test for soils (part-17) Laboratory Determination of Permeability.
201IS:2911 (Part–I) Sec I)-1979Design and construction of Pile foundations (part – 1) concrete piles section : Driven Cost in situ concrete piles.
202IS:875 (Part-1) – 1987Dead loads – Unit weights of building materials and stored materials.
203SP-7: 1983 (Part-IV)National Building code of India – 1983
Con Tech & RCC Design

Interview Questions on RCC Structures Design

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  1. Characteristic Strength of Concrete –

Characteristic strength is the compressive strength of concrete tested after 28 days of 150 mm size cube. Its represented as fck and not more than 5% of the sample should fail below this value.

  • Minimum Grade of RCC –
Environmental Condition Cement Content (kg) Maximum WC Minimum Grade of Concrete
Mild 300 0.55 M20
Moderate 300 0.50 M25
Severe 320 0.45 M30
Very Severe 340 0.45 M35
Extreme 360 0.4 M40
  1. Minimum Grade of PCC –
Environmental Condition Cement Content (kg) Maximum WC Minimum Grade of Concrete
Mild 220 0.6 M20
Moderate 240 0.6 M25
Severe 250 0.5 M30
Very Severe 260 0.45 M35
Extreme 280 0.4 M40
  • Balanced (Critical), Over-Reinforced and Under-Reinforced sections –

Balanced Section – Beam sections where the concrete and the reinforcement steel both reach their allowable stress at the same time is called a balanced section. The depth of Neutral Axis xu=xumax

Over Reinforced Section – Beams where concrete reach the failure stress earlier than steel is called an over reinforced concrete. NA falls below balanced NA xu>xumax

Under –Reinforced Section – The beams where steel reaches the allowable earlier than the concrete is called under reinforced concrete. Under reinforced beam is preferable as it gives warning before failure. The actual NA is above the balanced NA xu<xumax

  • Design constants – k,j,Q –

k is the neutral axis constant –

j is the lever arm. It’s the perpendicular distance between centres of gravity of tensile and compressive forces. It is given by j = d(1-k/3)

Q is the moment of resistance constant =  

  • Minimum and Maximum Steel in Slab Beam and Column, What are the minimum and maximum spacing of rods in slab and columns ?
Member Minimum Reinf. Maximum Reinf. Spacing of Main Spacing of Stirrups
Slab 0.12% for HYSD and 0.15% for Mild Min – Ast/bd = 0.85/fy   0.04bD ie 4% of Gross cs area. Max Size of bar = 1/8 th of Total Thickness of Member  Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less.
Beam Min – Ast/bd = 0.85/fy   0.04bD ie 4% of Gross cs area. Max Size of bar = 1/8 th of Total Thickness of Member Min distance = not less than (i) The dia meter of the bar if dia are equal (ii)The dia of the larger bar if dia are unequal (iii) 5 mm more than the nominal maximum size of coarse aggregate. HOWEVER when needle vibrator is used the distance may be reduced to 2/3 of the nominal maximum size of coarse aggregate The min .vertical distance between two bars should be 15 mm. Minimum of (i) Sv = 2.175fyAsv/b (ii) 300mm (iii) 0.75d –For Vertical Stirrups d –  For inclined where, d = effective depth of the section  
Column 0.8% of gross area of col. 4 Nos bar for Rectangular Column And 6 Nos Minimum Dia – 12 mm   6% when bars are not lapped 4% when bars are lapped   Max. Distance – 300 mm  Ties – ¼ Dia of main bar. 6 mm whichever is higher. Spacing – Least lateral dimension. 16xMain Bar. 300 mm.   Helical pitch Min of – 75 mm 1/6 Dc  & Should Not be less than -3 Dia of bar forming helix. 25 mm.  
  • Minimum diameter of rod in Slab, Beam and Column –

Slab – 8 mm

Beam -12 mm

Column – 12 mm

  • Maximum size of aggregates – 40 mm.
  • What is 24 SWG wire or Black Annealed wire? What is its quantity per Quintal of steel?

Wire used for binding reinforcement. Required Quantity 0.8 kg to 1.4 kg depending upon the dia of bar.

  • Values of covers in Slabs, Beams and Columns and Column Footings. –

The cover depends upon the exposure condition of concrete for Mild Condition the values are –

Slab : 20mm

Beams :25mm

Columns : 40mm

Footings : 50mm.

  1. Point to be supervised before the casting of cement concrete in RCC structures?

Weather the reinforcements are provided as per the drawing.

Proper cover is provided or not.

Alignment conform to the proposed drawing.

Sufficient support for formwork is provided or not.

Shuttering oil is applied or not.

The surface is free from any kind of soil or debris. Etc.

  • Sizes of vibrators Oscillations, Maximum time of needle vibrators, and its range of vibration at one spot.

The size of needle vibrator vary from 40 to 100 mm in diameter. The period of vibration required vary from 30 seconds to 2 minute.

The normal radius of effect of needle vibrator is 0.50 to 1.0m. It would be preferable to immerse the vibrator into concrete at intervals of not more than 600 mm or 8 to 10 times the diameter of the needle.

The frequency of vibration varies up to 15000 rpm. A range between 3000 to 6000 rpm is suggested as a desirable minimum with an acceleration of 4g to 10g.

The concrete should be placed in layers not more than 600mm high.

  • Why Binders and Stirrups are used in columns and Beams? Where are they close and wide?

In columns ties are used to tie the main bar thus preventing them from buckling and to hold the main bar in position. The tie bar reduces the unsupported length of main bar thus acting as short column.

The stirrups are used in beams and they resist diagonal shear in beams and also hold the main bar in position.

They are placed close near the support and towards the centre the spacing may increase.

  • What is the minimum diameter of binders or lateral ties? Why longitudinal rods in columns are provided along the circumference and not at the center.

The minimum dia of binder in column is– ¼ Dia of main bar. 6 mm whichever is higher.

If the bars would be placed in centre the integrity of the concrete shape could not be maintained, crack would from due to bending stress also placement of concrete would become difficult for constructing a homogeneous column. Further he column would become ineffective in carrying eccentric load.

  • Value of lapping of roads and their ideal locations in Slabs, Beams and Columns.

For flexural tension Ld or 30d whichever is greater.

For direct tension -2Ld or 30d whichever is greater.

The lap length in compression is 24d.

The top reinforcement of the beam is lapped at center of the beam and the bottom reinforcement is lapped near the support. Basically where there is minimum bending moment the lap should be preferable placed there.

  • How turbid water can be used for concreting?

The turbidity may be removed by adding coagulant like alum also the water may be kept in tanks to reduce the turbidity by sedimentation process.

  • Why stirrups are not provided in slabs? –

The dead load are carried by the beam the beam would carry most of the shear also due to in sufficient space available the stirrups could not be placed for holding the bars in position in slab.

  • One Way and Two Way slabs. – When the length of the slab is greater equals to 2 times the width then it’s called one way slab and when the ratio is less than 2 its two way slab.

Stripping time of shuttering and Centering’s. Locations from Where Centering are to be stripped off in simply supported and cantilever structures?

Type of formwork Minimum period before striking formwork
a) Vertical formwork to columns, walls, beams             16-24 h
b) Soffit formwork to slabs (Props to be re-fixed immediately after removal of formwork)             3 days
c) Soffit formwork to beams (Props to be re-fixed immediately after removal of formwork)             7 days
d) Props to slabs:   Spanning up to 4.5 m  Spanning Over 4.5 m               7 days             14 days
e) Props to beam and arches:    Spanning upto 6 m    Spanning over 6 m               14 days             21 days

In simply supported structure the formwork should be stripped from the support towards mid span.

In Cantilever structure the formwork should be stripped from end towards support.

Where Rectangular and T-Beams are recommended? Value of bf ?

The rectangular beams are recommended along the periphery of the structure. T-Beams use concrete more economically hence require less steel.  

The value of bf =  for T beam

Con Tech & RCC Design

Interview Questions on RCC Concrete Technology and RCC Structures

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  1. What are Nominal Mix and Design Mix –

Nominal mix is the mix proportion of aggregate where no trial mix or mix design is prepared. It’s based on previous work experience.

  • What is SSD condition – Saturated Surface Dry is a condition of aggregate where the surface if the aggregate particles are dry.  Surface absorption of water is not possible in this state.
  • Capacity of Mixer Machine, Its RPM and Mixing Time – The Capacity of mixer machine varies manual machines has drum capacity of 260-500 lit (1/2 to 2 bag of cement), – 15-20 RPM or around 30 rotation.
  • What is grading of aggregate and why it is necessary – Particle size distribution of aggregate in concrete is termed as grading. Aggregates are graded to minimize the void to obtain higher density, adequate workability and better durability.
  • What happens if 12 mm stone chips are used in place of 20 mm size stone chips?

More water will be required to obtain the same degree of workability as the surface area will increase also more cement paste will require for the same strength of 20 mm aggregates.

  • What is W/C Ratio?

Water cement ratio is the ratio of weight of water to weight of cement in concrete.

Minimum and maximum value of WC ratio. Min – 0.4 Max – 0.6 as per IS 456:2000

 Slump Values –

Placing Conditions Degree of Workability Slump (mm)
Blinding concrete: Shallow sections: Pavement Using pavers: Very Low In the ‘very low’ category of workability where strict control is necessary, for example pavement quality concrete, measurement of workability by determination of compaction factor will be more suitable than slump (IS 1199) and value of compacting factor of 0.75 to 0.80 is suggested.
Mass concrete; Lightly reinforced section in slabs, beam, walls, columns: Floors; Hand placed pavements ; Canal lining; Strip footings; Low 25-75
Heavily reinforced sections in slabs, beams, walls columns Medium 50-100
Slipform work; Pumped concrete Medium 75-100
Trench fill; In-situ piling: High 100-150
Tremie concrete; Very High In the ‘very high’ category of workability, measurement of workability by determination of flow will be appropriate. (IS 9103)
  • What is curing? How it is done and why? – Curing is the process of prevention of escaping water from the concrete. Ponding, Wet Gunny Bag, Water Sprinkling and Use of water proofing chemicals called curing compounds are methods of curing.
  • What are segregation, Laitance and Bleeding?

Segregation is the separation of coarse aggregate from the concrete mix.

Laitance is the weak layer of concrete which is comprising thin layer of cement and sand particle, too much water causes bleeding and when the cement water set over the concrete laitance is formed. Also over working of concrete or improper finishing may lead to laitance.

Bleeding is the separation of cement water from the fresh concrete.

  1. Flakiness Index and Elongation Index.

Its index number representing how thin is the aggregate compared to its mean dimension. Its represented by the percentage by weight of particles whose least dimension (or thickness) is less than 3/5th of its mean dimension.

Elongation index is the percentage of the particle (by weight) whose largest dimension (length) exceeds the 9/5th of its mean dimension.