Charpy’s V notch → Toughness or impact test → Done on a building material to determine brittleness
Sectile → Property off mineral by virtue of which it can be cut with a knife
Coeff of Softening = CS fully saturated / CS dry of same material
CEMENT
Cement has cohesive & adhesive properties in the presence of water.
Cement invented → by Joseph Aspdin (1824)
John Smeaton → father of civil engineering
ρ = 1440 kg/m³
OPC G = 3.15
wt. 1 bag cement = 50kg → Water = 22.5 litres
Vol of 1 bag cement = 0.0347m³ = 34.7 litre
hydration 1gm cement = 120 Calories
Maximum cement content of ordinary Portland Cement in design mix of concrete(1m³) = 450kg/m³
Storage → Strength ↓es
C-S-H gel → Calcium-silicate-hydrate
Cement become useless if absorbed moisture > 5 % (0.05)
Strength of cement ∝ Fineness.
Fineness of cement affects only early development of strength.
Strength development of Cement ∝ Specific surface area ∝ Fineness of particles.
Particles of both OPC & fly ash are spherical in shape
Garlic Stone = iron slag + Portland Cement.
Max permissible additives in cement for construction = 2%
Voids in cement = 40%
Silicosis → Caused by dust from cement factories
Garlic stone → moulding a mix of iron slag + Portland cement
Raw material
Argillaceous : Calcareous → 1 : 3
Argillaceous (¼) → Slate, Shale & Clay, Blast furnace slag
Calcareous(¾) → Limestone(Kankar), Chalk, Marl, Compound of calcium & magnesium
Most commonly used → Limestone
Dry process is considered to be economical bcz in the wet process longer kilns are used which consume more fuel
Rotary kiln speed = 1 - 3 rpm
Kiln temperature → Wet = 1400 -1600℃, Dry = 1300 -1450℃, Burnt at 1400℃
Chemical composition
Low alkali cement < 0.6 %
Alkali content = %Na2O x (61/61) + %K2O x (61/94) equivalent to Na2O
Green colour cement → Chromium dioxide
Maximum permissible additives in cement for construction = 2% as per IS-Code
Bogue's Compound
C3S + C2S = 70 - 80%
Cementing property/strength → C3S > C2S > C3A > C4AF (ABCF)
Rate of hydration → C4AF > C3A > C3S > C2S (FACB)
Order of set → C3A > C4AF > C3S > C2S (AFCB)
Heat of Hydration → C3A > C3S > C4AF >C2S (ACFB) ←Rate of Heat evolution
Flash Set
Stiffening of cement paste without strength development with heat evolution
Caused by C3A & Alkalies → Prevent by use of Gypsum
False set → Abnormal and Premature hardening
Gypsum (Calcium Sulphate CaSO4)
≤ 2.5 - 3 % → Reduce flash setting
Usually mixed with clinker at the end of grinding the clinker into powder → Clinkers are calcined products
Water Requirement for hydratⁿ
Bound water = 23% by wt. of cement
Gel water = 15% by wt. of cement
Total minimum = 38% → For complete chemical reaction
OPC CS (OPC 33, 43, 53)
Grade A = 30 - 35 Mpa
Grade B = 35 -40
Grade C = 40 - 45 ... And so on
Test for cement
Lime saturation factor
LSF = 0.66 - 1.02
LSF = Lime% / (Al + iron oxide + silica)%
Physical tests
To determine grade of cement → C:S = 1:3 → Cement = 55gm & Ennore sand = 185gm
Heat of Hydration → Measured by Calorimeter
Specific gravity → le-chatelier flask (OPC G = 3.15)
Specific surface → By turbidimeter
1) Fineness Test
Fineness of cement → increase rate of strength development, leads to higher shrinkage, Affects only early development of strength
2) Consistency Test
% of water required for preparing cement paste (consistent paste)
Normal consistency = 30%
For Normal consistency Penetration → Bottom = 5-7mm, Top = 33-35mm
By Vicat's apparatus → Solid Circular, D = 10mm, L = 50 & 40mm
3) Setting time Test
Temp = 27 ± 2 °C , Relative Humidity = 60 - 70 %
Penetration = 5 - 7mm (33 - 35 mm)
300gm cement + 0.85P water → P = Std consistency
Common sugar Retards the setting of concrete
Before testing setting time one should test for consistency
Cement stored in warm rooms is set more quickly than stored in Cold places
Determination of initial & final setting time is based on change in penetration resistance over time due to hydration
initial setting time
By Vicat’s apparatus → Square needle , D = 1mm, L = 50 & 40mm
Cement remain in plastic State
Lime pozzolana → Ti = 2 hrs
Final setting time
By Vicats apparatus → Annular collar, D = 5mm, L = 50 & 40mm
4) Soundness Test
Le chatelier's method
Free lime only
100gm cement + 0.78P water
Ht = dia = 30mm, Split ≤ 0.5 mm & L = 165mm
Result in Expansion (mm) → OPC,RHC,LHPC ≤ 10mm & HAC,SSPC ≤ 5mm
Increase in the distance b/w pointers = 5 - 10 mm
Autoclave test
Determine expansion → Both lime & magnesia
Result in percentage % expansion → For all type of cement expansion ≤ 0.8%
5) Compressive strength
By CTM or UTM → To check Quality of cement
Cube size = 70.6mm = 7.05cm , Cube surface Area = 50mm²
Concrete cube size = 150 x 150 mm
Cement (185gm) + Ennore sand (555gm) → C:S = 1:3
W/C = 0.4 & water = (P/4 + 3.5) %
Humidity = 90%
6) Tensile Strength
By briquette test or split tensile strength test
C:S = 1:3, (P/5 + 2.5)%
Generally used for RHC
TYPES & USE OF CEMENT
High early strength of cement → Fine grinding and burning at higher temperature
Hydrated cement paste → Principle strength due to Dicalcium silicate
Black cement → Lime + Rice husk ash
Blast furnace slag cement → Marine work, Underwater construction, Calcium oxide(CaO) = 45%, Silica(SiO) = 35%
Calcium Chloride Cement → Deliquescent
Expansive Cement → Used in repair work for opened up joints, expands while hardening
Hydrophobic cement → Grinding clinkers with oleic acid, Waterlogged area, humid region
Low heat cement → Low % of C3A, C3S & High % of C2S, Abutment, Dam
LHPC → Heat of hydration → 7day = 65 cal/g & 28day ≤ 75cal/g
Portland pozzolana cement (IS 1489) → lining of deep tube wells, Sea water construction, Pozzolanic material = 25 - 35 %, require more curing time wrt OPC
Portland Slag Cement → Slag = 40 - 70%
Refractory cement → Rich in Aluminium (Bauxite)
Sulphate Resisting cement → C3A < 5%, Coastal protection work, Canal lining, Culvert, Retaining wall
Super Sulphated cement → Extremely resistance to chemical attack
Slow Setting Cement → Higher % of C2S & Gypsum
Portland/Ordinary/Normal setting cement
3 Grades → OPC 33,43,53 grade → All 3 in IS 269
Old → 33(IS-269), 43(IS-8112) & 53(IS-12269)
3 days CS → OPC 33 > 16 Mpa, 43 > 21 Mpa, 53 > 27 Mpa
Quick setting cement
Under water constⁿ & Grouting,
Produced by adding Aluminium Sulphate in powder form
Rapid hardening cement (RHC) (IS 8041)
Higher % of C3S & finer grinding of cement, It has high Lime content which results in shortening the final setting time
High early strength required
Pavements & Repairing of roads → Not suitable for RCC Structure.
residue = 5%, Ti = 30 min, Tf = 10hrs.
White Cement
Least % of iron oxide
Composition wrt Cement content and W/C ratio
Commercial name → Colocrete, Silvicrete, Snowcem
White colour → Limestone & china clay free from metal oxides
Hunter scale → Whiteness of white cement
Air Entrainment Portland Cement
Resistance to sulphate attack, resistance to freezing & thawing
↓es Shrinkage & Crack formation
High Alumina Cement
Produced by fusing Limestone & Bauxite Together
Should not be used with any Admixture
Highest CS after 3 days
Pozzolanic material
Composed of microscopic & Amorphous silica
Rich in silica & alumina
Finally divided pozzolana reacts with lime and produce Calcium silicate
Reduce cost & permeability of concrete
↑es → initial setting time, durability, ultimate strength, bond strength, E of concrete, workability, resistance to cracking & chemical attack, resistance to sulphate attack.
↓es → Early strength, HOH, permeability, shrinkage, segregation, bleeding, chemical attack.
ex. Surkhi, fly-ash, Volcanic ash
Use → Dam, mass str, abutment, lining of deep tube wells, marine work
Finely divided pozzolana reacts with lime producing Calcium silicate
Fly ash
Constituent → Silica, Aluminium oxide, Ferrous oxide
A byproduct of Coal, Residue generated from Thermal power plant
wrt cement content & W/C ratio
Storage of Cement
1 bag require 0.3m² space → Each stack ≤ 10 bags
CONCRETE
Concrete is a Visco-elastic material → Under instantaneous load it behaves like elastic
Specific Heat = 840 - 1170 joule/kg/°C
Std. Size of wooden box in preparing cement concrete to measure sand aggregate = 35 x 25 x 40 cm.
Due to bulking, less quantity of concrete per bag of cement will be produced.
Behaviour of concrete under instantaneous load is Elastic.
Voids in concrete → Water void, Air void, Gel void.
1% void → Strength reduced by 5%
Carbonation →reduction of pH value in concrete.
Coeff of softening = CS of fully sat material/dry material.
Fibres → improve Tensile strength of concrete
Min t of lean concrete layer below foundation = 100mm.
Method of Underwater concreting → Pumping, Hydro valve, Toggle bags, Bagged concrete, Termie, Caissons method .etc
OPC should be tested before use if storage is > 03 months
IS 1199:1959 → Sampling & analysis of concrete
Rate of loading = 14N/mm² per minute → To check CS of Concrete or Brick
Carbonation → Reduction of pH value in concrete
Manufacturing Stage
BMTPCFC
Loss of workability → Setting → Hardening
1. Batching
Accuracy → Cement = ± 2%, Agg, Admixture, & Water = ± 3%
Types = 02
Vol Batching→ Small work, Wooden box = 35 x 25 x 40 cm
Weight Batching→ imp works
Cement is measured by wt. irrespective of the Batching method
2.Mixing
t ≤ 2min & Hand mix ≤ 3min → 20 no. of revolution are sufficient
10% extra cement to be added in case of Hand mixing
Concrete mixer → Specified by vol of mixing drum or vol of concrete.
Agg > 75mm → Cannot use Non-tilting mix
IS : 1791 → Specification of batch type concrete mixer
3. Transportation
By pumps → tunnel lining
4. Placing
Free fall ≤ 1.5m to avoid segregation
Low temperature during laying increase Strength of concrete
Tolerance d > 200mm = ±20 mm.
Consolidation of concrete should proceed immediately after placing
5. Compaction
internal Needle vibrator: D = 25-75mm & L = 25 - 90cm
Mechanical vibrator Slump ≤ 5mm
Screed or Surface Vibrators: road slabs, floor slabs, floor slabs.
Formwork or external vibrator: columns, thin walls, casting of precast units.
t for M + T + P + C ≤ ti (30min)
6.Finishing = SFT
Screeding: excess concrete to bring the top surface upto proper Grade , removes humos & hollow
Floating: irregularities on surface by wooden float
Trowelling: very smooth finish & final operatⁿ of finishing
Slump > 50 mm Results Difficulty in Finishing of Concrete Surface.
Surface vibrator →Used to finish concrete surfaces such as bridge floors, road slabs, station platforms etc.
7. Curing
Relative humidity = 90% , T = 27 ± 2°C, 24 ± ½ hrs
Curing increases Compressive strength
RHC = 3 - 7 day, OPC = 7day
Concrete exposed to dry conditions = 10 days
Mineral admixture & blended cement used minimum curing period = 14 days
Steam curing → Not suitable for HAC, ↑es initial strength & ↓es 28 day CS & ↓es τ, Precast structure
Membrane curing → Hilly areas, Indian climate, Prevent evaporation of water
Ponding → Horizontal surface ex. Floors, roofs, slabs, roads
Hydration process
Loss of workability → Setting → Hardening
Maturity
M = Time x ∆Temp (°C hours or °C days)
Datum Temp = -11°C
Theoretical strength
Theoretical Strength = 240 x (Gel-Space ratio)³
Gel-space ratio = 0.657C / (0.319C + W)
Water
Free from injuries material of oils, acid,alkalies,salt, sugar, organic matter
Water require per bag of cement = 0.4
2% oil in water → Strength ↓es by 20%
Sea water → Strength ↓es by 10 - 20%
W/C = Water to cement by weight → Expressed based on weight of materials
Expressed in vol of water required per 50kg bag of cement
For 50 kg of cement water required → 22.5 litres
Lower w/c ratio → More density, small creep & shrinkage, more bond
Grade of Concrete increased → W/C ratio is Decreased
Free water cement = water content/ water cement Ratio
For given aggregate ratio ↑es WC ratio →↑es Shrinkage.
Lead nitrate has the highest destructive effect for concrete if mixed with water.
Min Quantity of water for 1st Batch
(W/C)P = 0.1P + 0.3Y + 0.1Z
P = wt of cement, Y = fine agg or Sand, Z = Coarse Aggregate
Abrams water-cement law (1919)
By Duff Abrams → Concrete should be fully compacted
Amount of water = (30% Cement + 5% FA) W/C Ratio
The Concrete Should be fully Compacted.
10% extra water → Strength ↓es by 15%
30% extra water → Strength ↓es by 50%
Ferrocement w/c = 0.4 - 0.45
A concrete design mix with a low water/cement ratio and also using larger aggregates results in Gain in concrete compressive strength
Factor affecting Strength of concrete
Strength primarily → Depends on water cement ratio.
S ∝ Rate of loading
S ∝ Cement-Aggregate
S ∝ degree of compaction
S ∝ size of aggregate
S ∝ agg gradation
S ∝ 1/size of specimen
S ∝ 1/age
S ∝ 1/moisture in specimen
S ∝ 1/air voids
S ∝ 1/Humidity
Strength → Well graded & Angular shape
Workability→ Smooth & bigger size agg
Durability ∝ Cement-Aggregate ratio
1 % entrapped air → Average quality of concrete mix
WORKABILITY
Measure of Consistency
Flow table > slump > CFT > Vee Bee
W ∝ Cement content
W ∝ Size of agg
W ∝ Water content
W ∝ Grading
W ∝ 1/Time of transit
W → Round >
Aggregate ratio = 2 → the workability is independent of the aggregate cement ratio
1. Slump test
in terms of mm, Lab or field test for high workability, Measure plasticity (consistency)
Facilities controlling the W/C ratio
4 layer & 25 strokes per layer
Top D = 10cm, bottom D = 20cm & ht. = 30cm.
Change of water content for 2.5cm slump = 3% (1cm = 1.2%)
Slimp > 50 mm → Difficulty in finishing of concrete surface
2.Compaction factor test
in terms of internal energy, Lower w/c ratio, Pavement concrete
Concrete is dropped from a height → Meas Consistency/workability
CF ∝ Slump ∝ High workability
3.Vee- bee consistometer
in time(seconds), Suitable for slump < 50mm, Low workability
High value means low workability & vice-versa
For fibre reinforced concrete
4. Flow table test
Time check, Very high workability, Also to check Proneness to segregation, Workability of tremie concrete
Flow % = (Spread dia(cm) - 25 ) / 25
Range 0 - 150
Mould = 2 layers → Each layer tamped 25 times
Flow table raised at the height of 12.5 mm & dropped
Repeated for 15 times in 15 seconds
5. Kelly ball Apparatus
Field Test → Consistency of plastic concrete
Recommended Slump value
Power driven < 25mm
Hand driven = 25 - 50 mm
Mechanical vibrator ≤ 50 mm
Normal vibrator = 100mm
Pavements or concrete roads = 20 - 50mm
Columns & slabs = 40 - 50mm
Unreinforced footing = 25 -75mm
Hand placed Pavement quality concrete = 25 - 75 mm
Columns = 50 - 150mm
Normal RCC work = 80 - 150 mm
Air content measure in concrete
Gravimetric method
Pressure method
Volumetric method
Classification of concrete based on density (ρ)
i. Lightweight/Cellular concrete
ρ = 300 - 1800 kg/m³
Load bearing wall
Precast floor & roof panels
Partition wall
insulating material to exterior wall
ii. Dense wt.
ρ = 1800-2500kg/m³
iii. Super heavy wt.
ρ > 2500kg/m³
Types of concrete
SRC →Sulphate Resistant Concrete
RMC →Ready mix concrete
Vacuum Concrete → Entrained air & excess water are removed after placing it in position, ↑es CS, TS, Durability, ↓es shrinkage, Permeability
Aerated Concrete → floor constⁿ, fire proofing, Produced by addition of Aluminium powder
Asphalt Concrete (Bitumen Concrete) → FA + CA + filler material & Bitumen, high quality Pavement
Polymer Concrete (Polymer Portland Cement Concrete) → Sewage disposal work, Corrosion protection
Defects of Concrete
Order → Shrinkage→ Flexure→ settlement→ corrosion
Blow holes → improper design of shuttering
Bleeding → Water comes to the surface, rich mixes < lean mix, ↓es strength, formation of pores inside
Bleeding ↓es by → increasing fineness of cement, using admixture (calcium chloride), adding pozzolana
Cracks → Width = 0.1 - 0.3,
Crazing → Network of fine random cracks, hair like cracks usually in an irregular pattern.
Efflorescence → fluffy white patches, due to salty water generally
Honeycombing → Badly mixed Cement Concrete, excess vibration of green concrete, inadequate Compaction, improper placement
Laitance → When water comes with cement particles (cement & water slurry) to the surface.
Leaching: disolutⁿ of some concrete compound in a liquid, it is a chemical reactⁿ, concrete is attacked by a solⁿ of acid & certain salts.
Segregation → Separation of mtrls due to diff G. or Breaking up of cohesion, Surface scaling, honeycombing, porous layer
Risk of segregation is more for wetter mix and larger proportion of maximum size aggregate and coarser grading
Non Destructive Test
Quality of hardened concrete
i. Rebound Hammer test (Schimidth Hammer test)
Gives compressive strength of hardened concrete → Compares the dynamic modulus of elasticity of samples of concrete
Represent hardness of surface
ii. Ultrasonic Pulse Velocity Test
compares the dynamic modulus of elasticity of concrete samples
Hardness
Vs = √(E/ρ)
Vs ∝ Strength
Good Quality concrete > 3.5 km/sec
iii.Maturity test
iv. Pull - out test
v. Penetration test
Core test → CS of in situ concrete, It is Partially Destructive for Beams/ Columns
Admixture
Water reducing admixture → Lignosulphonate
1. Chemical Admixture
Added at time of mixing of concrete
Calcium carbide → ↑es Shrinkage, ↓es Setting time
Types of Chemical Admixture
Plasticizer
↑es workability , ↑es strength → ↓es water or w/c ratio
ex. Hydroxylated carboxylic acid
Super plasticizer
High range water reducers
Disperse the particles, remove air bubbles & to retard setting
Ex. Sulphonated melamine formaldehyde
↑es workability, ↑es early age strength → ↓es quantity of mixing water, ↓es quantity of cement
Accelerator
Rapid setting, ↑es shrinkage, ↑es Rate of hydration
Ex. Calcium chloride, Silicate, Aluminium sulphate, CaCl2, NaCl, Na2SO4
Retarders
Ex. Hydrated Calcium sulphate, Sugar, Gypsum(CaSO4.2H2O), CaSO4
Air Entrainers
Increasing the workability of concrete at the same unit water content
impart resistance against freezing & thawing
Ex. Zinc & Al Powder, Vegetable oils, Fats, Neutralised vinsol resin
Air entraining agent is commonly mixed in concrete to control expansion
2. Mineral Admixture
Added after grinding of cement clinker
Ex. Pozzolana, Silica fumes, rice husk, fly ash & blast furnace slag
Form work
AGGREGATE
A inner or filler material
Bulky density of Agg = Net wt of agg (Kg)/ Vol of Container(ltr)
70 - 80% in concrete
Rounded have least void.
For best workability → Smooth & bigger size
For good Strength → Well graded & angular
Most chemically active concrete aggregate → From igneous rock
Limestone → Exhibits alkali-aggregate reaction should be avoided in concrete
Function of Sand in mortar
Providing strength
Reducing consumption of cement
Reducing shrinkage
Size of aggregate
Cyclopean > 75mm
Coarse = 80 - 4.75mm
Fine = 4.75mm - 0.075mm
Types of aggregate
Strength → Angular > Crushed > Cubical > Rounded > flaky/irregular
i. Angular aggregate
max void(40%) → high strength
very good bond & high strength.
angular are superior to rounded
ii. Rounded aggregate
Min surface area/volume → Minimum cement paste require
Avoid for high strength concrete & for pavement subjected to Tension
min void ratio (32%)→ High workability
w/c = 0.65
Ex. River/Seashore gravel
iii. Flaky aggregate
Lateral dimension < 0.6 (3/5) x mean dimension
iv. Elongated:
Length = 1.8 (9/5) x mean dimension
Flakiness & Elongation test is not applicable for size < 6.3mm
Grading of aggregate
Necessary to Achieve Reduction in voids concrete mix
Uniformly or Poorly graded → Vertical line curve
Gap graded → Horizontal Curve line
Well graded → S-shaped, Curve line diagonally
IS 383 : 1970 → Size of aggregate, particle shape, colour, surface texture
IS 383 : 2016 → Grading of fine Aggregate → in 4 Zones (Zone I, II, III, IV
Percentage passing of Fine aggregate
Nominal size of Aggregate used in concrete
Max size of coarse aggregate ≤ 1/4 of thickness of member
Most of work, RCC construction = 20mm
Thin slab = 10mm
Beam of c/s 100x200mm ≤ 25mm
Base coarse in ground floor ≤ 40 mm
Dam, footing > 40mm
Fineness modulus
index which gives mean size of agg used in a mix
% of FA = (CA - MA) / (MA - FA) → Use alligation and mix formula
Fine Sand = 2.2 - 2.6
Medium Sand = 2.6 - 2.9
Coarse Sand = 2.9 - 3.2
Fine Agg = 2.0 - 3.5
All in Aggregate = 3.5 - 6.5
Coarse Agg = 5.5 - 8.0
FM = (cumulative % retained)/100
FM ∝ Particle size
Bulking of Sand
Increase in vol of sand caused by the films of water (Surface Moisture)
Due to Surface tension
Bulking ∝ 1/particle size
Max bulking = 40 % of volume
Max bulking at 4.6 % water content
MC > 10 % → Decrease in Bulking
Bulking factor = Vol. of moist sand / Vol. of dry sand
In volume batching we consider the bulking of sand effect
If bulking of sand is not taken into account → Less quantity of concrete per bag of cement will be produced
Agg Dust
Low workability + Coarse grading = 5% of Agg
Low workability + Fine grading = 10%
High workability + Fine grading = 20%
TIMBER
Properties of timber
G = 1.54 & Orthotropic
TS = 3 x CS
Sound conductivity = (3 to 4) x in air
E = (0.5 - 1) x 10⁴ N/mm²
E longitudinal/E transverse = 1 to 2.
Swelling along length of fibres = 0.1 - 0.8%
Naturally Anisotropic
Screws for wood work are specified by length.
Refractory timber → deodar
Most valuable → chir
Timber max strength = parallel to grain
Min strength = perpendicular to grain
Tree fall = summer(hill) & winter(plane)
most valuable timber may obtain from TEAK.
max Resistance against red ants = Teak.
Max strength →Along or parallel to grain.
Weight → at 12% moisture content
Natural heartwood timber avg life ≥ 120 months = 10 years.
G specimen size = 5x5x15cm or 2x2x6 cm (rectangular)
Shear strength of timber depends on Lignin & fibres.
Types of Timber
1. Endogenous
Grow inward.
Ex. Bamboo, Cane, Palm.
2. Exogenous
Grow outwards
Ex. Deodar, Chir, Pine, Oak, Teak, Shisham, Sal
Subtypes of Exogenous
i. Conifers / Softwood
Light clr, Fast growth, Needle shaped leaves, light weight, Distinct Annual rings, resinous str & split easily.
Ex. Deodar, Chir, Pine
ii. Deciduous / Hardwood
Dark clr,slow growth,broad shape leaves
Ex. Oak, Teak, Shisham, Sal
Used in engineering applications.
Classification of Timber
1. Position
Standing Timber : living tree
Rough Timber : part of felled tree
Lumber : logs of Timber sawn into planks ,post.
2. Modulus of elasticity
Grade A > 12.5 KN/mm²
Grade B = 9.8 - 12.5
Grade C = 5.6 - 9.8Kn/mm²
3. Availability
Grade X = 1415 m³/year
Grade Y = 355 - 1415 m³/year
Grade Z < 355 m³/year
4. Durability
High durability: life > 120 months
Moderate durability: 60 - 120 months
Low durability: < 60 months
5. Humidity for air Seasoning
Zone I < 40 % Humidity
Zone II < 40 - 50 %
Zone III < 50 -67 %
Zone IV > 67 %
Structure of Timber
PHASCIO(M)
Sapwood → Youngest layer of timber
Cambium layer → Thin layer of fresh sap, contains living cells
Sawing of Timber
Ordinary: Quick & Most economical
Rift/Radial sawing: Strongest but more wastage & preferred over all.
Tangential sawing : Gives minimum strength timber
Quarter Sawing :
DEFECTS
i. Conversion defects:
Wane: Presence of original rounded surface on the mfd timber.
Torn Grain : impression of fallen tool
Chip mark : By chips on finished surface of timber
Diagonal grain : improper Sawing
ii. Due to Fungi.
Sap stain: Fungi feeds on cell content of sap wood results in wood colour loss
Dry rot: Lack of ventilation & sunlight , reduce in form of powder, Shrinks the timber
Wet rot : alternative dry & wet conditions.
Brown rot: Decomposes cellulose and associated pentosans, leaving the lignin in unaltered state, the resultant mass of decayed wood of varying shades of brown.
Dry rot & wet rot are diseases of timber.
iii. Natural forces
Major natural forces are Abnormal growth & Rupture of tissue.
Burls :
Rind galls: abnormal growth or curved swelling on the body of the tree.
Knots : bases of branches which are broken or cut-off from trees, soft -ve growth under damp conditions.
Foxiness : red/yellow/reddish brown stains around the pith due to lack of ventilation or over maturity of tree
Shakes: longitudinal separation in wood
Heart, star, ring, radial,cup.
iv. Seasoning.
Bow:
Cup:
Twist:
warp:
Honeycombing: internal cracking ( Separation of fibres ) due to drying.
Preservation of Timber
↑es life, Durability & Prevent against fungi
Solignum salt, Chemical salt & Creosote
Penetration = 6 - 25mm
Effectiveness → Pressure > Hot & cold > Dipping > Spraying > Brushing.
DDT (Dichloro-diphenyl trichloro-ethene) is applied for Prevention insect
i. AsCu treatment:
Developed by FRI dehradun.
Solignum paints: preserve the timber from white Ants
against Termite attack.
ii. Bethal process/ Creosote oil:
Application of creosote oil on timber, obtained by distillation of tar.
Creosote oil is derived from wood or coal
Treatment
a) Charring: Depth of 15mm @ 30min.
b)
FIRE RESISTANCE
i. Application of special chemical
Two coats of borax or sodium arsenate with strength 2%.
Antipyrine containing Ammonium or boric or phosphoric acid are considered best.
ii. Sir's Abel's process
Surface painted by a weak solution of sodium silicate.
Soaking in ammonium sulphate.
SEASONING
↓es weight, Shrinkage & warping , Split & decay
↑es strength, durability & stiffness.
Make timber burn readily as a fuel & suitable for painting.
imperfect seasoning → honeycombing ,bow defects
IS 1141-1958 →Classification of timber for seasoning purpose
i. Natural seasoning
Air, max 15%.
ii. Artificial Seasoning
Boiling, chemical, electrical,kiln & water seasoning.
Boiling → timber becomes brittle & easy to break.
Electric seasoning →Reduces Strength
Market Form of Timber
Plank → Parallel side & t < 50mm & Width > 50mm
Batten →Width = thickness < 50mm
Log → Trunk of tree without branches
Fibre board → Used for insulation
Board → t < 50mm, breadth > 150 mm.
Veneers →Thin sheets of superior quality, t = 0.4 - 6 mm, Obtained by rotating a log of wood against sharp knife of rotary cutter
Scantling → Breadth & t 50 - 200mm.
Bolt → Short log ≤ 1.25 m.
Plywood
Good & same strength along & across grain, greater impact resistance.
Arches & mfd of veneers
P = 7-14kg/cm²(100 - 150N/cm²)
Temp = 100 - 130°C,
Plywood is specified by no. of Layers.
min piles = 3.
Assembled product of veneers & adhesives.
Made from Common timber.
Note:
Strength → Battens > lamin > plywood > veneer.
Max deflection for timber beam = Span/360.
Use of Timber
Babul → Agriculture instrument
Bamboo → Scaffolding
Mulberry → Sports goods
Sheesham → Wooden mould
Kail → Railway sleeper.
Jack → Musical instruments
Deodar → Railway Sleepers
Teak →Boat.
Resistance to white Ant → Sheesham > Teak.
BRICK
IS 6165-1971: dim for special shape of clay
avg wt. Of one brick = 3kg
no in 1m³ = 500 bricks
min. t of brick wall = 10cm
ρ common burnt clay bricks = 1600 - 1920 kg/m³ → IS:875(Part-I) - 1987
wt 1m³ = 1800kg
Unit wt. Of brick work = 19.20 kN/m³
broken brick ρ = 14.2 x 10³ N/m³
frog = 10 x 4 x 1cm³
IS:6165-1971 → Dimension for special shape of clay bricks.
permissible or minimum compressive strength = 2 - 3.5 N/mm²
mechanical properties → CS ,TS, fire resistant, MOR
Modulus of rupture = 2.5
Prestressed brick has Two frogs & hand mould has only one
Terracotta (baked clay): ornamental work
Spall: stone chips or broken bricks.
Stone wares : refractory clays mix with stone & crushed pottery
Charpy’s V notch test → Brittleness of building materials
MARDINI → mfd of Mud Blocks
Shrinkage due to moisture movement → Concrete block > Bricks
Modular Bricks
Std or Actual size → 19 x 9 x 9cm
Nominal size → 20 x 10 x 10 cm
Non Modular or Traditional Brick
Std or Actual size = 22.9 x 11.2 x 7 cm³
Nominal = 22.9 x 11.4 x 7.6 cm³
Brick tile
Std or actual size = 19 x 9 x 5cm³
Nominal = 20 x 10 x 5cm³
Brick wall
1/2 brick wall = 10 cm = 4.5"
1 brick wall = 20 cm = 9" → Load bearing wall
2Brick wall = 40 cm = 13.5"
1inch = 2.54cm
Constitute of Brick [SAILM]
Silica = (50-60%) → Clay & silt
Provide Strength, Hardness, Durability, Retain shape, impart uniform shape
Prevent Cracking, Shrinkage, & Warping.
Excess → Cohesion destroy, brittle, weak
Alumina = 20-30% → Clay
Plasticity to brick so it can be moulded.
excess: shrinkage, warping, cracks on drying
iron oxide = 5-6%
Red colour, help lime to fuse
excess: make brick dark blue & blackish
deficiency: bricks become yellowish.
Lime ≤ 5%
Lowers fusing point, Prevent shrinkage of raw brick
Excess → brick melt or loss shape & colour red to yellow, melt & distort during burning.
Magnesia < 1%
Give yellow tint , ↓shrinkage, ↓warping
Causes the clay to soften and reduces warping
Excess → decay of bricks
Classification
BIS → Classified the common burnt clay on the bases of compressive strength
Strength base classification → IS: 3102
1 N/mm² = 10 kg/cm²
Class 10 → CS ≥ 10 Mpa ( IS 1077)
Grade/Class AA
CS > 14 MPa
1st Class Brick (Grade or Class A)
CS ≥ 10.5N/mm²
water absorption ≤ 20% of dry wt of brick
table moulded, recommended for painting, exposed face work in str
load bearing masonry
2nd Class Brick (Grade B)
CS ≥ 7N/mm²
water absorption ≤ 22%
3rd Class Brick (Grade C)
CS ≥ 5.5N/mm²
water absorption ≤ 25%
Used in temporary brick masonry
4th class Brick (Jhamma or over burnt)
Over burnt, badly distorted
Jhama bricks → Over burnt with irregular shape
Used in brick ballast, lime concrete foundation, road metals
Other types
Bullnose brick → Used in pillar, decoration purpose, rounding of sharp corner
Hollow / Cavity / Cellular brick → Light in weight, ↓es transmission of Heat,Sound,Dampness
Fire bricks → Are made from Fire clay.
Under burnt bricks → Soft & light colour, Crumble even on light crushing
Perforated bricks → CS ≤ 7N/mm²(7MN/m²), Used in Reinforced brick work
Pressed bricks → Used for decorative works
Refractory brick
Highly resistant to corrosion and temperature (upto 1709°C)
Kiln lining, lining of furnaces
Basic RB → Dolomite, Magnesite, Bauxite
min avg CS > 3.5Mpa
Water absorption = 4 - 10%
Heavy duty burnt clay bricks (Engineering bricks)
CS > 40N/mm²
Water absorption ≤ 10%
Heavy duty burnt clay brick bulk density ≥ 2.5g/cm³
Bridge, industrial foundations, multistory buildings
Efflorescence = 0 → No efflorescence allowed
Burnt clay bricks 3.5 < CS < 40 N/mm²
BIS classified the common burnt clay bricks on the basis of Compressive Strength
Manufacturing OF BRICK
Additives in manufacturing of bricks are Basalt stone dust, Sandy loam & Rice husk ash.
Preparation of clay → Moulding → Drying → Burning
Preparation of clay
Pug mill → Preparation of clay(kneading, Tempering)
Kneading is mixing clay, water, & other ingredients to make bricks, it is temporary process
Unsoiling(20cm) → Digging(60-120cm) → Cleaning → weathering → Blending → Tempering(in Pug mill)
Blending → Clay is made loose and any ingredient to be added to it is spread out on top and turned up and down in a vertical direction
Moulding
Ground, Table & machine moulding
Wooden moulds → Shisham
Size of mould 8 - 12 % more than brick size
Hand mould bricks → CS = 60000 & TS = 2000 KN/m²,
Table mould bricks → Pallet board is used, Stock bricks
Ground moulded bricks → irregular in dimension
Machine mould bricks → Wire-cut bricks
Tolerance in the width of mould of a class-I brick = ± 3 mm
Drying
Should be dried in air for 3 - 8 days but not in sun
Moisture is reduced up to 2 %
Strength gain by drying of bricks = 15 - 25 Kg/cm^2
Hacking: process of drying bricks in an open atmosphere
Burning
Imparts strength & hardness
Temp = 900 - 1200°C
Clamp burning θ = 15°
Kiln burning → Time complete burn = 24 hrs
Avg. Outturn 1st class Brick → Clamp burning = 60% , Kiln burning = 80 - 90%
At temp 700 - 1000°C → chemical changes in Brick
For Glazing clay products Sodium chloride should be thrown into the kiln at 1000 - 1300°C temperature
a) intermittent kiln
b) Continuous
Bull's trench k → most popular bcz of low initial cost.
Hoffman's k → Circular, above ground, also operated in rainy season
Tunnel k →
Testing of Bricks
Dimension Test
20 bricks of std size (19 x 9 x 9 cm) selected randomly → Tolerance = ± 80, ±40, ± 40mm → For length, width and height respectively
Tolerance in length = ± 6 mm & width = ± 3mm
Compressive Strength (IS : 3495 Part-I)
Minimum 6 bricks required
CS Variation = 15% of
CS > 12.5 Mpa → Slight eff....
CS < 12.5 Mpa → Moderate
Loading rate = 14N/mm² = 140 Kg/cm² per minute
Class 25 bricks → CS = 25N/mm² = 250kgf/cm²
Water absorption test (IS : 3495 Part-II)
5 bricks require → immerse in water for 16hr
Good brick < 20%
Burnt clay perforated brick ≤ 15%
Up-to class 12.5 ≤ 20% of its dry weight
for Class (> 12.5) ≤ 15%
Class 20,25,30 & burnt clay perforated brick ≤ 15%
Warpage Test (IS : 3495 Part-IV)
10 Bricks required
Hardness Test
Scratch by nail/finger
Efflorescence Test (IS : 3495 Part-III)
Patches of white deposit
Nil = 0%
Slight eff ≤ 10%
moderate = 10-50%
Heavy ≥ 50%
Serious efflorescence = On Surface
Presence of soluble salt Test
immerse in water for 24hrs.
cause efflorescence on surface of brick
absence of grey/white deposit = absence of salt
Soundness Test
two bricks are taken & stuck with each other brick shouldn't break & a clear ringing sound should produce.
Structure Test
should be homogeneous,compact & free from any defects such as holes.
Harmful ingredients in brick earth
Lime: cause unsoundness, in excess cause of brick yellow colour,
Alkalies (soda-potas): efflorescence
Iron pyrites:
Pebbles,Gravels & Grits: non uniform mixing of clay
Organic matters: assists in burning→become porous→↓es strength
Defects in Bricks
Over burning: loose shape
Efflorescence: Soluble salt(soda & potas), Sulphate of calcium, Alkalies,high PH of water, low silica content
Bloating: spongy swollen mass over bricks surface due to excess of carbonaceous & sulphur matter i.e. swelling
Blister: due to air imprisoned during moulding
Chuffs: deformation of shape of brick caused by rain water on hot bricks
Under burning: light clr, crumble easily & soft.
Lamination: entrapped air in voids of clay
Black core:
Test for Tiles:
Breaking strength test, impact test, transverse strength test, water absorption test
IS:15622-2006 → Vitrified tiles and ceramic tiles testing
BRICK MASONRY
Course → Horizontal layer
Bricks are soaked in water before using in brick masonry for preventing depletion of moisture from mortar and to remove air voids
L = 2B + t → L, B = Length, Width of Brick, t = thickness of mortar
Mortar strength should match brick strength
Types of Bond:
1. Stretcher bond:
stretcher on face of wall
length of stretcher with mortar = 20cm
length stretcher/header = 20cm/10cm = 2
vertical joint in Sb = ½ header bond
2.Header bond:
header on face of wall
length of header with mortar = 10cm
3. English Bond:
alternative course/layer of Header & Stretcher
stronger than Flemish bond
Dutch bond :
Modification of English bond i.e, every stretcher course start with three quarter brick
4. Flemish Bond:
each course/layer has alternative Header & stretcher
economical & better in appearance
Brick Closer
King → Angle cut half of head to ½ of Stretcher
Queen → Half & Quarter → Cut half long & then Lateral
Bevelled closer → Angle half of header to edge, kone se width ke half mai
Half bat → Cut half from stretcher
Mitred → Kone se length ke half mai
Squint closer → Angle ≠ 90°
Cent → Triangular cut on one side
MORTAR
Plastic Asphalt → Mix of Cement & Asphalt
Binding agent → Either cement of lime
Lime Mortar
Doesn't set quickly
Generally made with hydraulic lime(Calcium oxide) sometimes with fat lime
Ordinary lime mortar → Cured by Air, Min curing time = 7day
Mixing in Pan mill
Highly plastic, Sufficiently durable but it hardens slowly
Gives fairly strong surface finish
Lime cement plaster → C : L : S = 1:1:6
Sand is mixed with lime mortar → To Prevent Shrinkage & Cracking
lime putty → Adding Hydraulic lime to water, Used only upto 03 days
Fire-resistance mortar
Aluminous cement + powder of firebricks
Gauged mortar (lime-cement mortar)
Lime + Cement + Sand + Water → Process is called Gauging
↑ water retentivity, workability & bonding properties.
used within 02 hrs. after the addition of cement
Lightweight mortar:
adding material like saw dust,wood powder etc. used in sound proof & heat proof construction
Selection of mortar
Cement mortar
Grouting the cavernous rocks = 1:1.5
Dpc & cement concrete roads : 1:2
Gunting, water tank = 1 : 3
Plastering = 1 : 4
Normal brick work = 1 : 6
Hydraulic lime
Water logged area = 1:3
Stone masonry = 1 : 2
Strength : H1 > H2 > M1 > M2 > L1 > L2 (mortar grade)
Mica in sand decrease strength of mortar
LIME (CaO)
Lime → made from dolomite/calcium carbonate
Hydraulicity → Due to clay , Set in damp place, Surkhi is added to lime mortar to impart hydraulicity
Calcite = CaCo3 (Calcium Carbonate)
IS 6923:1973 → Compressive Strength test of lime
Air Slaking → Lime gets softened due to humidity
Surkhi is added to lime mortar → To impart hydraulicity
Karstification → Observed limestone terrains
Slaking
Mixing water to CaO
CaO + H20 → Ca(OH)2 + Heat
Ca(OH)2) → Slaked or Hydrated lime
Silica retard the Slaking Action & increase the rapidity of Setting
When fat lime is slaked → its volume increases by 2 - 2.5 times
Air slaking → Lime gets softened due to humidity
Calcination
Heating CaCO3
CaCo3 → Cao(quick lime) + CO2
Classification of lime
Conventional → 03 types
Poor lime → CaO or purity < 70%
Lean lime/impose lime → Sets on absorbing CO2 from atmosphere
Fat /Rich/White/Quicklime (CaO)
Calcium oxide (CaO) → Quick/lime/lump/caustic lime
Mfd by burning marble, white chalk, calcareous tufa, pure lime stone, seashell and coral.
White washing & Plastering
CaO or purity ≥ 95% & impurities < 5%
Lump lime → Quick lime comes out from the kiln
Hydraulic/Water lime
CaO or purity ≥ 70 - 90%
Used to made lime mortar
Set in water
Hydraulic lime is obtained by Burning of limestone or kankar
Kankar → Calcium carbonates layer
Feebly hydraulic lime → % silica,alumina, iron oxides = 5 - 10%
Moderately hydraulic lime → % silica,alumina, iron oxides = 15 - 25%, Best suited for masonry mortar
Eminently hydraulic lime → Underwater,damp situation & % silica,alumina, iron oxides = 25 - 30%
Class of Lime
IS 712-1984 → 6 Categories of lime
Class A = Eminently Hydraulic Lime → initial setting time = 120 min, Structural purpose
B = Semi-Hydraulic lime
C = Fat lime
D = Magnesium or Dolomitic Lime → Used for finishing coat in plastering and white washing
E = Kankar lime → Masonry mortars
F = Siliceous Dolomite lime
Lime Concrete
Slump = 50 - 75mm
Flexural strength at 90 days = 0.2N/mm²
CS at 90 day = 1.5 N/mm²
Lime Putty
Made from hydraulic lime by adding water
Can be used only upto 3 days
STONE
Petrology → Deals with origin & characteristics of rocks
Transmissibility → Capability of rock or unconsolidated sediment to transmit water through itself considering unit width & full depth under unit hydraulic gradient
load is applied → at 90° to bedding
max bearing capacity → Granite rocks
Stones have a tendency to split along Cleavage
Aquifuge → Basalt, Granite without fissures
Rocks behave as Elastic masses towards operating stresses
Unconformity → Surface of erosion or nondeposition that separates the younger Rock formation from the older Rock formation
Sills → Thin tabular bodies of magma which essentially penetrate parallel to the bedding plans of foliations of the country rocks
Properties of good stone
G = 2.7
coeff of hardness ≥ 17
% of water absorption ≤ 5% of wt of stone
toughness index ≥ 13%
crushing strength ≥ 100 Mpa or 1000kg/cm²
% wear in attrition test ≤ 30%
wearing resistance < 3%
Max permissible wear in stone for road work = 2 %.
well seasoned before use (s t = 6 - 12months)
Geological Classification
Igneous/Primary/unstratified/Eruptive
Plutonic or deep seated: large depth → Granite, Gabbro, Syenite.
Hypabyssal →Small depth → Dolerite
Volcanic → Earth surface → Basalt & trap
Intrusive → Pegmatite, Granite, gabbro, diorite, Dolerite
Extrusive → Basalt & trap
Ex → Feldspar, mafic rocks, Rhyolite
Mafic rocks → Silica = 45 - 55 %
Unstratified rocks possess crystalline & compact grains
Sedimentary/stratified/aqueous/fossil
Accumulation of weathered deposits of igneous rock
Constituents → Celcite(CaCO3), Quartz, clay & rock fragments
Calcite is calcium carbonate (CaCO3).
Mechanical:
Chemical: Gypsum, Dolomite
Organic: limestone
Fragmental: sandstone
ex. Shale, laterite, Calcite, Fossils, Conglomerate, Coal, GRAVEL, lignite
limestone → stratification is vague or unnoticeable
Metamorphic
Due to heat & excessive pressure
Marble is queried by wedging
ex. Anthracite, Schist, Serpentine
Basalt → Laterite (A)
Mudstone/Shale → Slate(A)
Sandstone/Quartz → Quartzite(S)
Granite → Gneiss (S) (CS → Gneiss > Granite)
Limestone → Marble(C)
Physical Classification
Stratified: layered structure ex. All Sedimentary, Slate.
Unstratified: Crystalline & compact eg. All igneous, marble
Foliated: Split in one direction eg. All metamorphic except quartz & marble.
Chemical Classification
Argillaceous → Clay or aluminium (Al2O3) eg. Laterite, mudstone, shale, slate, kaolin
Calcareous → Calcium carbonate eg. Marble, limestone
Silicious → Silica eg. Quartz, Quartzite,Gneiss, Granite
Other classification
Soft stone → Ornamental & architectural beauty
Hard stone → Highest bearing capacity & used in rubble masonry
Lightweight → Dome Construction
Heavy wt → Retaining wall
Monomineralic → Quartz sand, Pure Gypsum & magnetite
Polymineralic → Basalt, Granite
Use & Properties of Stones
Ammonium dynamite: tunnelling in soft rock
Granite → Quartz+feldspar+mica, sea wall, ballast, decoration, pier, can polish easily,masonary work in industrial areas exposed to smoke & chemical flumes, G = 2.6-2.9, CS = 77 - 130 N/mm², Hypidiomorphic texture.
Bauxite → Hydrated aluminium oxide having dull lustre
Basalt: extremely fine grained
Black marble: Jaipur
Chalk : cement
Compact sand stone: more fire resistant
Compact Limestone: Great thickness in non-crystalline texture with earthy Appearance
Deccan trap (basalt) → Foundation of blast furnaces.
Dolomite: 45% carbonate of magnesia & a Sedimentary rock. Used in foundation,wall, column,Arches,lintels.
Emery : carborundum stone , very hard abrasive material
Gypsum : CaSo4.2H20 (calcium sulphate dihydrate)
Hydrolysis: feldspar ( Granite ↔ Clay)
Laterite → Carving & Ornamental work, Rough stone work
Limestone: mfd of cement, cs = 550kg/cm²
Marble : Ornamental work, flooring.
Quartz : G = 2.65.
Quartzite → More weather resistance, Road metal work
Shingle: water bound pebbles
Sandstone: Granular crystalline, CS = 650kg/cm²
Slate → DPC, Roofing, Flooring, least % of water absorption.
Syenite: Deep seated plutonic rock.
Loose sand & gravel has the highest porosity
Minerals
Quartz,mica,feldspar (IR)
in minerals Basal type of cleavage is observed
TEST
Durability test
Smith's test → Presence of earthy, mineral, water soluble matter & muddy substance, Deterioration of stones when immersed in water
Crystalline test → Prescribed by BIS
Acid test → Weather Resistance, Amount of calcium carbonate in sandstone
Brard's test → Frost resistance
CS test
For good building stone → CS > 100 Mpa
Rate of loading in crushing strength test = 40 tonne/minute
CS of Stone depends on Texture and Specific gravity of the stone
Limestone = 55 N/mm²
Sandstone = 65 N/mm²
Granite = 70 - 130N/mm²
Deccan trap (Basalt) = 150 N/mm²
Hardness test
Mohs Hardness Number → Talc = 1 (Softest), Gypsum = 2, Calcite = 3, Feldspar = 6, Quartz = 7, Topaz = 8, Diamond = 10(Hardest), Scratch with fingernails = 2-3
Brinells HT: indenter hard steel ball
Schmidt hammer test → in situ test
Abrasion test → To determine hardness or resistance against Scratch
Thumb nail & knife test → To determine hardness
COH = 20 - (Loss of wt gm)/3
Attrition test
Attrition test → Durability against Grinding action, Rate of wearing, Bearing value
Max permissible wear of stones for road work = 2%
Good building stone wearing resistance < 3%
Porosity test
Water Absorption < 5% → Good building stone
Rejected → if WA > 10%
To dry quarry sap of a freshly quarried stone it is exposed to open air for 6 - 12 months.
Impact test or toughness
Moderate tough = 13 - 19
Highly tough > 19
Split tensile strength test of stone
Cylindrical specimen
Dia > 4 x max size of CA
Dia = 50mm → dia ≤ length ≤ 2 x dia
Height = 100mm
Specific Gravity Test
Quartz → G = 2.65
Calcite → G = 2.71
Other Tests
Glassometr → Polish on the surface quality of polished granite
Dock & Harbour → Weight test is important
Quarrying
Taking out stone of various size from natural rock
Or Production of natural stones.
use of Gunpowder, Gun cotton, Dynamite.
Drilling → Blasting → Mucking → Concreting
Blasting powder: 65%saltpetre, 20%sulphur,15%charcol.
Dynamite: 25% saturated sandy earth + 75% Nitro glycerine
Ammonia Dynamite: explosive used for tunnelling in soft rocks
explosive for blasting →Kg (kilograms)
Quantity of explosives (gm) = L²/0.008
Powder factor → Amount of explosives required to fracture a unit vol of rock
Quarry sap → Ntrl moisture in newly quarried stone.
Method of Quarrying
Excavation
Wedging → marble
Heating & Burning
Blasting
Note
Drilling equipment → Jack hammer, Shot drill, Drifter
Dressing of Stone: immediately after quarrying, to provide a smooth face & regular face.
Dressing Tools; face hammer, mallet, point chisel.
Spalling Hammer : For rough dressing of stone
Jumper : for making holes in rock
Drift: tunnelling in rock
Sills: thin tabular bodies of magma which essentially penetrate parallel to the bedding planes of foliations of the country rocks.
Lava = 45% Calcium oxide + 35% silica.
Hydrolysis: Chemical weathering associated with feldspar, Granite changing in Clay.
Drift method of tunnelling is used to construct tunnels in Rocks
Full grout: bitumen is allowed to fill in the full depth of the stone layer
Rock mass rating (RMR)
Very good rock = 81 - 100
Good = 61 - 80
Fair = 41 - 60
Poor = 21 - 40
Very poor < 20
Rock Quality Designation
RQD = (Length of core pieces > 10cm)/Total core length
Stone masonry
Cement: Sand = 1:3
i. Rubble masonry
Hard stones → dressing is not possible→irregular shaped stones.
e.g. Red fort,
Rm is of 06 types
Dry rubble m : Stone masonry without mortar
Course Rm : Stone of same height
Uncourse Rm : cheapest roughest & poorest form of stone masonry
ii. Ashlar masonry
uses well dressed stones with sharp, straight, & smooth faces
PAINTING, PLASTERING & POINTING
1). PLASTERING/PARGETTING/PINKING
Surface has to be Rough
IS code: 1661 gives specification about cement plaster.
Thickness = 12mm generally, 1st coat is called undercoat = 10 - 15mm
Palastering = 2 x wall Area.
Wood = 3coats
Mud plaster = Mix of heavy clay & water, doesn't require curing.
Parging: Thin coat of plaster or mortar for smooth surface to rough masonry or for sealing it against moisture
Rules of deduction
Area opening < 0.5 m² → No deduction
Area opening = 0.5 - 3 m² → One side deduction
Area opening > 3 m² → Both side deduction
Cross/Plaster wall → Thickness of wall
T-jⁿ of the wall for total length of centre line → 1/2 thickness of wall.
L-jⁿ → No deduction
End of beam ,post,rafter,.etc upto 0.05m² → No deduction
Corners → No deduction.
2).POINTING
Raking out joints to fill with mortar.
3).PAINTING
Done after plastering
Applying paint, Pigment, Color
Munsell references → classifying Paints
Flaking → Detachment of paint film from surface
Resin → insoluble in water & soluble in spirit
French polish → Dissolving resin in spirit
Different types of Paints
Enamel paint → Snow crete, base( white lead,zinc) +Vehicle (varnish), Surface shine like radium.
Cellulose paint →oil storage tank, Duco is a CP
Asbestos paint: rust free, most resistant to fire (incombustible), it is a organic substances
Anticorrosive paint is Black in colour
Cement Paint → Covering capacity = 4 m²/kg per coat.
Emulsion paint → stucco plaster, bricks & masonry surface.
Aluminium paint → resisting Corrosive reaction
Bituminous paint → iron work under water
Anti Corrosive paint → Surface exposed to high temperature.
Oil Paint → Normal Paint
Various Constitutes of an Oil Paint
i. Base
it makes the paint film opaque
Ex. white lead, red lead, oxides of zinc & iron.
timber painting → white lead
iron & steel → red lead
ii. Pigment
Hide surface imperfection & to impart desired colour,
Zinc oxide, white lead lithophone → white colour
Vermillion → Red
Indigo, Prussian blue → Blue
Burnt siena → Brown
Red lead → Corrosive resistance.
iii. Vehicle/Binder/Carrier/Drying oil
Aluminium: coat of Al oxide
Give binding properties & spread evenly & uniformly on surface
Ex. linseed oil, Poppy oil, Tung oil, Varnish (for enamel paint).
iv. Solvents/thinner
Volatile dilutⁿ, petroleum, spirit, naphtha, & turpentine oil
To Dilute the vehicle prior to the application of paint on the surface
v. Driers/plasticizer
8%
Accelerate drying property
vi. Adulterant:
increase durability & decrease weight
vii. Extenders:
↑es vol.
viii. Waterproofing base:
Titanium oxide.
Pigment vol concentration no.
PVCN = Pigment vol / Total non volatile material vol.
Exterior surface of house = 28 - 40.
Munsell colour reference
Used for classifying Colour of paints
Hue (Basic colour)
Value (Lightness)
Chroma (colour intensity)
Defects in paints :
Peeling → Formⁿ of patch, swelling of paint due to moisture
Blistering → Swelling of paint due to oil or volatile substance, vaporisation of entrapped moisture of solvent.
Crazing → Fine hair cracks
Caking → Settling of pigment particles of paint into a Hard compact mass, which is not easily redispersed by stirring.
Popping →Conical holes
Bleeding →Diffusion of coloured material into the upper coat from the under coat.
Bittiness:
Blooming → Appearance of whitish substance on surface of varnish or enamel
Grinning → imperfect opacity of paint, background & its defects clearly visible.
DISTEMPER
Distemper is water based wall paint or white paint
Carrier → water.
Constitutes: chalk lime(base), glue, water(thinner)
Lead ≤ 300 ppm.
Used as interior paint for homes
Not used for surface exposed to weather bcz got washed away
Applied on wall for two coating
1kg of distemper uses 0.6 litres of water.
Outturn = 35 m² per day considering 8 hrs.
VARNISH
Resin(copal,lac) + drier(litharge) + solvents (linseed oil)
Resin in oil(linseed oil) , alcohol, or turpentine + drier
it is liquid part of paint
Oil varnish → Resin + oil + turpentine
Sorit varnish →Spirit + shellac
DPC: Damp Proof Course
Plinth level to full width of plinth wall
Basement layer to restrict moisture
Not provided at sills of door & Varandha opening
Waterproofing Materials
Polyethylene & Polyvinyl chloride resin
Polyester & Phenolic resin
Polystyrene & Polypropylene Plastic
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