STONE & STONE MASONRY - Building Materials short notes and previous year questions

STONES

CLASSIFICATION : 

I. GEOLOGICAL 

II. PHYSICAL 

III. CHEMICAL 

1. GEOLOGICAL CLASSIFICATION 

i. IGNEOUS ROCKS : 

• formed by the solidification of molten magma 

• On the basis of cooling classified into 3

Plutonic rocks
• Formed at considerable depth
• Slow cooling
• Coarse grained , crystalline 

• Most commonly used 

• Granite, pegmatite, diorite, gabbro 

Hypabyssal rocks 

• Formed at shallower depth 

• Quick cooling 

• Fine grained , crystalline 

• Dolerite , quartz 

Volcanic rocks

• Formed at the surface 

• Very rapid cooling 

• extremely fine grained 

• Basalt , pumice stone , trap

2. SEDIMENTARY ROCKS 

• Formed by the deposition of products of weathering of preexisting rocks 

• 4 types of deposits 

i. Residual deposits : some portion of weathered product remains at the site of origin 

ii. Sedimentary deposits : insoluble broducts carried away in suspension 

iii. Chemical deposit : products carried away by solution gets deposited by physiochemical process like evaporation 

iv. Organic deposits : deposited through organisms 

• Examples : Mudstone, Limestone, Lignite, Laterite, Gravel, Gypsum, Shale, Sandstone, Chalk, Kankar, Dolomite 

3. METAMORPHIC ROCKS 

• Formed by change in characteristics of previous existing rocks under High heat and pressure 

• Process is called as metamorphism ( > 200 *c ) 

i. Thermal metamorphism : heat is the main agent 

ii. Cata clantie metamorphism : pressure 

iii. Dynamo thermal metamorphism : high heat and stress 

iv. Plutome metamorphism : at greater depth uniform pressure and heat causes metamorphism 

• Example : Moorum, Marble, Slate, Quartzite, Gneiss, phyllite

METAMRPHISM

GRANITE - GNEISS 

LIMESTONE - MARBLE

SANDSTONE - QUARTZITE

MUDSTONE - SHALE

TRAP & BASALT SCHIST

QUALITIES OF A GOOD BUILDING STONE 

 Crushing strength > 100 N/mm2 

 Percentage wear <= 3 % 

 Well-seasoned : 6 - 12 months 

 Specific gravity > 2.7 

 Porosity should not be greater than 5 % 

 Water absorption by weight >/ 0.6 

 Moisture content : 5 % 

TESTS ON BRICKS 

1. ACID TEST 

• To check the weathering quality 

• Check presence of caco3 

• 1 % hcl - 7 days immersed 

2. ATTRITION TEST 

• Rate if wear 

• Devals attrition testing machine 

3. ABBRATION TEST 

• Hardness 

• Los Angeles abrasion testing machine 

4. HARDNESS TEST 

• Hardness 

• Dorrys testing machine 

• 25mm dia & 25mm length cylinder 

5. IMPACT TEST 

• Tests toughness 

• Toughness index is determined 

6. CRUSHING TEST 

• Measures compressive strength 

• 40 mm x 40 mm sample 

7. SMITH'S TEST 

• Tests presence of soluble matter

TOUGHNESS INDEX 

• < 13 NOT USED 
• 13 - 19 MODERATE TOUGHNESS 
• >19 HIGH TOUGHNESS

COEFF OF HARDNESS 

• < 14 POOR HARDNESS 
• 14 - 17 MODERATE HARDNESS 
• >17 GOOD FOR ROAD WORKS

ROCK MASONRY 

• Cement mortar : 1:3 

• High load carrying capacity, thermal insulation 

TECHNICAL TERMS 

• CORBEL : A short stone cantilever jutting from the face of a wall to form a bearing 

• CORNICE : A projection which crowns a wall, any horizontal division of a wall, or an architectural feature 

• BEDDING PLANE : The plane along which the stones can be separated into different layers 

• DRIP STONE : a projecting stone with under surface throated to prevent water from reaching wall 

• GROUTING : process of filling joints and cracks between stone 

• MOLDING : ornamental feature given to construction to improver appearance 

• TEMPLATE : piece of stone at ends of beam to distribute load over large area 

• THROUGH STONE OR BOND STONE : The stone extending through the entire thickness of a wall to increase its lateral stability is called a through or bond stone. 

• PARAPET : A low wall constructed around the terrace of a building having flat roof is called parapet wall. 

• COPING : A special course provided at the top of wall preventing penetration of rainwater from entering the wall. 

• STRING COURSE : A distinctive course or band continued across a whole facade which may be defined by its position e.g. a sill course. 

• BUTTRESS : The stepped masonry projections which is intended to provide lateral strength to the wall is called buttress 

• STOOLING : horizontal seating to receive jumps and mullion 

• WEATHERING : dressing stone in a sloped fashion to draw water 

• THROATING : cutting grove to draw water 

• LACING : horizontal course to strengthen the bonds of wall 

• BUSHING : external projections on stone surface 

• PILASTER : a right angled columnar projection 

• APEX : coping at top of gable wall 

• SPRINGER : coping at foot 

• SKEW CORBEL : corbel below the gable roof 

• KNEELER : b/w apex and skew corbel 

• FINAL : ornamental finishing at apex 

• LABEL/DRIPSTONE : projecting course just above the door/window

JOINTS IN STONE MASONRY 

1. BUTT JOINT / SQUARE JOINT : 

• In butt joint, two stones are placed adjacent to each other 

• This is used for arch work, coping on gables, stones laid on slopes, etc. 

2. LAPPED OR REBATED JOINT 

• Min length of rebate : 70 mm 

3. TABLE JOINT 

• a joggle makes in the bed of the stone to check the lateral movement 

• In case, the lateral pressure is very high this type of joint is more suitable. 

4. TONGUED AND GROOVED JOINT / JOGGLED JOINT 

• projection of one stone fits in the corresponding groove of adjacent stone. 

• This type of joint also prevents the sliding of stones 

5. RUSTICATED JOINT 

• the edges of the joint sunk below the plane of face work. 

• The different types of rusticate joints: 

i. channel joint, 

ii. vee joins 

iii. vee and channeled joint. 

6. PLUGGED JOINT 

• A dovetailed mortice is created 

• Molten lead or rich cement mortar pour in the dovetail. 

7. DOWEL JOINT 

• In this joint dowels of slate, gunmetal, brass, bronze, etc. are introduced to connect the two pieces of stone. 

• The dowel inserted into holes drilled in each stone piece and secured in position with cement. 

8. CRAMPED JOINTS 

• A cramp is a piece of metal with ends turn down. 

• A dovetail groove makes in two pieces of stone and the cramped place in position. 

• Later the rest of the groove grout with lead or cement mortar. 

• Min length of cramp : 200 - 300 mm , thickness 5 - 10 mm 

9. SADDLE OR WATER JOINT 

• Stone is rounded off to protect joints 

• Helps in diverting water

TOOLS USED IN STONE MASONRY 

1. SPALL HAMMER ( large ) : used to dress stones in quarry 

2. MASH / WALLER'S HAMMER : used for normal dressing 

3. CLUB HAMMER : used to strike narrow headed chisel 

4. SCABBING HAMMER : to remove bushings 

5. PUNCH : used to dress stone surface as rough 

6. BROAD TOOL/NICKER :to form chisel line of the surface of stone 

7. BOASTER : cut soft stone

PREVIOUS YEAR REPEATED QUESTIONS BASED ON STONE AND STONE MASONRY