18/12/25-stone masonry grade3 part3&4

Which type of ashlar masonry permits maximum 3 mm mortar joints?

• Ashlar Rough Tooled
• Ashlar Rock Faced
• Ashlar Fine Masonry
• Ashlar Block in Course

Answer explanation

Fine ashlar masonry uses very accurately dressed stones with joints not exceeding 3 mm

The simplest joint in stone masonry where stones are placed directly in contact is

• Rebated joint
• Butt joint
• Plugged joint
• Tabled joint

Answer explanation

Butt joint also called square joint involves direct contact without interlocking

Which joint is mainly provided to prevent direct water penetration

• Tabled joint
• Tongued and grooved joint
• Rebated joint
• Dowelled joint

Answer explanation

Rebated joints create an overlapping step that sheds water away from the joint

Which ashlar masonry gives a natural rugged appearance with a margin strip

• Ashlar Fine
• Ashlar Chamfered
• Ashlar Rock or Quarry Faced
• Ashlar Block in Course

Answer explanation

Rock faced ashlar has a rough central face with neatly dressed margins

Which joint is mainly used to resist lateral sideways forces

• Butt joint
• Plugged joint
• Tabled joint
• Cramped joint

Answer explanation

Tabled joints provide a wide bearing surface to resist lateral pressure

Which ashlar masonry is commonly used for sea walls retaining walls and bridge abutments

• Ashlar Fine
• Ashlar Rough Tooled
• Ashlar Chamfered
• Ashlar Block in Course

Answer explanation

Block in course masonry is suitable for heavy engineering works

In a rebated joint the minimum length of rebate should be

• 10 mm
• 80 mm
• 70 mm
• 100 mm

Answer explanation

Standard practice commonly mentions a rebate length of about 70 mm in such joints

Assertion :Tongued and grooved joints are effective in preventing sliding of stones

Reason :They prevent sliding because the stones are bonded using high strength cement mortar

• Both A and R are true and R explains A
• Both A and R are true but R does not explain A
• A is true but R is false
• A is false but R is true

Answer explanation

Sliding resistance is due to mechanical interlocking not mortar strength

Assertion : Cramped joints are preferred where stones may separate under load

Reason : Metal cramps tie stones together and provide lateral stability

• Both A and R are true and R explains A
• Both A and R are true but R does not explain A
• A is true but R is false
• A is false but R is true

Answer explanation

Cramps prevent stones from pulling apart and increase stability

Which joint uses dovetail shaped mortises filled with molten lead

• Dowelled joint
• Plugged joint
• Cramped joint
• Saddled joint

Answer explanation

Plugged joints use molten lead poured into dovetail shaped holes to lock stones