Civil war-Day 17-Oct 13-KWA-TIMBER,CEMENT,FILLERMATERIALS,LIME

Which among the following class of lime is used as mortar for masonry works?

• Class A
• Class B
• Class C
• Class D

Answer explanation

Class B (semi-hydraulic) lime is used for masonry mortars.

IS Code which recommends the methods of testing of small clear specimens of timber is —

• IS 1141 : 1958
• IS 1708 : 1986
• IS 401 : 2001
• IS 399 : 1963

Answer explanation

IS 1708:1986 specifies testing methods for small clear specimens of timber.

For complete hydration of cement, the water–cement ratio needed is —

• Less than 0.25
• More than 0.25 but less than 0.35
• More than 0.35 but less than 0.45
• More than 0.45 but less than 0.60

Answer explanation

Complete hydration typically needs w/c ≈ 0.38–0.42; hence 0.35–0.45 is correct.

According to chemical composition, total sulphur content in cement shall not be more than —

• 1.02%
• 1.5%
• 2.75%
• 4%

Answer explanation

Limit for total sulphur content is 2.75%.

A combined mortar with principal binding material (x), secondary binding material (y) and sand (z) is designated as —

• x : y
• x : z : y
• y : z : x
• x : y : z

Answer explanation

Notation x:y:z represents binder : secondary binder : sand.

The mortar having bulk density less than 15 kN/m³ is called —

• Heavy mortar
• Light weight mortar
• Lime mortar
• Gauged mortar

Answer explanation

Bulk density < 15 kN/m³ ⇒ light-weight mortar.

Early attainment of strength in rapid hardening cement is mainly due to —

• Gypsum
• Finer grinding
• Di-calcium silicate
• Tri-calcium aluminate

Answer explanation

Rapid hardening cement is ground finer to increase early strength.

An example of an endogenous tree is —

• Jack
• Mahogany
• Bamboo
• Rosewood

Answer explanation

Bamboo is an endogenous tree; growth occurs inward by deposition of tissues.

The process of hardening of lime after it has been converted into paste form is known as —

• Setting
• Slaking
• Calcination
• Hydraulicity

Answer explanation

Setting is the hardening of lime paste; slaking is CaO → Ca(OH)₂.

“MM 1.5” means —

• Masonry Mortar of cement content 1.5 bags
• Mild Mortar of cement content 1.5 bags
• Masonry Mortar of compressive strength 1.5 N/mm²
• Mild Mortar of compressive strength 1.5 N/mm²

Answer explanation

MM 1.5 denotes compressive strength 1.5 N/mm² for masonry mortar.