Mortars Flashcards
1
Q
What are they used for?
A
bed joint masonary units (bricks)
2
Q
How were mortars used up to 70 years ago?
A
> they were sand-lime (SiO2 and slaked lime (Ca(OH)2)
slow setting done with drying via rxn with CO2 in air: Ca(OH)2 + CO2 –> CaCO3 + H2O
wouldn’t set in wet environment
3
Q
What are contemporary mortars?
A
> sand, cement, slaked lime in a 6:1:1 ratio
set more rapidly and can set in water
4
Q
What component of the mortar increases workability? Which components affect strength?
A
> the lime increases workability
more SAND and LIME content decrease strength of mortar
5
Q
Why shoudl the mortar be weaker than the brick?
A
So stresses like thermal expansion or settling result in PREFERENTIAL CRACKING of the mortar, which is easier to repair
