Mortar is a mixture of Portland cement, hydrated lime, sand (sized between 1/8") and 100 mesh) and water. Masonry cement, which contains hydrated lime, can be used instead of Portland cement.
Mortar has the same basic ingredients as concrete but the proportions of the mix make it more workable and quicker to set. To increase its workability you can increase the amount of water or the amount of hydrated lime used in the mix.
To increase mortar strength...
Increase the amount of cement.
Decrease the amount of water relative to the amount of cement.
Decrease the amount of hydrated lime.
Increase the amount of Portland cement relative to the amount of masonry cement.
The mix must be mixed thoroughly. A power mixer is recommended, though small quantities can be mixed by hand. Mortar will begin to cure and stiffen once it is mixed. If this occurs under a 2 ½ hour period you can add a small amount of water to increase workability. After 2 ½ hours the mortar should be thrown away. (These time limits assume 80 F or hotter outside temperature. If the temperature is below 80 F the time limit can be increased to approximately 3 ½ hours).
Portland Mix Proportions by Volume
Type
Portland Cement
Hydrated Lime or Lime Putty
Sand
M
1
1/4
3
S
1
1/2
4 1/2
N
1
1
6
O
1
2
9
Masonry Mix Proportions by Volume
Type
Portland Cement
Masonry Mix
Sand
M
1
1
6
S
1/2
1
4 1/2
N
1
3
O
1
(Type I or II)
3
Bon Tool Co. has made a serious effort to provide exact and current information, but does not guarantee the accuracy of the data. Bon Tool Co. cannot assume responsibility for the application of information nor guarantee results.
