To evaluate the strength grade of mortar test piece, the standard curing test piece of 28d shall prevail. The specimen is a cube with a side length of 70.7 mm, and 6 specimens are 1 group. The number of groups made shall meet the following requirements:

1, mortar test blocks with different mortar test blocks strength grades and different mixture ratios should be made separately, and the test blocks should be taken with the organization and cannot be selected.

2, important and main masonry, each shift system for 2 groups. General and secondary masonry, each class can do 1 group.

3, arch ring mortar specimens should be with masonry curing specimens under the same conditions at the same time, to check the strength of each construction stage.

According to Code for Design of Masonry Structures and Code for Acceptance of Masonry Engineering, the strength grade of mortar test blocks is determined by the arithmetic mean of compressive strength of six 70.7mm× 70.7mm×70.7mm test blocks under the conditions of 20C and 60% ~ 80% humidity for 28 days. Mortars are divided into M20, M 15, M 10, M7.5, M5 and M25 * *. Mixing mortar test block should meet the design requirements of the type and strength grade, and meet the requirements of consistency, good water retention and uniform mixing. The strength grade of mortar test blocks used for walls and columns that are shaken and are more than 6M high should not be lower than M2.5, and the strength grade of mortar test blocks in cold areas and humid environments below the ground is generally improved by one level.

Size of mortar test block

How big is the mortar test block?

Mortar test blocks are generally fixed in size, mainly cubes with a side length of 70.7 mm. The mortar strength grade is determined according to the compressive strength value of 28 days after curing at (20 2)℃ and relative humidity above 90%.