Mortar to be used to bond the AAC shall have less or more compression strength?

For Cross checking purpose we take the AAC block of 600mm (L) X 200mm (H) X 150mm (W) and the AAC block bed adhesive of 3mm.

AAC mortar's compression strength is tested by making the cube of 70.6mm X 70.6mm X 70.6mm and let say, the compression strength obtained is 18N/mm^2. 

Means when the wall is constructed using 3mm bed thickness the compression strength will be 18 / 70.6 X 3mm = 0.76 N/mm^2.

The AAC block's compression strength is tested by making the block of size 150mm X 150mm X 150mm (the below is the test certificate available on line).

Means on block of 150mm X 150mm X 150mm takes the load of 6N/mm^2 (I am considering the height of 5.74 say 6 N/mm^2). Look in to the below image, to know how many blocks of 150mm X 150mm X 150mm can be there in 600mm X 200mm X 150mm:

Let calculate: Cmtr for 150mm X 150mm X 150mm = 3375000 mm^3

                               for 600mm X 200mm X 150mm = 18000000 mm^3
No of blocks = 18000000 / 3375000 = 5.33 No's.
Means in the system one AAC block will be having the compression strength of 5.33 No's X 6 N/mm^2 = 31.98 N/ mm^2.
Hence, AAC block adhesive used will safely transfer the load the block below to it or to the substrate.

"It is extremely interesting to note that, although the compression strength is low, the modulus of elasticity is very high compared to the common table molded bricks and solid concrete blocks. This may find special benefit in the limiting deflection due to lateral loads.".....From: http://www.ijscer.com/uploadfile/2015/0427/20150427030333887.pdf

For more details about AAC blocks and AAC Block mortar: https://annayyachandrashekar.blogspot.com/2018/05/aac-blocks-and-adhesive-for-installation.html

For method of construction of wall using Brick / solid blocks / Hallow blocks, refer to: https://www.myhomemydesign.in/block-work-masonry-works-in-construction/ Many thanks to Google.com and doc88.com from where the images and details were took.