Which two properties should mortar sand be tested for?

Mortar sand plays a critical role in the quality and performance of masonry work, making it essential to assess its properties before use. Testing for cleanness and grade is vital because these factors directly influence the adhesion and durability of the mortar.

Cleanness pertains to the absence of impurities, such as dust, organic matter, or clay, that could weaken the bond between the mortar and the masonry units. If the sand is not clean, it can reduce the strength and workability of the mortar, which is crucial for structural integrity.

Grade refers to the particle size distribution of the sand. It is important that the sand meets specific grading requirements to ensure a proper mix that allows for adequate workability, strength, and finishing characteristics. If the sand's gradation does not fall within specified limits, it can lead to issues like increased shrinkage or poor curing.

Considering these reasons, focusing on cleanness and grade ensures that the mortar produced will perform effectively in its intended applications.