Sand is part of the aggregate mix and determines the abrasiveness of concrete. Small aggregate is usually sand. Sand can either be sharp (abrasive) or round (non-abrasive). To determine the sharpness of sand, you need to know where the sand is from. Crushed sand and bank sand are usually sharp; river sand is usually round.
Green concrete is more abrasive than cured concrete. This is because when concrete is not fully cured there has not been enough time to allow the cement to gain strength to hold all the sand in place; sand is scraped or torn free from the surface being cut by the cutting action of the blade. As this free sand works past the spinning blade, it abrades the segment and core, thus accelerating wear. More loose sand means more abrasiveness.
Amount of Steel Reinforcing (Rebar)
Heavy steel reinforcing tends to make a blade cut slower. Less reinforcing tends to make a blade cut faster. Light to heavy rebar is very subjective term. Examples include:
Wire mesh, single mat
#4 rebars every 12" on center each way (OCEW), single mat
#4 rebars every 12" on center each way (OCEW), double mat
"Heavy" rebar can also result from different grades of steel. Typical rebar is grade 40 steel. Grade 60 steel would make the example of #4 (medium) rebar above into a heavy rebar. Rebar gages (diameter of the bar) are measured in eights of an inch - #4 rebar is ˝' diameter ( 4 x 1/8"), #5 is 5/8' (5 x 1/8").