Abrasion resistance – lightweight aggregate
For most purposes the abrasion resistance of a floor containing lightweight coarse aggregate can be specified exactly as for a normal weight aggregate concrete floor, provided natural sand is used as the fine aggregate. Guidance on specification for abrasion resistance is given in BS 8204, Screeds, bases and in situ floorings, Part 2, Concrete wearing surfaces, and in Technical Report 34.
Although in general lightweight coarse aggregate can be used satisfactorily, there are a number of factors that should be considered. Care must be taken to ensure that a layer of mortar covers all the lightweight coarse aggregate. If the aggregate is exposed for any reason, its abrasion resistance may be lower than normal weight coarse aggregate, leading to significant surface wear. It follows that if the surface mortar layer is removed by grinding to correct flatness, the ground surface may have a lower abrasion resistance that the rest of the floor.
Further information is given in Concrete Advice No. 11, Abrasion resistance of floors containing lightweight coarse aggregate.