Punching shear resistance of lightweight aggregate concrete slabs

Provisions for the use of structural lightweight aggregate concrete are included in British codes of practice, but limitations are applied as to the design values that may be used. This Paper is concerned with the strength in shear of slabs subjected to punching, which is limited in the codes to 80% of that for normal-weight concrete of the same compressive strength. Tests on slabs made with five different lightweight aggregates are described; on the basis of the results it is concluded that the code provisions are unnecessarily conservative.