Use of marble dust as paste replacement for recycling waste and improving durability and dimensional stability of mortar

Lots of marble dust (MD) are generated in stonework factories and just dumped as waste causing environmental problems. Some researchers proposed to use the MD as cement replacement or aggregate replacement in mortar or concrete but the benefits in cement content reduction and performance enhancement are quite limited. Recently, the authors have developed a new method of using inert waste or fillers as paste replacement for greater benefits. By this method, the waste or filler is added to replace an equal volume of cementitious paste without changing its mix proportions. In this study, the authors applied this method to the use of MD in mortar. A series of mortar mixes with varying MD volumes and water/cement ratios were made for mini slump cone test, carbonation test, water absorption test and drying shrinkage test. The test results revealed that adding MD as paste replacement could substantially improve the carbonation and water resistances, reduce the shrinkage strain and rate, and at the same time, reduce the cement content by up to 33%.