Admixtures : their effect on reconstituted limestone

Abstract

The depleting resource of Globigerina Limestone and the waste generated by the same resource has attracted more interest amongst researchers to produce an artificial stone made from the waste. Mechanical and physical properties of any building block are very important for its success hence, extensive studies on the physical characteristics of reconstituted limestone have been carried out locally between 2011 and 2013. Building upon previous studies, this dissertation focuses on the effects of admixtures on the strength and durability of reconstituted limestone. Apart from the normal constituent materials, different dosages of Sika®-1 (waterproof) and Sika® Plast60 (VP) (superplasticizer) were added to the mix. Different mixes with a variation in the amount of admixture were studied in order to identify the effect of admixture on the compressive strength. Apart from strength, the performance of reconstituted limestone in the local environments is also important. Hence, the same mixes were then tested for porosity, water absorption, and salt crystallization. The results obtained were then compared directly with natural Globigerina Limestone which provided a suitable reference for comparison of results. The results obtained pointed out that as the Sika® Plast60 (VP) content increased, the characteristic strength was enhanced while the porosity and water absorption decreased. These specimens also demonstrated better resistance to souium sulphate. As the amount of Sika®-1 increased, only a slight variation in strength and porosity was noted. On the other hand, water absorption decreased and a significant resistance to salt crystallisation was observed.