Study on plastic shrinkage of coconut shell concrete slab made with M-sand

Coconut shell (CS) used in the production of coconut shell concrete (CSC) is one of the sustainable concretes developed in the past one decade. This novel idea of using CS waste not only produces the green concrete but it also minimizes landfills area of dumping CS waste. Most of the studies on CSC used river sand as fine aggregate. But in the present situation, there is a necessity to find the replacement materials for river sand to safeguard the natural resources. The immediate resources available for this purpose are the use of quarry dust and manufacturing sand (M-sand). Though M-sand-used concrete studies are done by many researchers, its usage in combination with CS for the production of CSC is very limited. Therefore, this study aimed to produce CSC using M-sand as fine aggregate in its place of river sand and was concentrated to study the plastic shrinkage characteristics of M-sand-used CSC, because shrinkage properties of any concrete are also very significant which decides the durability of the concrete and also the esthetics outlook. Therefore, an experimental study was conducted to investigate the characteristics of CSC produced with M-sand, and for comparison purposes, conventional concrete (CC) produced with M-sand was also studied. Ten mixes in total were produced: five mixes each in the case of CSC and CC, respectively. Five mixes were designated as CCM1 to CCM5 in the case of CC and CSCM1 to CSCM5 for CSC, in which the river sand was replaced 0, 25, 50, 75 and 100% by M-sand in both CC and CSC mixes. The study found that the compressive strength increased and plastic shrinkage crack area decreased as the percentage of M-sand replacement increased in both CC and CSC. Therefore, the use of M-sand in its place of river sand is beneficial in the aspect of strength and plastic shrinkage of concrete, and hence, their durability property could be enhanced.