Abstract
Growing awareness on sustainability has prompted several researchers towards incorporation of waste,like shredded rubber tyres,in concrete as a replacement to aggregate[1,2].A major challenge observed while using light-weight aggregate(LWA),like shredded rubber tyre waste,is segregation[2].Segregation results in a decline of mechanical and durability characteristics of concrete[3].Segregation limits the application of lightweight aggregates(LWA)in terms of concreting[2,4].
Segregation in concrete has been attributed to several factors which including rheological properties of the mix,density and shape of aggregate,and energy of compaction[3,5,6].Energy of compaction can be broken down to its two aspects rate of compactional energy and time duration of compaction.Of the two,studies on segregation has been done by varying time duration of compaction for a constant rate of energy[5,6].Influence of rate of compactional energy and time duration of compaction was not discussed in the observed literature.For the same,this study experimentally analysed the dependency of segregation on time duration of compaction,rate of compactional energy and total energy of compaction for expanded polystyrene beads(EPS)as LWA.
Fresh mortar of dif ferent rheological characteristics,embedded with EPS beads as LWA,have been subjected to varying degree of impact energies for representing different rates of compactional energy and time duration of compaction.Segregation is quantified using distribution of EPS beads in the mortar matrix.Analysis showed that subjected to the rheological properties of the mix,similar total compaction energy delivered at different rate of compactional energy showed different degree of segregation(Figure 1).
Furthermore,segregation is analyzed using two separate approaches,i.e.point counting approach and image processing[5,7].These approaches are further explored for determining LWA shift pattern to quantify segregation.Results of this study can be applied for developing a better understanding and control mechanism for segregation.
Figure 1 Experimental methodology for the study