Feasibility Studies on Demolition Recycled Fine Aggregate and Sea Sand as Partial Preplacement to Natural Fine Aggregate in Concrete

In this research work, an attempt is being made to partially replace the natural fine aggregate with sea sand and recycled fine aggregate obtained from demolished concrete waste in varied proportions to concrete mix and subject the specimens to mechanical strength tests for short and long durations of 7, 28, 56 and 90 days curing. The compressive strength, split tensile strength and flexural strength results of 30% mix proportion (15% Sea sand + 15% demolished waste sand) were found to be 58.3 N/mm2, 3.53 N/mm2 and 4.71N/mm2 respectively. All the three strength test results obtained were found to yield 15% higher strength than the control specimens. Finally, it can be concluded that partial replacement of natural fine aggregate by sea sand and demolition recycled fine aggregate in construction industry, not only eliminates the waste management problems and impacts on environment, but also leads to the sustainable development by reducing the consumption of natural resources.

Effect of Bay Spacing on Design Parameters of RC Structures Subjected to Lateral Loads

Structural configuration is one of the important parameters to control the performance of multi-storeyed structures subjected to lateral loads. On other hand, also the economy of multi-storeyed structures depends on the spacing of columns. The present investigation is aiming to find the effect of bay spacing on the performance of medium to high rise RC structures subjected to lateral loads. In this regard, a computer- based analysis is carried out for 10, 15, 20, 25 and 30 storied bare frame structures. Each structure performance under lateral loads is investigated for 4 types of bay spacing i.e. 5m, 6m, 7.2m and 8.64m, with an increment of 20% bay space each time. For each structural model, the behaviour of the structure is examined in terms of storey displacement, storey drift and base shear. The quantitative parametric comparison is done between all the models mentioned and has identified the optimal size of the bay spacing to suit the aspect ratio of the structure is proposed.