Recycled Concrete Aggregate in Construction Part II

Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.

1. USE OF RCA for construction CIVIL ENGINEERING DEPARTMENT ADITYA RANJAN PATRA ( TRANSPORTATION ENGINEERING)

2. Contents: Introduction What is recycled concrete aggregate Sources of Recycled aggregate PROPERTIES OF RECYCLED CONCRETE AGGREGATE Process of recycled concrete aggregate Advantages & disadvantages of recycled concrete aggregate Conclusions references

3. INTRODUCTION: To achieve sustainable issue in construction area, researchers and companies focus on using waste concrete as a new construction material. It is called recycled aggregate which can be produced by concrete crusher. The aggregates are categorized by size as coarse and fine aggregate.

4. What is recycled concrete aggregate ? R ecycled concrete aggregate has a proportional mortar which attached to aggregate, it gives a higher porosity and a lower strength to RAC than the normal concrete. In addition, since recycled aggregates require more amount of water than natural aggregate, shrinkage issue could be a problematic to use RAC practically. It has a lower density, elastic modulus, strength and a higher water absorption capacity.

5. The enormous quantities of demolished concrete are available at various construction sites. Many old buildings, concrete pavement ,bridges and other structures have overcome their age and limit of use due to structural deterioration beyond repair and need to be demolished. The structures, even adequate to use are under demolition because they are not serving the needs in present scenario. Structures are turned into debris resulting from natural disasters like earthquake, cyclone and floods etc. SOURCEs OF AGGREGATE :

6. PROPERTIES OF RECYCLED AGGREGATE Particle size distribution Specific gravity Water absorption Compressive strength

7. PROCESS : For the production of the RC without impurity in the required gradation, a production plant has to be used. This can either be stationary or mobile. However, both consist of the same setup which includes separation, crushing, separation and removal of ferrous elements, screening, decontamination and removal of impurities.

8. Breaking up and removing the old concrete. Crushing separation of aggregates

9. Advantages: Save environment Save energy Reduce cost Reduce the demand of natural aggregate. Disadvantages: Lack of specification and guidelines. Less quality as it is a waste material. Benefits: Using recycled material as gravel reduces the need for gravel mining. Using recycled concrete as the base material for roadways reduces the pollution involved in trucking material.

10. The physical properties of recycled aggregates make them ideally suited for road base and sub-base. This is because of their physical properties which means less cement is require making them suited for sub-base use. This is in addition to the cost benefits accrued by developers in the process. Recycle & reuse is an appropriate solution to problems of dumping hundred of thousands of tons of demolition wastes. However more research and initiation of project for application of RCA is started for modifying design codes, Specifications & procedure for use of RCA. Conclusions:

11. R EFERENCES: Parekh D. N. and Dr. Modhera C. D., “Assessment of recycled aggregate concrete”, Volume II, Issue 1, pp. 1-9, March 2011. Jitender Sharma, Sandeep Singla, “Study of Recycled Concrete Aggregates”, Volume 13, pp. 123-125, July 2014. RIMT-IET, Mandi Gobindgarh , PTU, India. Animesh Awasthi, Gourav Soni , Ram Bharosh , “Study of Recycled Aggregate Concrete as Partial Replacement for Cement”, Volume 4, Issue 2, pp. 239-245, 2018. https://www.slideshare.net/neelanjan06/recycled-aggregate-concrete https://www.researchgate.net/publication/222515274_Recycled_concrete_aggregates https://www.sciencedirect.com/science/article/pii/S2352710221000528