BITS Faculty Publications
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Item Characterization of Materials(Springer, 2024-02) Pradhan, Subhasis; Barai, Sudhir KumarConcrete is a composite material and a heterogeneous mixture of cement, coarse aggregate, fine aggregate, water, and chemical admixture. The behaviour and performance of concrete in the fresh as well as hardened stages largely depend on the physical, mechanical, and chemical properties of its constituents. Hence, it is important to determine the characteristics of the raw materials prior to the designing of concrete mix for their intended application. This book aims to compare the performance of concrete, prepared using two different types of coarse aggregates (natural coarse aggregate (NCA) and recycled coarse aggregate (RCA)). The subsequent sections exclusively discuss the differences in physical and mechanical properties between NCA and RCA.Item Macro-level Performance Assessment of Concrete: Experimental Fracture Analysis(Springer, 2024-02) Pradhan, Subhasis; Barai, Sudhir KumarNatural coarse aggregate (NCA) can potentially be replaced with recycled coarse aggregate (RCA), which is derived from the leftover concrete from construction and demolition (C &D) projects. However, RCA has drawbacks of its own, notably because of the porous mortar layer and micro-cracks. This motivates academics throughout the world to reduce the impact of the RCA’s inherent drawbacks in recycled aggregate concrete (RAC). Different mix design techniques, mixing procedures, the addition of fibres, and the addition of mineral admixtures are suggested in this context.Item Performance of reinforced recycled aggregate concrete beams in flexure: experimental and critical comparative analysis(RILEM, 2018) Barai, Sudhir Kumar; Pradhan, SubhasisThe necessity of sustainable approaches in the construction sector persuades the researchers to utilize the recycled coarse aggregate (RCA) extracted from waste concrete and study the performance of structural members by substituting natural coarse aggregate (NCA) with the RCA. In the present context, the flexural performance of RAC beam was examined on fourteen numbers of beams by completely replacing the NCA with RCA and using four different longitudinal reinforcement ratios (ρ) of 1.61, 1.31, 0.75 and 0.42%. In order to improve the quality of RAC, the particle packing method (PPM) of mix design approach was employed along with the two stage mixing approach (TSMA). The improved mechanical properties owing to the combined effect of PPM design mix and TSMA are also translated in the flexural performance of RAC beams even at 100% use of RCA. A maximum reduction of 35, 4 and 5% in cracking load, yield load and ultimate load, respectively, are observed in RAC beams as compared to the conventional concrete beams. However, the undesirable shear tension mode of failure was witnessed for RAC beams at ρ = 1.61%. A database is prepared by compiling the reported experimental results of RAC beams with shear reinforcement in the available literature. The suitability of the existing expressions to predict the ultimate load is verified for RAC beams and it is observed that, the number of unconservative predictions is significant. In this scenario, an equation is proposed to predict the ultimate load of transversely reinforced RAC beams by operating the flexure database, which shows good correlation with the available experimental results. Further, the increment in shear strength of RAC beams due to the inclusion of stirrups is estimated by using the derived expression.