Sanket Nayak

Bio: Sanket Nayak is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topics: Masonry & Unreinforced masonry building. The author has an hindex of 12, co-authored 27 publications receiving 613 citations. Previous affiliations of Sanket Nayak include Indian Institute of Technology Bhubaneswar & Indian Institute of Technology Dhanbad.

A critical review of retrofitting methods for unreinforced masonry structures

Abstract: Unreinforced masonry (URM) buildings are common throughout Latin America, the Himalayan region, Eastern Europe, Indian subcontinent and other parts of Asia. It has been observed that these buildings cannot withstand the lateral loads imposed by an earthquake and often fails, in a brittle manner. Methods for retrofitting URM buildings to increase the time required for collapse and also to improve the overall strength widely vary. This review has collated information on various types of retrofitting methods either under research or early implementation. Furthermore, these methods are categorized and critically analyzed to help further understand which methods are most suitable for future research or application in developing countries. The comparison of the different methods is based on economy, sustainability and buildability and provides a useful insight. The study may provide useful guidance to policy makers, planners, designers, architects and engineers in choosing a suitable retrofitting methodology.

Properties of recycled concrete aggregate and their influence in new concrete production

Abstract: This manuscript presents a review of the potential and challenge of using recycled concrete aggregate (RCA) as the substitute for natural aggregate (NA) in concrete mixtures. Using RCA in concrete preserves the environment by reducing the need for opening new aggregate quarries and decreases the amount of construction waste that goes into landfill. The properties of RCA such as specific gravity, absorption, and the amount of contaminant present in it contribute to the strength and durability of concrete. The quality of RCA depends on the features of the original aggregate and the condition of the demolished concrete. Some researchers have reported that the use of RCA degrades concrete properties while others have successfully produced RCA concrete with a performance that matched normal concrete (NC). In addition to the influence of RCA to concrete properties, this paper also evaluates multiple techniques to improve the performance of RCA concrete, reported cost savings in concrete production and recommendations regarding the application of RCA in concrete.

Strength and durability of concrete containing recycled concrete aggregates

Abstract: Recycled concrete aggregates (RCA) sourced from waste concrete are a sustainable alternative to natural crushed stone aggregates. The strength and durability properties of concrete containing RCA were evaluated by a comprehensive experimental investigation involving nine control mixes. The variables considered in the experimental study are water cement ratio, cement content in concrete and percentage replacement of coarse aggregate. The strength properties such as compressive strength, modulus of elasticity, splitting tensile strength and flexural strength are studied. Durability properties such as water absorption, sorptivity, acid attack resistance and chloride permeability are also determined. The test results showed that up to 25% of natural crushed stone aggregates in concrete may be replaced with RCA, without significantly affecting the strength of concrete and that the partial replacement of natural aggregates with RCA can be recommended in areas of moderate exposure conditions. Mathematical models developed in the study can be used for the a priori prediction of the strength parameters of RCA concrete. A mix design methodology using the developed models is proposed to aid practicing engineers to determine the mix proportions of RCA concrete.