Advances in Sustainable Construction Materials by Unknown

Advances in Sustainable Construction Materials by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9789811533617
Publisher: Springer Singapore


1 Introduction

The construction industry in India is booming. Already at 10% of the GDP, it has been growing at an annual rate of 10% over the last ten years as against the world average of 5.5% per annum. The built-up area is expected to swell almost five times from 21 billion sq. ft. in 2005 to approximately 104 billion sq. ft. by 2030. Buildings are at the core of all our demands water, energy and material, but they also create waste. This waste, generated in the construction, maintenance and disposal phases of a building, is called construction and demolition (C&D) waste.

As per the estimates of Centre for Science and Environment (CSE), since 2005, India has newly constructed 5.75 billion sq. m of additional floor space with almost one billion sq. m in 2013 itself. If (according to the Technology Information, Forecasting and Assessment Council’s, or TIFAC’s, thumb rule) a new construction generates 40–60 kg of C&D waste per sq. m, then taking an average of 50 kg per sq. m, India must have generated 50 million tonne(MT) of C&D waste in 2013. Over the last eight years, it would have produced 287 MT of this waste.

The use of C&D waste as recycled aggregates in concrete provides a sustainable solution for waste management and utilisation of natural resources. While countries like Belgium have been able to utilise C&D waste, India lacks a formal policy or mandate for its reuse. Tripathi et al. [1] in their attempt of promoting use of C&D waste observed that building sector needs to realise the viability of recycled concrete for the effective utilisation of C&D waste. This becomes a challenge when the studies carried out by previous researchers [2–7] have shown that use of recycled aggregates in concrete leads to reduced mechanical and durability properties.

Aldred et al. [2] reported that using hydrophobic admixture in dried concrete, water permeability reduced up to 77% to the control concrete. They noticed that by using hydrophobic admixture with 0.6 w/c ratio, initially saturated and dried cubes reduced water transportation. Eguchi et al. [3] reported that the production of recycled aggregates is very simple in present conditions. The compressive strength and modulus of elasticity were reduced on the increasing ratio of recycled aggregates in concrete. Debieb et al. [4] in their study reported that the physical properties of recycled aggregates played an important role in concrete properties. The durability may reduce due to high water absorption capacity and high porosity. Ning et al. [5] conducted studies on concrete protection by silane hydrophobic agents, utilising different concentrations and different agents for surface treatments. Water absorption capacity of concrete reduced on increasing the concentration of hydrophobic agents. Zhu et al. [6] reported that mechanical and physical properties reduced due to the replacement of recycled aggregate with natural aggregates. Water absorption reduced by surface-based treatment, and their effectiveness depends on numbers of coats and their concentrations. The compressive strength of sample decreased with increased dose of silane for mixing-based treated recycled concrete. Matias et al.



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