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There is a scarcity of natural river sand due to the ban on mining of sand from riverbeds, attributed to environmental and ecological issues. Therefore, there are attempts to use nonorganic solid wastes and industrial by-products as sand substitutes. The paper reports experimental studies on the suitability of processed granulated blast furnace slag (PGBS) as fine aggregate in the mortars used in masonry construction. The physical and chemical characteristics of the PGBS and the properties of mortars made with PGBS, such as workability, compressive strength, water retentivity, drying shrinkage, and elastic properties, were examined. The masonry properties such as compressive strength, flexure bond strength, and stress-strain characteristics were investigated using PGBS- and sand-based mortars. The investigations show that PGBS can be a potential substitute to river sand in the masonry application. The addition of PGBS was beneficial in terms of mortar and masonry characteristics. In the case of lean mortars, the addition of PGBS showed 30% to 45% spike in compressive strength. Thermogravimetry was used to quantify hydration products formed in PGBS-based and river sand–based mortars. The experimental outcomes indicate that (1) the physical and chemical properties of PGBS were similar to those of river sand except that the PGBS may show mild pozzolanic activity and higher water absorption; and (2) the masonry compressive strength increased by ∼22% , and the flexure bond strength nearly doubled when PGBS-based mortars were used. [ABSTRACT FROM AUTHOR]

On a global scale, buildings are responsible for significant energy consumption. While the energy intake of urban buildings has been studied well, there are barely any studies on rural dwellings. The current paper examines the embodied energy (EE), operational energy (OE) and life-cycle energy (LCE) of 27 rural dwellings spread across four climate zones of India. It is found that these rural dwellings use locally available least-processed natural materials with very low EE. However, with the advent of modern transportation, manufactured energy-intensive construction materials have reached rural areas. From the analysis it is seen that the EE ranges from 0.002 to 2.8 GJ/m2, the annual OE from 0.006 to 0.053 GJ/m2 and the LCE from 0.77 to 4.05 GJ/m2 for the rural dwellings studied, with mass ranging from 1.13 to 3.6 t/m2. [ABSTRACT FROM AUTHOR]

Construction industry consumes natural resources in bulk quantities for various products such as bricks/ blocks, mortar, concrete, etc. Indiscriminate exploitation of natural resources to meet the ever-expanding needs of the construction sector is posing serious environmental concerns and resulting in scarcity of natural raw materials. At the same time, a large volume of non-organic solid waste (NOSW) is being generated through various anthropogenic activities. It is challenging to find environmentally safe and economically viable solutions for handling such waste materials. This article discusses the construction industry scenario in India, some estimates of NOSW and strategies for their utilization. Few case studies of R&D work on the possibilities of utilizing NOSW for construction products are illustrated. In particular, the technical feasibility of utilizing construction and demolition (C&D) waste and iron ore tailings (IOT) as raw materials for construction products is highlighted. Experimental results presented here on the properties of mortar and concrete when C&D waste and IOT are used as an alternative to fine aggregate for replacing the scarce river sand are promising, showing immense potential for utilizing NOSW for the manufacture of construction products and materials. [ABSTRACT FROM AUTHOR]

The article presents an experimental investigation on the characteristics of fly ash-lime-gypsum bricks and their masonry. Topics discussed include examination of the strength, absorption and durability of compacted fly ash, as well as a review of the existing literature on fly ash bricks. Also mentioned are results on achieving compressive strength in saturated state, production of fly ash bricks of higher density, and fly ash brick showing higher flexure bond strength versus burnt clay brick.

A rammed-earth wall is a monolithic construction made by compacting processed soil in progressive layers in a rigid formwork. There is a growing interest in using this low-embodied-carbon building material in buildings. The paper investigates the strength and structural behavior of story-high cement-stabilized rammed-earth (CSRE) walls, reviews literature on the strength of CSRE, and discusses results of the compressive strength of CSRE prisms, wallettes, and story-high walls. The strength of the story-high wall was compared with the strength of wallettes and prisms. There is a nearly 30% reduction in strength as the height-to-thickness ratio increases from about 5 to 20. The ultimate compressive strength of CSRE walls predicted using the tangent modulus theory is in close agreement with the experimental values. The shear failures noticed in the story-high walls resemble the shear failures of short-height prism and wallette specimens. The paper ends with a discussion of structural design and characteristic compressive strength of CSRE walls. [ABSTRACT FROM AUTHOR]

This paper focuses on certain issues pertaining to energy, carbon emissions and sustainability of building construction with particular reference to the Indian construction industry. Use of sustainable natural materials in the past, related durability issues, and the implications of currently used energy-intensive materials on carbon emissions and sustainability are discussed. Some statistics on the Indian construction sector regarding materials produced in bulk quantities and the energy implications are discussed. Examples of low embodied energy materials are provided. An analysis of total embodied energy in conventional and alternative building systems shows nearly 50% reduction in embodied energy of buildings. Potential uses for solid wastes for building materials are presented. [ABSTRACT FROM PUBLISHER]

Soil-cement blocks are used for the load bearing masonry of 2–3-story buildings. Flexural and shear strength of such walls greatly depend upon the bond strength between the block and the mortar. This paper deals with the methods of improving the shear-bond strength of soil-cement block masonry (without altering the mortar characteristics) and the influence of shear-bond strength on masonry compressive strength. Altering the texture of bed faces of the block, size and area of the frog, and certain surface coatings have been attempted to enhance the shear-bond strength. The results indicate that: (1) rough textured bed face of the blocks yields higher shear-bond strength than the plain surface; (2) use of fresh cement-slurry coating on the bed faces improves the shear-bond strength considerably; (3) no significant changes are noticed in the compressive strength and stress-strain characteristics of soil-cement block masonry due to changes in shear-bond strength; and (4) masonry has a higher straining capacity than that of the block and the mortar. [ABSTRACT FROM AUTHOR]

Large numbers of soil-cement block masonry buildings exist in India and many other countries. The paper deals with an experimental study on the influence of soil grading on the characteristics of soil-cement blocks and shear-bond strength of soil-cement block masonry triplets. Influence of clay content of the soil-cement block on strength, absorption and durability characteristics, and interfacial mortar-block bond strength has been examined. Some of the major conclusions of the study are: (1) optimum clay content leading to maximum strength is in the range of 14–16%; (2) saturated water content of the blocks increases with increase in clay content of the block; (3) initial rate of absorption decreases with increase in clay content of the block; (4) weight loss after ASTM wire scratch test is minimum when the clay content of the block is about 16%; and (5) optimum clay content for the highest modulus for the blocks and for highest shear-bond strength is about 16%. [ABSTRACT FROM AUTHOR]

The research presented in this paper is aimed at developing novel alternative sustainable stabilized earth materials for use in load-bearing affordable housing construction. Prototype-stabilized earth materials have been produced in the laboratory, incorporating a range of solid wastes, including aggregates derived from construction and demolition waste as well as industrial processes. The earth construction materials were stabilized with either portland cement, Portland cement and lime, or through alkali activation. Experimental results for compressive strength are reported, together with findings from a comparative life cycle inventory analysis. Construction and demolition waste shows promise as a potential aggregate for stabilized earth construction. The use of processed ground blast furnace slag together with fly ash is also promising for the development of alkali-activated stabilization. [ABSTRACT FROM AUTHOR]