Architecture is both art and science; it is physical yet intangible; it is the buildings we build and it is also the assimilation of life, lifestyles, history, culture, evolution, creativity, desire, ambition - all rolled in one. Alongside humans, architecture too has evolved over centuries – adapting to geography, topography, climate, rain, snow, wind patterns, locally available materials, migration, human habits, cultural movements and in response to adverse natural events; resulting in unique methods of construction which fit the requirements and aesthetics of people from different regions. The solutions were therefore, also unique; and over time these responses became intuitive giving a diverse regional tone to the language of constructed spaces.
Concrete is the building block of modern society and the most widely used building material. There are several initiatives and stated goals to minimize the environmental impact of the built environment of construction. To remain competitive, the concrete industry needs to respond to the challenge and lead. The primary focus at this time is the reduction of the embodied carbon of a project when built. There are other initiatives that look at the operational phase of the built environment This paper discusses 10 possible strategies that can reduce the carbon footprint of concrete when there is a sustainability goal for a project. These strategies include more effectively addressing current technology and considering innovation to achieve these goals. These strategies take advantage of concrete’s benefits while ensuring the lowest possible carbon footprint.
Urbanization will dramatically increase in the coming decades; hence building and infrastructure construction will shoot up and will need to reinvent itself to address its main future challenges like productivity, building comfort or sustainability. Ready mix concrete will no doubt be the preferred material of the future supported by ground-breaking innovative solutions helping to reduce its CO2, natural mineral resources and water footprints to nearly zero, and to boost jobsite productivity and quality, possibly with 100% recycled raw materials concretes, fresh concretes on-demand, 3D-shotcreting, fully digital monitoring from A to Z or delivery drones, to name just a few.
This paper provides a literature review on the use of bottom ashes in the production of concrete with recycled aggregates. Three types of bottom ash were studied, namely: biomass bottom ashes, coal bottom ashes and sewage sludge bottom ash. The characterization of these ashes focused on the analysis of their physical, chemical, and mineralogical properties. The effect of these ashes was subsequently studied on the fresh, mechanical, and durability-related performances of concrete. Bottom ashes generally present lower pozzolanicity than that typically observed, for example, in coal fly ashes. Their use as partial cement replacement normally leads to some loss in performance of the resulting cementitious composites. Also, using them as aggregates or in combination with recycled aggregates of other sources similarly causes an overall loss in performance. Nevertheless, such decline is still acceptable and often within manageable limits for the production of concrete under specific conditions including some structural applications. The use of these by-products including recycled aggregates may assist in solving a two-fold problem. Firstly, it reduces the consumption of cement and, consequently, the extraction of natural resources, also including the decrease of the consumption of natural aggregates to produce concrete. Furthermore, it solves the problem of the final destination for the significant quantities of bottom ashes produced by different industrial processes. In general, it is possible to conclude that, in moderate contents and when adequately processed, bottom ashes can be considered as viable substitutes of cement with manageable losses in terms of mechanical and durability-related performances. The use of coal bottom ashes was also found to significantly reduce the drying shrinkage strain of concrete.
Since the last few decades, chemical admixtures have become an integral part of cement concrete produced at concrete batching plants in India. However, during concrete applications the way we utilize admixtures in India, we are unable to realize their full potential compared to developed nations. Most of the admixtures utilized in India belong to the water reducing and retarding family and are used for water reduction and workability retention of concrete. The use of durability enhancing admixtures, value added admixtures and specialty admixtures in concrete is picking up but is relatively less compared to the developed countries. This paper focuses on the current way chemical admixtures are utilized in India, the challenges, prevalent technologies but which are not regularly used in India and a few innovative technologies which may be used in the future.
Prescriptive durability provisions have been used worldwide for designing concrete structures. Such structures are found to have deteriorated prematurely (unpredicted and suddenly), requiring expensive repairs. In this paper a probabilistic life-cycle deterioration analysis is performed for an upcoming coastal reinforced concrete bridge in India to proactively estimate the time of its first repair. This information is of utmost importance, particularly to support bridge managers defining the budget allocations for maintenance scenarios. This analysis also highlights the inadequacy of the current prescriptive provisions and the importance of adopting the probabilistic durability design for new infrastructures in the future.
