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A series of laboratory model tests have been carried out to examine the behavior of non-encased and geogrid encased conventional aggregate column (CAC) and fly ash brick bats column (FAC) resting on soft clay soil. In the present study, a series of load tests were carried out in a circular model tank of size 300 mm diameter and 400 mm height on soft clay soil with one, two and three columns of conventional aggregate (CA) and fly ash brick bats (FA). The experimental variables fixed in this study were aggregate type (CA and FA), encasement depth (non-encased, partially encased and fully encased), different length to diameter (l/d) ratio (8 and 10) and diameter of columns (30 mm and 40 mm). Based on the experimental results, it was seen that CAC have higher load capacity than FAC and the improvement was 2.72 times greater than untreated soft soil. The fully encased geogrid CAC possess higher load carrying capacity and the order of improvement was 3.63 times larger than untreated soft soil. In addition to that the load capacity of CAC and FAC increased with increasing the l/d ratio and diameter of CAC and FAC. The 40 mm diameter FAC possesses higher load capacity and the load capacity improvement was identified as 1.12 times greater than 30 mm diameter FAC. Further, the experimental results were validated by numerical analysis.

Population explosion, changing lifestyles, and a lack of housing facilities have created an acute shortage of affordable housing all over the globe. This essential part of the infrastructure of a country has put pressure on several governments to come up with new decisions to boost the rate of construction. UN Habitat (2016) emphasized this need, as only 13% of the cities in the world have sufficient affordable housing. Encouraging local authorities to work on some advanced techniques and alternative building typology with locally available resources could resolve this problem and simultaneously avoid depletion of natural resources. The present study deals with the development of alkali-activated bricks using co-fired blended ash, an industrial waste. As a preliminary study, the benefits of tailoring construction materials for large-scale housing construction using locally available wastes have been demonstrated. Physico-mechanical, thermal, and durability properties of the developed bricks were evaluated. As compared to a fly ash brick, the developed alkali-activated brick is 11% light in weight, which has 56% higher compressive strength and 62% lower thermal conductivity. Techno-economic aspect was evaluated with respect to long-lasting product optimization and modularization. The viability of the brick was evaluated and optimized using a slum housing project in Nagpur, India, by the computational method. The study resulted 7% cost reduction, 21% reduction in embodied energy, and 17% reduction in operational energy over the existing practice of construction. These statistics emphasize the strategy for energy conservation and low-cost housing construction.

Low-dimensional nanomaterials such as graphene can be used as a reinforcing agent in building materials to enhance the strength and durability. Common building materials burnt red soil bricks and fly ash bricks were reinforced with various amounts of graphene, and the effect of graphene on the strength of these newly developed nanocomposites was studied. The fly ash brick nanocomposite samples were cured as per their standard curing time, and the burnt red soil brick nanocomposite samples were merely dried in the sun instead of being subjected to the traditional heat treatment for days to achieve sufficient strength. The water absorption ability of the fly ash bricks was also discussed. The compressive strength of all of the graphene-reinforced nanocomposite samples was tested, along with that of some standard (without graphene) composite samples with the same dimensions, to evaluate the effects of the addition of various amounts of graphene on the compressive strength of the bricks.

The ambient gamma radiation around the Bellary thermal power plant was measured by Scintillometer of NaI (Tl) detector. The ambient gamma radiation level is mainly dependent upon the activity of primordial radionuclides present in soil and building materials. The activity of natural radionuclides presents in the soil and building materials of some villages around the Bellary thermal power plant is labelled by gamma-ray spectroscopy. The activity of natural radionuclides in soil such as 226Ra, 232Th and 40K varies from 24 to 86.2 Bq·kg−1, 45 to 115 Bq·kg−1 and 145 to 910 Bq·kg−1 with a mean value of 32.5, 79 and 640 Bq·kg−1, respectively. The total measured annual effective dose rate of gamma varies from 0.85 to 1.37 mSv·year−1 and the total calculated annual effective dose rate varies from 0.88 to 1.47 with a mean value of 1.18 mSv·year−1. The measured and calculated values of ambient gamma radiation are very nearer to each other and show positive correlation with a correlation coefficient of 0.44. All the measured radiological indices in soil and building materials are lower than the safe level limit except fly ash bricks, fly ash brick shows a value higher than the safe level limit. The fly ash emitted from the thermal power plant enhances the radiation level in nearby villages. The results are presented and analyzed in this paper.

Past experimental studies have shown that fly ash bricks are softer and weaker in comparison with burnt clay bricks and mortar generally used on site. Thus, mechanics of masonry under compression is altered such that the softer bricks are under tri-axial compression and mortar is under bilateral tension. An experimental study was carried out to understand the lateral load response of reinforced concrete (RC) frame infilled with fly ash brick masonry. Results showed that the frame provided reasonably good results in terms of lateral strength, stiffness, deformation, and energy dissipation. Using an analytical model developed from the experimental results a parametric study was carried out to compare the influence of using both fly ash and burnt clay brick masonry as infill in RC frames. Though frames infilled with fly ash brick masonry exhibited slightly lesser lateral strength and stiffness, the degradation in lateral load carrying capacity in post peak regime was significantly more gradual due to soft nature of fly ash bricks. Finally, to understand the possible reasons for the weak and soft nature of fly ash bricks, three types of analyses were carried out to evaluate their chemical and mineralogical composition: X-ray fluorescence analysis, scanning electron microscope associated with energy dispersive spectrometer, and powder X-ray diffraction technique. It was concluded that due to incomplete pozzolanic reaction, fly ash bricks exhibited weak and soft nature. Addition of activators was recommended to improve their stiffness and compressive strength, in case it is required.

China has ranked first in the coal fly ash emission in the world. The multipurpose use of the fly ash from power plant waste is always an important topic for the Chinese environmental protection, which has drawn the concern of the government, scientific research departments, manufacturing enterprises and industry experts. This paper introduces an experimental research on how to recycle fly ash effectively, a kind of new technology of making bricks by which fly ash content could be amounted to 50–80 %. The article introduces raw materials of fly ash brick, production process and key control points. It introduces how to change the technical parameters of the existing brick-making mechanical device, optimize the parameters combination and improve the device performance. High-content fly ash bricks are manufactured, which selects wet fly ash from power plants, adding aggregate with reasonable ratio and additives with reasonable dosage, and do the experimental research on manufactured products for properties, production technology and selection about technology parameters of production equipment. All indexes of strength grade, freezing-thawing resisting, and other standards of the studied bricks reached the national standards for building materials industry.

Lime–fly ash mixtures are exploited for the manufacture of fly ash bricks finding applications in load bearing masonry. Lime–pozzolana reactions take place at a slow pace under ambient temperature conditions and hence very long curing durations are required to achieve meaningful strength values. The present investigation examines the improvements in strength development in lime–fly ash compacts through low temperature steam curing and use of additives like gypsum. Results of density–strength–moulding water content relationships, influence of lime–fly ash ratio, steam curing and role of gypsum on strength development, and characteristics of compacted lime–fly ash–gypsum bricks have been discussed. The test results reveal that (a) strength increases with increase in density irrespective of lime content, type of curing and moulding water content, (b) optimum lime–fly ash ratio yielding maximum strength is about 0.75 in the normal curing conditions, (c) 24 h of steam curing (at 80°C) is sufficient to achieve nearly possible maximum strength, (d) optimum gypsum content yielding maximum compressive strength is at 2%, (e) with gypsum additive it is possible to obtain lime–fly ash bricks or blocks having sufficient strength (>10 MPa) at 28 days of normal wet burlap curing.