Fly Ash Lime Gypsum Research Articles

On the use of flyash-lime-gypsum (FaLG) bricks in the storage facilities for low level nuclear waste

In the present study, radiation shielding and protection ability of prepared Flyash-lime-Gypsum (FaLG) bricks has been studied in terms of energy exposure build up factors and dose parameters. The energy exposure build up factors of Flyash-lime-Gypsum (FaLG) bricks have been calculated for the energy range of 0.015 MeV–15 MeV and for penetration depth upto 40 mfp directly using a new and simplified Piecewise Linear Spline Interpolation Method (PLSIM). In this new method, the calculations of G.P fitting parameters are not required. The verification and accuracy of this new method has been checked by comparing the results of exposure build up factor for NBS concrete calculated using present method with the results obtained by using G.P fitting method. Further, the relative dose distribution and reduced exposure dose rate for various radioactive isotopes without any shielding material and with Flyash-lime-Gypsum (FaLG) bricks have been calculated in the energy range of 59.59–1332 keV. On the basis of the obtained results, it has been reported that the prepared Flyash-lime-Gypsum (FaLG) bricks possess satisfactory radiation shielding properties and can be used as environmentally safe storage facilities for low level nuclear waste.

Properties of Lime Mortar and FAL-G with Urea

In traditional Indian lime mortar preparation, urine is added to improve the properties. In this research instead of urine, urea (fertilizer)is tried to give a sanitarily viable alternative. Urea is added in the various viz. 1%, 2%, 3%, 4%, 5% with Lime mortar 1:3 and also Fly Ash Lime Gypsum (FAL-G) paste. The resultant composites were cast into cubes of 50 sq.cm area and tested for weight density, water absorption and compressive strength. Results were compared with plain lime mortar cubes and plain FAL-G cubes. FAL-G shows better properties with 3% urea than lime mortar.

Infiltration and clogging characteristics of pervious concrete

Pervious concrete is essentially used to reduce stormwater runoff and local floods. It requires regular maintenance because it is highly prone to clogging by particulate matters. Clogging is defined as a reduction in hydraulic conductivity that drastically reduces the permeability into the subgrade. A study using permeability as a key parameter was carried out to measure the infiltration characteristics of pervious concrete containing various binders and different sizes of coarse aggregates namely 6.3 mm, 8 mm, 10 mm and 12.5 mm. The binders such as Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC), Fly ash based Geopolymer (GP) and Fly ash—Lime-Gypsum (FaL-G) were used. The results indicated that pervious concrete made with aforesaid binders showcased adequate infiltration properties that satisfied the requirements of pervious concrete. Furthermore, clogging effect study was performed in GP binder pervious concrete by applying flowing water containing mud to determine worst-case scenario percentage for clogging. The worst-case silt percentage in water to cause clogging was found to be 8.26%, 9.21%, 9.84% and 10.16%. The test results indicated that increasing of clogging material in the water significantly reduces the permeability.

A probabilistic approach for identification of compressive strength of fly ash bricks

In the present industrial scenario, the production of fly ash being a waste from thermal power plants is increasing at an alarming rate. Fly ash not only creates a major problem at its disposal but also causes other environmental/health-related issues. To combat this waste is to find its application in the construction sector. In the past, fly ash is recognized as a promising replacement of clay in brick industry. The aim of the present work is to determine the characteristic compressive strength in a probabilistic approach for the Fal-G (fly ash–lime–gypsum) bricks constitutes the consumption of two waste products (fly ash and sludge lime) in brick manufacturing. For casting of Fal-G bricks, a semiautomatic, hydraulic operated brick manufacturing machine is fabricated and the compressive strength of the compacted bricks is observed. However, the compressive strength of the resulted bricks observed to be quite satisfied with the minimum value recommended as per IS 12894-1990. The study is further extended towards the fitting of randomly generated compressive strength values of Fal-G bricks to four different probability distribution functions and adopting Kolmogorov–Smirnov (KS) test to detect the best-fitted probability distribution of the present data. From the descriptive statistics of KS test results, it is inferred that the most common distribution, i.e. normal distribution, fits well to the data with the highest p value of 0.898. Normality test such as P–P and Q–Q plots is used to further confirm that the present data follow the normal distribution. Actual and expected z-scores are plotted to get all the data points on y = x line that follows the normal distribution. Determining the frequency factor of the normal distribution, the compressive strength is calculated at each probability level. At 95% probability level, the characteristic compressive strength of Fal-G bricks is obtained 4.8 N/mm2. Further, a curve fitting between a probability of exceedance and compressive strength shows logarithmic relationship which holds between the two variables with R2 = 0.932.

Out-of-plane flexure behaviour of fly ash-lime-gypsum brick masonry walls

Industrial by-products such as fly ash is being used for the manufacture of building products such as fly ash bricks. This paper is focused on understanding the out of plane flexural behaviour of fly ash-lime-gypsum (FaL-G) brick masonry, through experimental investigations. Results of the flexure strength of FaL-G brick masonry walls (under different pre-compression) in the two orthogonal directions, are discussed. Load displacement and moment-curvature relationships for the two cases presented. The cracking flexural stress using linear elastic analysis was predicted and compared with the experimental value. The results reveal that (a) the flexure strength of FaL-G brick masonry walls increases linearly with the increase in pre-compression, (b) the flexure strength parallel to bed joints is two times more than that of the flexure strength perpendicular to bed joints under zero pre-compression, (c) lateral displacements for the FaL-G brick masonry walls are larger for the case of bending perpendicular to bed joints when compared with those for bending parallel to bed joints and (d) The cracking flexural stress for the FaL-G brick masonry can be predicted closely with those of experimental values using linear elastic analysis.

Studies into structural and thermal properties of building envelope materials

The structural and thermal properties of masonry units influence the behaviour of masonry. In load bearing masonry, wall elements play a major role in supporting the structure through load transfer mechanism from roof to foundation. Also, wall elements regulate the thermal interaction between the indoor and outdoor environment. A variety of masonry units are available as an alternative to burnt clay brick masonry. Fly ash-Lime-Gypsum (FaL-G) brick is one such alternative, which is a low carbon and energy efficient brick made of industrial waste fly-ash. The current paper investigates the characteristic properties of FaL-G bricks and compares them with the locally available conventional table moulded brick (TMB). The characteristic results reveal that the FaL-G brick performs better as a masonry unit and also for building envelopes in tropical conditions. Based on investigations regarding structural and thermal performance, suitable guidelines can be issued to integrate this material in the building envelope.

Fal-G Binder Pervious Concrete

Pervious concrete can be described as a porous concrete which permits the penetration of water through the interconnected network of pores. In general, pervious concrete is produced using Ordinary Portland Cement (OPC) as binder, and being used for pedestrian path, parking lots and has many other applications. In this paper Fly ash-Lime-Gypsum (FaL-G) binder has been used as a binder and studies have been carried out for physical, mechanical and other relevant properties with various sizes of coarse aggregates. The results are compared with the pervious concrete made out of OPC binder. The test results are presented and discussed elaborately. It is found that FaL-G binder pervious concrete satisfies the requirements laid down by codal provisions.

Study on use of Industrial Waste in Preparation of Green Bricks

Background/Objectives: The present generation of fly ash in the country is about 90 million tonnes and quarry dust is about 65 million tonnes. The utilization of fly ash in cement and other related industries is less than 10%. Safe disposal of remaining fly-ash and quarry dust has become a challenging problem. It is therefore necessary to utilize fly-ash and quarry dust in structural elements. The most basic building material for construction of houses is the usual burnt clay brick. A significant quantity of fuel is utilized in making these bricks and the burning of these fossil fuels liberate green house gases which cause depletion of ozone layer. Also, continuous removal of topsoil, in producing conventional clay bricks, creates environmental problems. Methods/Statistical Analysis: A feasibility study was undertaken on Fly ash-Lime-Gypsum (FaL-G) bricks and Quarry dust-Fly ash-Lime-Gypsum (QuFaL-G) bricks to use as a building element. The bricks of size 220 x 100 x 75mm were casted to study the strength and durability characteristics. Results shows that the compressive strength of FaL-G bricks was 8.2 N/mm2 on the 28th day, which is much higher than the conventional burnt clay bricks (>3.5 N/mm2). Findings: The water absorption property of FaL-G brick is lesser than the water absorption of normal good quality burnt clay bricks (20%). Applications/Improvements: In view of the strength and durability characteristics of these bricks, it can be used in place where the fly ash and quarry dust available more in quantity to solve the consequences of pollution and at the same time to build houses economically by utilizing industrial wastes.

Effect of construction materials on embodied energy and cost of buildings—A case study of residential houses in India up to 60 m2 of plinth area

Worldwide buildings consume annually about 30–40% of primary energy in construction, operation and maintenance. An enormous part of this energy is consumed in construction activities alone. Nearly two million residential buildings for economic weaker section alone, are required to be built annually in India, apart from offices, commercial, public and industrial buildings. Use of low embodied energy and cost effective building materials, in the building construction, can significantly reduce the overall energy consumption and thus eventually minimize energy footprint of buildings. In this paper, the embodied energy and construction cost have been estimated for the residential houses (up to four storied) of a chosen typology. The calculation has been done for total 122 nos of houses, having plinth area varying between 20m2 and 60m2. The embodied energy and construction cost have been compared and analyzed for various building materials (i.e. burnt clay bricks, hollow cement concrete blocks, aerated autoclaved blocks, fly ash lime gypsum blocks, solid cement concrete blocks etc.). It is estimated, that the embodied energy (EBE) is least (2.092GJ/m2) for two storied houses, constructed with hollow cement concrete block based masonry, however cost of building materials is found to be lowest (US$ 62/m2) for four storied houses constructed with AAC block based masonry.

Simplified two media method: A modified approach for measuring linear attenuation coefficient of odd shaped archaeological samples of unknown thickness

Linear attenuation coefficients of regular as well as irregular shaped archaeological samples of FaLG (flyash–lime–gypsum) of unknown thickness have been measured employing ‘simplified two media’ method. Seven different liquid materials plus air have been used as media to measure attenuation coefficient of these samples. Obtained results have been compared with those for regular shaped samples. Experimental values have also been compared with theoretical values calculated from FFAST and XCOM. A good agreement has been observed between experimental and theoretical values. Present measurements employing ‘simplified two media’ method have been reported for the first time for checking its validation and reliability.

Unconfined Compressive Strength of Fly Ash–Lime–Gypsum Composite Mixed with Treated Tire Chips

The paper presents the potential and effect of treated tire chips on the unconfined compressive strength in the reference mix containing fly ash, lime, and gypsum. Dry, sodium hydroxide–, and carbon tetrachloride–treated tire chips were used in the study. The tire chip content varied from 5 to 15%. The specimen prepared was cured for 7, 28, 90, and 180 days with three different curing methods (in a dessicator, burlap, and water-filled container). The results indicated that the unconfined compressive strength of the reference mix with dry tire chips can be increased by treatment with carbon tetrachloride and sodium hydroxide. The increase in unconfined compressive strength was highest with carbon tetrachloride treatment. The results further revealed that the increase in unconfined compressive strength was highest when cured in water-filled container, followed by burlap and dessicator. The unconfined compressive strength increased with curing period, and the increase was significant up to a curing period of...

Effect of silica fume and expanded perlite addition on the technical properties of the fly ash–lime–gypsum mixture

The main objective of this research was to investigate the effect of different type of pozzolan additions to cement free lightweight block made from fly ash–lime–gypsum mixture and observe the changes in physical, mechanical, thermal properties and microstructure. Thermal conductivity of the fly ash–lime–gypsum mixture was improved by the addition of the expanded perlite. Optimal strength-thermal conductivity combination was obtained by the usage of silica fume and expanded perlite together. Improved strength properties were obtained by using hydrothermal curing conditions and superplasticizer addition.

A perspective study on fly ash–lime–gypsum bricks and hollow blocks for low cost housing development

Housing is a great problem in today's world. The most basic building material for construction of houses is the usual burnt clay brick. A significant quantity of fuel is utilized in making these bricks. Also, continuous removal of topsoil, in producing conventional bricks, creates environmental problems. A feasibility study was undertaken on the production of fly ash–lime–gypsum (FaL-G) bricks and hollow blocks to solve the problems of housing shortage and at the same time to build houses economically by utilizing industrial wastes. The compressive strength, water absorption, density and durability of these bricks and hollow blocks are investigated. It is observed that these bricks and hollow blocks have sufficient strength for their use in low cost housing development. Tests were also conducted to study the influence of type of curing on the increase in strength and hardening of the bricks and blocks with time. It was observed that the hot water curing leads to a greater degree of hardening and higher strength, earlier compared to ordinary water curing.