Including Fly Ash Research Articles

The Effects of Supplementary Cementitious Materials (SCMs) on the Residual Mechanical Properties of Concrete after Exposure to High Temperatures—Review

Fire events remain a severe hazard despite significant progress in the construction industry. The high-temperature resistance of concrete structures highly depends on the properties of their ingredients. The present study provides an analytical review of the available experimental studies investigating the influence of high temperatures on the residual mechanical characteristics of concrete, namely compressive and tensile strength, as well as the modulus of elasticity. This paper primarily focuses on the influences of supplementary cementing materials, including silica fume (SF), fly ash (FA), and ground granulated blast furnace slag (GGBFS), as well as different aggregate types. The literature findings show that the mechanical characteristics of concrete are degraded dramatically due to heat-caused changes in concrete. In addition, the mechanical properties of concrete are highly influenced by the types of aggregate and the amount of supplementary cementing materials at both high temperatures and room temperature. The inclusion of FA and GGBFS improves the high-temperature resistance of concrete. However, high contents of FA and GGBFS result in adverse effects on the properties of concrete. This review will provide a basis for future studies and enhance the knowledge of the behaviour of reinforced concrete structures subjected to high temperatures.

Композиционные механоактивированные вяжущие на основе золы тепловой станции, кальцита и двуводного гипса

The paper presents the results of studying the binding properties of a mechanically activated composition including fly ash from the Apatity Thermal Power Plant with increased calcium content, calcite concentrate produced from apatite-carbonatite ores of the Kovdorsky deposit and natural gypsum stone. It was found that the composition, depending on the mixing ratio and curing conditions, displays characteristics of both hydraulic binder similar to lime-ash one and air binder similar to gypsum.

Study on the Physical and Chemical Properties of Cement-Based Grout Containing Coal-Fly Ash.

To study the physical and chemical properties of grout containing fly ash, Class II fly ash was used as a mineral admixture and mixed with silicate cement to produce grout, and the rheological properties, strength properties, hydration properties, and microscopic mechanism were studied. The results of the study showed the following. The incorporation of fly ash reduced the thixotropic area of the composite cement slurry, which facilitated pumping in the pipeline conveying process. The inclusion of fly ash reduced the yield stress and plastic viscosity of the cement paste, but the rheological index increased and then decreased with the increase in fly ash, and the composite paste had the lowest degree of shear thinning at 30% fly ash inclusion. The incorporation of fly ash reduced the hydration exothermic rate and total hydration exothermic amount of the composite slurry and prolonged the hydration induction period, but the promotion effect of fly ash on the hydration rate of cement was obvious at 10% fly ash admixture. The admixture of fly ash increased the empty volume of the composite slurry, but the effect on the most probable aperture was not significant, and the porosity of the system increased, resulting in a decrease in compressive strength. The effect of adding fly ash on the hydration products was reflected mainly by the C-S-H gel produced by cement hydration and the change in calcium alumina and Ca(OH)2. Fly ash does not directly participate in the hydration reaction of cement, but it can promote cement hydration and increase the reaction rate of cement. By analyzing the rheological properties, mechanical properties, and hydration properties of fly ash composite cement paste, the comprehensive analysis found that the rheological properties are excellent when the fly ash admixture is 20-30%, and the water-cement ratio can be reduced to improve the strength without affecting the pumping demand.

To Investigate the Mechanical Properties of Concrete by Partial Replacement of Cement with Ceramic Tiles Waste Powder and Addition of Jute Fiber

Abstract: The need for natural and non-renewable resources has grown as a result of the continuing development of society and human endeavours. As a result, the amount of industrial solid waste products kept growing. The most widely used man-made material in the world, concrete, has generated a lot of interest as a potential method for recycling solid waste. About the same amount of CO2 is produced during the manufacture of 1 tonne of Portland cement. The cement sector is thought to be responsible for 5% to 8% of yearly global greenhouse gas emissions. The use of waste materials in our current concrete can lessen the environmental pollution. Put the scenario in a critical state employing alternate approaches and come up with a better material recycling solution. As additional cementitious materials, a variety of by-products, including fly ash, slag, and silica fume, are successfully used every day in the manufacturing of concrete (SCM). According to the research it has been found that about 150 million tons of ceramic have been produced per year. From that total production, around 25% to 35% has become waste material without recycling from the ceramic industry at present. The ceramic powder has various advantages such as cost - saving, energy Saving and reduces the hazards materials to the environment. Ceramic waste can be used in concrete to increase the compressive strength and physical and chemical properties of concrete. It has been established that the addition of evenly distributed, tightly spaced Fibers to concrete will significantly enhance its static and dynamic properties and act as a crack arrester. Concrete that has been reinforced with fibrous material, or fiber-reinforced concrete (FRC), has a higher structural stability. It is important to note that jute is sometimes referred to as the golden fibre owing to its high cash value and its colour. It improves the shear and punching resistance of concrete, aid in recovering post-cracking strength losses, increases the toughness and become an effective way for reinforcement. In this experimental work, partial replacement of cement by ceramic tiles waste powder by percentages of 0%, 15%, 20%, 25% and 30% with expansion of Jute Fiber at different rate as 0%, 0.25%, 0.50%, 0.75% and 1.0% are done to make sustainable concrete. All specimens were cured for 7days and 28 days before testing. From the study it has been observed that the test results shows optimum proportion for concrete mix and are within acceptable limits.

Development of solid waste-based self-insulating material with high strength and low thermal conductivity

Foam concrete as a thermal insulation material has been widely used to meet building energy conservation requirements. In this study, a low-clinker foamed concrete was prepared with an amount of solid waste, including fly ash, carbide slag, and glauber's salt, up to 80%. The effect of polycarboxylate superplasticizers (PCs) in the preparation process was examined to improve the mechanical properties of this particular system. The characteristic of hydration products and the pore structure was analyzed to illuminate the PCs influence on the hydration process. The outcomes demonstrate that the PCs can effectively improve the slurry's fluidity, enhance its compressive strength, and decrease its average diameter. Low-clinker foamed concrete's compressive strength reached 5.3 MPa, and its thermal conductivity reached 0.1556 W/(m·K). It was concluded that foam concrete has the potential to be widely used in green buildings due to its high strength and low thermal conductivity.

Water quality implications of the neutralization of acid mine drainage with coal fly ash from India and the United States

Subsurface coal mining often induces the formation of acid mine drainage (AMD) in active and abandoned coal mines while coal combustion generates coal combustion residuals (CCR), including fly ash (FA), with elevated levels of toxic metals. Decades of AMD and CCR production have caused major environmental and human health impacts. Given the typically elevated level of oxides in FA, previous studies have examined its potential to neutralize AMD and remove the associated metals. While the neutralization of AMD through reaction with FA has been demonstrated to successfully remove cationic metals, the fate of oxyanion forming elements are less well studied and is the focus of this study. Here we conducted 49 different experiments in which simulated AMD solutions were interacted with representative U.S. (n = 7) and Indian (n = 6) FA samples through controlled liquid to solid ratios in short-term (24 h) and long-term (up to 5 weeks) lab-scale experiments. We show that Class-F FA, originating from Gondwana and Northeastern Tertiary coals in India, has limited neutralization capacity, while Class-C FA, with high CaO and MgO contents from Powder River coals in the U.S. has the greatest AMD neutralization capacity among the studied fly ashes. The neutralization experiments show that AMD-FA reactions cause the removal of cationic elements (i.e., Fe, Mn, and Al) from solution, while at the same time, leaching oxyanion forming elements (i.e., As, Se, Mo, Cr, B, Tl, and Sb) from the FA, increasing the potential environmental risks from the treated leachates. The magnitude of mobilization of these elements depends on their concentrations in the FA and the pH conditions. We show that using FA from the Appalachian and Illinois coals efficiently neutralizes AMD, but also results in secondary contamination of the treated effluents with oxyanion forming elements to levels exceeding drinking water and ecological standards, which could contaminate the ambient environment, whereas neuralization with Powder River Basin Class-C FA induces only limited contamination.

Feasibility Study of Grinding Circulating Fluidized Bed Ash as Cement Admixture

With the widespread application of circulating fluidized bed (CFB) combustion technology, the popularity of CFB ash (CFBA) has increased dramatically and its production and large-scale utilization have become increasingly important. In the context of carbon neutrality peaking, using CFBA as a cement admixture as an effective method of resource utilization not only reduces the pressures caused by carbon emissions in the cement industry but also solves the environmental problems caused by CFBA depositing. However, the formation conditions of CFBA are worse than those of traditional pulverized coal boilers. CFB ash is the combustion product of coal at 850 °C–950 °C, and the characteristics of CFBA usually include a loose and porous structure with many amorphous substances. Furthermore, it has the disadvantages of large particle size, high water-demand ratio, and low activity index when it is directly used as a cement admixture. In this study, CFBA (including fly ash (CFBFA) and bottom ash (CFBBA)) produced by a CFB boiler without furnace desulfurization with limestone was used as a cement admixture material, and the effect of grinding on the fineness, water-demand ratio, and activity index of CFBA were studied. The experimental results showed that the grinding effect could significantly reduce the fineness and water-demand ratio of CFBA as a cement mixture and improve the activity index. With the increase in the grinding time, the water-demand ratio of CFBA first decreased and then increased. CFBBA ground for 10 min and CFBFA ground for 4 min can reduce the water-demand ratio of CFBA by up to 105% and increase the compressive strength of 28-day-old CFBA cement by 7.05%. The grinding process can ensure that CFBA meets the Chinese standards for a cement admixture and realize the resource utilization of CFBA.

Roles of fly ash, granulated blast-furnace slag, and silica fume in long-term resistance to external sulfate attacks at atmospheric temperature

This paper presented the role of supplementary cementitious materials (SCMs), including fly ash (FA), granulated blast-furnace slag (GBFS), and silica fume (SF) in long-term resistance to external sulfate attack (ESA) of cement mortar at atmospheric temperature. The cement mortars were immersed in 5% sodium sulfate solution at a temperature of 20 °C for 36 months. The results showed that the amount of deterioration products and pore characteristics were the two critical factors affecting sulfate resistance. The pore characteristics played more integral roles in influencing the long-term sulfate resistance than the amount of deterioration products. FA maintained excellent sulfate resistance after exposure to ESA for 36 months. SF exhibited higher sulfate resistance than FA because it primarily supported total porosity and percentage of harmless pore, rather than the portlandite removal by the pozzolanic reaction. On the contrary, the addition of GBFS accelerated the deterioration process and exhibited the worst sulfate resistance because the total porosity and percentage of harmless pore occurred massive changes.

Investigation of Abrasion Test and Mechanical Properties of Concrete Using Fly Ash as A Partial Replacement of Cement

Abstract: Concrete is one of the most versatile and widely used material in the construction sector. With the development and advancements of concrete, Civil engineering has reached its technological pinnacle. Despite its global and excessive demands, the consumption of cement is increasing day by day which is to be managed. Also there are many challenges related to its consistent strength performance , Abrasion resistance, Durability etc. so there is a great need to overcome these problems by the application of a pozzolanic admixture known as Fly ash which is responsible for improving various mechanical properties of concrete such as Abrasion Resistance and strength aspects and also reducing the consumption of cement at the same time. In this experimental Work, the Inclusion of Fly Ash and its effect on the various mechanical properties of the concrete i.e. Abrasion resistance, compressive strength, split tensile strength and flexural strength etc is investigated. The present investigation is carried on M35 Grade concrete. Firstly, concrete mixes is prepared by using Ordinary Portland cement( OPC 53) as a reference concrete mix and then blended concrete mixes is prepared by partial replacement of cement using fly ash in range of 10%, 20%, 30%, 40%, 45% by the weight of cement. This experimental study is carried for Determining the differences in the various mechanical properties of blended concrete (Fly ash and cement) and conventional concrete. The optimum percentage of using fly ash with cement in the concrete mixes is determined. The various parameters studies of concrete investigated are Abrasion resistance , workability of freshly prepared concrete mixes, compressive strength at 7 and 28 days, split tensile strength at 28 days. All these tests on concrete mixes is to be performed for both conventional concrete mixes (using only OPC) and also with blended concrete mixes ( OPC and its partial replacements with fly ash).

Self-healing concrete: a potential smart material to apply for underground construction

The crack of the concrete in underground constructions is generally difficult to detect and repair and consequently causes structural deterioration. Smart concrete with self-healing ability to autonomously repair micro cracks is a potential smart material to apply for underground constructions with sustainable development proposes. This paper reviews healing materials, the self-healing process, and the mixing method of self-healing concretes using bacteria, mineral admixtures, and fibers. The bacteria such as Bacillus sphaericus, Bacillus megaterium, Bacillus subtilis, Bacillus pasteurii, and Bacillus subtilis can produce a calcareous product for healing exterior cracks through microbial metabolic processes. As micro cracks are formed in the smart concrete, the bacteria spores contact nutrients and water and generate Calcium Carbonate (CaCO3). The addition of mineral admixtures based on silica including fly ash and granulated blast furnace slag (GGBS) heals the inner cracks through Calcium silicate hydrate (CSH) gels ( hydration reaction products. Other minerals such as expansive materials, geo-materials, crystals, and chemical additives change their forms or volumes to close cracks. Fibers including steel, carbon, PVA, PE, and carbon fibers are utilized to develop self-healing concretes based on controlling the crack width. The addition of fibers generates multiple micro-cracks, decreases the crack width, and enhances autogenous crack healing. Besides, healing agents can be easily dispersed into self-healing concretes by using the dry mixing, the wet mixing, or the latter mixing. Hence, all smart concretes with self-healing ability demonstrate potential and suitable characteristics for underground constructions. A combination method of fibers and bacteria or mineral admixtures can be applied for better sealing crack and durability enhancement of underground concrete structures.

Sustainable Use of Waste Oyster Shell Powders in a Ternary Supplementary Cementitious Material System for Green Concrete.

The increasing concern for decarbonization and sustainability in construction materials is calling for green binders to partially replace cement since its production is responsible for approximately 8% of global anthropogenic greenhouse gas emissions. Supplementary cementitious materials (SCMs), including fly ash, slag, silica fume, etc., can be used as a partial replacement for ordinary Portland cement (OPC) owing to reduced carbon dioxide emissions associated with OPC production. This study aims to investigate the sustainable use of waste oyster shell powder (OSP)-lithium slag (LS)-ground granulated blast furnace slag (GGBFS) ternary SCM system in green concrete. The effect of ternary SCMs to OPC ratio (0%, 10%, 20%, and 30%) on compressive strength and permeability of the green concrete were studied. The reaction products of the concrete containing OSP-LS-GGBFS SCM system were characterized by SEM and thermogravimetric analyses. The results obtained from this study revealed that the compressive strength of concrete mixed with ternary SCMs are improved compared with the reference specimens. The OSP-LS-GGBFS ternary SCMs-based mortars exhibited a lower porosity and permeability compared to the control specimens. However, when the substitution rate was 30%, the two parameters showed a decline. In addition, the samples incorporating ternary SCMs had a more refined pore structure and lower permeability than that of specimens adding OSP alone. This work expands the possibility of valorization of OSP for sustainable construction materials.

A Bibliometric Analysis of Research Progress and Trends on Fly Ash-Based Geopolymer.

The objective of this work is to present the research progress and applications of fly ash-based geopolymer, and summarize the future research hotpots. Since 1998, scholars have made important contributions to the study of fly ash-based geopolymer, and a large number of research studies have been published. Therefore, a bibliometric analysis for the determination of the research status, trend, and history of fly ash-based geopolymer was conducted in the present study. A total of 4352 publications on fly ash-based geopolymer were collected between 1998 and 2022, with an increasing trend year by year. China and Australia are the largest contributors to the field, and the research institutions in each country cooperate closely. In addition, the most contributing research areas are MATERIALS SCIENCE, ENGINEERING, and CONSTRUCTION & BUILDING TECHNOLOGY. The keywords including fly ash, compressive strength, and mechanical property are the most frequently appearing words. On the whole, the development of fly ash-based geopolymer could be divided into three stages including the replacement of ordinary Portland cement, the development of multifunctional materials, and the reduction of environmental impact by the conversion of solid waste. This overview could provide an important guidance for the development of fly ash-based geopolymer.

Effects of Fly Ash Inclusion and Alkali Activation on Physical, Mechanical, and Chemical Properties of Clay.

This study investigated the improvement in the behaviour of a clay soil due to the addition of alkali-activated fly ash as a stabilising agent, and the effects of different activation factors such as alkali dosages and silica moduli. The alkali activator solution used was a mixture of sodium silicate and sodium hydroxide. Class F fly ash was used as the precursor material for the geopolymerisation process. Soil samples stabilised with non-activated class F fly ash were prepared and tested to compare the results with samples stabilised with alkali-activated fly ash. Compaction tests, unconfined compressive strength tests, X-ray diffraction analysis, and scanning electron microscopy analysis were carried out on samples cured 1, 7, and 28 days at room conditions. The results showed that the compressive strength of stabilised soil significantly increased when the fly ash was activated. The optimal activation parameters to stabilise the soil were found to be alkali dosages in the range of 12% to 16% and a silica modulus of 1.25. The highest compressive strength recorded was at 1293 kPa with an alkali dosage of 16% and a silica modulus of 1.25, while for the non-stabilised soil, it was at 204 kPa at 28 days of curing. Mineralogical analysis showed a decrease in the peak intensities of kaolinite and illite, while microstructural analysis indicated an alteration in soil texture with the addition of the alkali-activated fly ash.

Study on the Mechanical Properties, Wear Resistance and Microstructure of Hybrid Fiber-Reinforced Mortar Containing High Volume of Industrial Solid Waste Mineral Admixture.

The use of a high volume of industrial solid waste mineral admixture and hybrid fiber can greatly reduce the amount of cement in mortar or concrete, improve its performance, ensure the service properties of mortar or concrete, and reuse industrial solid waste to reduce the environmental burden, which has significant research significance. In this paper, the mechanical properties, wear resistance and microstructure of hybrid fiber-reinforced mortar (HFRM) with a high content of industrial solid waste mineral admixture were systematically studied under different water/binder ratios. Mineral admixtures include fly ash, silica fume and granulated blast furnace slag (slag). The total content of hybrid glass fiber (GF) and polypropylene fiber (PPF) was 2% by volume fractions, and six different water/binder ratios ranging from 0.27 to 0.62 were used. The following conclusions were drawn: fibers have a significant negative effect on the properties of mortars with a low water/binder ratio (w/b = 0.27) and high content of mineral admixtures. In general, the effect of adding hybrid fiber on improving the wear resistance of mortar is more obvious. The average residual weight of hybrid fiber-reinforced mortar is the highest after the wear resistance test. Comprehensively considering the compressive strength, flexural strength, wear resistance and microstructure of the mortar samples, G8PP2-0.40 is the optimal mix ratio. At this time, the replacement rates of fly ash, silica fume and slag are: 20%, 5% and 30%, the water/binder ratio is 0.40, and the content of GF and PPF is 1.6% and 0.4%, respectively.

Sustainable Utilization of Waste Oyster Shell Powders with Different Fineness Levels in a Ternary Supplementary Cementitious Material System

As cement manufacturing accounts for 8% of global CO2 emissions, there is an urgent need to tackle the environmental impacts of cement production and address the decarbonization of construction materials. Adopting supplementary cementitious materials (SCMs), including fly ash, slag, silica fume, etc., can be used as a partial replacement for ordinary Portland cement (OPC) to reduce CO2 emissions related to the OPC industry, while providing benefits for waste valorization. This study aims to explore the sustainable utilization of a waste oyster shell powder (OSP)–lithium slag (LS)–ground granulated blast furnace slag (GGBFS) ternary SCM system in green concrete. The effect of OSP fineness on compressive strength, hydration products, pore structure, and transport properties in ternary SCM-based mortars was studied using a wide array of experimental techniques, including thermogravimetric analysis (TGA), scanning electron microscopy (SEM) analysis, Mercury intrusion porosimetry (MIP), the water absorption test and the rapid chloride penetration test (RCPT). The results revealed that the concrete with the ternary SCMs showed equivalent compressive strength compared to reference specimens. The water absorption and chloride ion charge of the RCPT in the concrete containing the ternary SCMs decreased by up to 30% and 81.4%, respectively. It was observed that the specimens incorporating the OSP with a mesh size of 3000 exhibited the highest compressive strength and the most refined microstructure.

Low carbon and high efficiency limestone-calcined clay as supplementary cementitious materials (SCMs): Multi-indicator comparison with conventional SCMs

The increasing shortage of conventional supplementary cementitious materials, including fly ash (FA) and ground granulated blast furnace slag (GGBS), further obliterates the sustainability potential of Portland cement. Fortunately, recent studies have proved that limestone-calcined clay (LC2) is a feasible substitute. In this study, LC2 was used as SCM to study the properties of blended cement, and compared with FA and GGBS, the relevant mechanisms leading to the unique properties of LC2 were also explained. The evaluation indexes related to energy consumption and carbon emission were proposed. Results show that, contrary to the positive effects of FA and GGBS, LC2 has a negative effect on normal consistency and workability. LC2 slightly shorten the setting time at normal consistency, but at large content, the setting time was significantly prolonged due to the increase of consistency. LC2 diminished drying shrinkage and is superior to FA and GGBS. LC2 has higher cementing efficiency than FA and GGBS, and it is more obvious at early age. The environmental impact analysis also showed that LC2 reduced the relative energy consumption and carbon emission of cement, and reduces by about half at the substitution rate of 45 ∼ 60%.

Effects of crumb rubber inclusion on strength, permeability, and acid attack resistance of alkali‐activated concrete incorporating different industrial wastes

AbstractThis study examines the suitability of alternate binders and crumb rubber (CR) to produce light weight alkali‐activated concrete (AAC). For this, strength, and durability performance of AAC incorporating CR by partially replacing fine aggregate was studied. To produce AAC, four different binders, including fly ash, rice husk ash (RHA), metakaolin, and bottom ash were used. Fine aggregates were substituted with CR at 0%, 10%, 20%, and 30% for each AAC mix (with different binders). Furthermore, the mixes were prepared using 12 M sodium hydroxide (NaOH) solution, and the ratio of sodium silicate (Na2SiO3) to NaOH was taken as 2.5. The samples were cured at ambient temperature. Strength and durability properties, including permeability through water absorption and acid attack (hydrochloric acid [HCl] and sulfuric acid [H2SO4]), were also checked. Results of this study revealed that the strength decreased with the increase in CR content. Further, this decrease was high at 30% replacement but strength was satisfactory. AAC showed good relationships among compressive, flexural, and split tensile strengths. Similar footprints were observed for permeability results. However, highest water absorption was observed for bottom ash binder (with 30% substitution of CR). Mixes with fly ash and metakaolin binders outperformed the other mixes while comparing the compressive strength of acid exposed samples. Overall, a sustainable and durable light weight AAC can be prepared using 20% CR.

An industrial demonstration study on CO2 mineralization curing for concrete

SummaryA 10,000 ton-CO2/y mineralization curing (CMC) process was demonstrated in Jiaozuo city, China by retrofitting a traditional autoclaved curing plant. An industrial concrete formula with synergistic effects of aggregate gradation, early hydration, and alkali excitation was developed using local solid wastes resources. Approximately 90% of the raw materials, including fly ash, furnace blaster slag, steel slag, and carbide slag, came from coal-based industries. An extraordinary phenomenon of high-temperature accumulation from room temperature to 140°C was first observed in an industrial scale because of the rapid and strong exothermic carbonation reaction. A step pressure-equalizing procedure was developed to achieve a rapid carbonation rate, a high CO2 conversion ratio of >98%, and efficient carbonation exotherm recycling. The global warming potential life cycle analysis revealed that compared with autoclaved curing, CMC showed significantly decreased the emission of 182 kg CO2-Eq/m3-product, with direct CO2 sequestration accounting for ∼65% of the reduction.

Characteristic Strength of Concrete Using Steel Slag as a Fine Aggregate

Abstract: This paper describes the experimental inspection performed to evaluate the properties of concrete using steel slag as a fine aggregate. Concrete is the most commonly used material in the world, so it’s abounded used in civil engineering construction field leads to increasing in aggregate scarcity. Because it reduces the use of natural resources, industrial waste is encouraged in the construction industry. Common industrial waste materials include fly ash, silica fume, and steel slag. These materials are successfully used in the construction industry for partial and complete concrete replacement. In present study, partial replacement of fine aggregate by 0%,5%, 10% and 15% in M30 concrete grades with w/c ratio of 0.44. Keywords: Concrete, steel slag, compressive strength, split tensile strength and flexural strength test.

Phenotypic Responses of Some Functional Traits in Four Native Perennial Grass Species Grown on Fly Ash Dump and Native Soil.

Functional response traits of four perennial grass species (Imperata cylindrica, Cenchrus ciliaris, Sporobolus diander, and Cynodon dactylon) growing on the fly ash dump and referral site having native soil were evaluated with the objective of selecting species suitable for rapid development of vegetation cover on the fly ash dumps. All the four species showed spectacular plastic responses in functional traits of plants grown on the fly ash dump and are induced by habitat and hence are adaptive. The traits associated with the root system such as root length, spread, the volume of the substratum occupied by the root system, and root biomass showed greater plasticity than the traits of the shoot system such as shoot biomass, the mean number of tillers per clump, and mean height of tillers. For instance, for all the grass species, the ratio of root/shoot biomass was higher for fly ash grown plants as compared to that of plants grown in native soil. The highest ratio was recorded for C. dactylon (5.61 ± 2.36) and I. cylindrica (5.37 ± 2.36) whereas the lowest ratio was recorded for C. ciliaris (1.87 ± 0.44). This suggests greater allocation of resources to root than to shoot by the species for space exploitative growth that enables them to acquire nutrients from nutritionally poor and unfavorable substratum like fly ash dump. Such a strategy enables species to establish and regenerate on barren areas that include fly ash dumps. The higher root length, spread, biomass, and root/shoot ratio in plants of all the species grown on fly ash as compared to plants grown on the native soil substantiate that plasticity in functional traits enabled the species to adapt to stressed habitats. The plastic responses observed are specific to the trait, specific to the species, and specific to the environment. This is evident by the quantitative differences in the responses between traits within a species, between species, and between habitats. The phenotypic plasticity induced by the fly ash altered the relationships between functional traits of the plants. This is evident by the marked differences in the r-values for different character associations between plants grown on fly ash dump and native soil. The results suggest that all the four grass species evaluated can be used for the rapid development of vegetation cover on the fly ash dumps to mitigate environmental contamination.