Properties Of Ash Research Articles

Assessment of thermal and mechanical properties of fly ash based geopolymer blocks with a sustainability perspective using multi-criteria decision-making approach

Owing to the raising consciousness about the environment, geopolymers are slowly gaining the trust of researchers globally as the potential alternatives for the conventional building materials. Though, geopolymer emit far less CO2 than conventional building materials, the distance between the source and production site for a particular raw material can have significant impact on the environment. Thus, apart from meeting the mechanical and physical requirement of a building material, it must satisfy the sustainability requirement as well. Therefore, a combination of experimental and analytical method is adopted to select the optimal design mix to produce sustainable geopolymer block which fulfills the performance requirements as well. While compressive and flexural strength test were performed on the geopolymer block made using fly ash (FA) as the primary precursor and glass powder (GP) and steel slag (SS) as the partial replacement to ascertain its mechanical performance, physical performance was assessed by conducting tests like water absorption, bulk density, and thermal conductivity. The sustainability of geopolymer block is assessed by computing sustainability index based on embodied energy, global warming potential and global temperature potential. Multi-criteria decision making (MCDM) approach is then used to select the most optimal mix for geopolymer block production based on the mechanical, physical and sustainability index of each mix for geopolymer. A combination of FA-SS prepared with 14 M NaOH was found to be most sustainable based on the MDCM approach.

Study on Dielectric Properties of Rice Husk Ash Stabilized Soil

This study explored the impact of organic soil stabilizing agent on the engineering behaviors of subsoil commonly used for engineering applications in Nigeria. The soil obtained from a borrow pit and air-dried under laboratory conditions (30±5oC and 81±7% relative humidity). The dried soil sample was stabilized with rice husk ash (RHA) at the rate of 2, 4, 6, 8 and 10% (by mass of the soil) and cured for 14 days under natural conditions. A J-band microwave at a frequency of 7.0 GHz was used to measure the dielectric properties, while the standard proctor compaction test was used to determine the maximum dry density “MDD” and optimal moisture content “OMC” of the soil samples. Results obtained from the study depicted that the RHA had a significant effect on both the electrical properties of the soil. It was noted from the findings that, as the quantity of RHA used in stabilizing the soil increased from 0 to 10%, MDD values declined non-linearly from 1.61-1.42 g/cm3, while the OMC values inclined in a non-linear pattern from 14.8 - 17.1%. Similarly, the study results indicated that the soil dielectric constant and loss increased from 3.41 to 5.13 and 0.91 to 1.44 respectively, as the RHA incorporated into the soil raised by 10%. Present findings offer valuable insights into the fields of civil and electrical engineering, especially in the context of soil treatment for engineering applications.

Optimization of Alkali Activator on the Strength Properties of Fly Ash Based Geopolymer Repair Materials

Flexible and rigid road pavement deteriorates over time and needs high-performance patching repair materials. Cold mix asphalt patching is an easy and inexpensive repair material to repair potholes and other damaged roads. However, the repaired road pavement fails because it doesn’t have adequate compressive and bonding strength to the substrate. Thus, this research uses high-performance geopolymer repair materials to patch against road pavement potholes substrate. Geopolymer repair materials could improve the bonding strength, making them suitable for road repair purposes. For making geopolymer repair materials, the main materials used were high calcium aluminosilicate source materials such as fly ash, sodium hydroxide, sodium silicate, and water. This study tested the compressive and bonding strength of geopolymer repair materials after 1, 7, 14, and 28 days. This study found that the compressive strength of 90 g of alkali activator was the highest, at 37.0 MPa. The bonding strength improved gradually from day 1 to day 14, and then considerably on day 28. The compressive strength and bonding strength both increase in direct proportion to the amount of alkali activator present. Alkali activator is optimal at 90 grams for compressive strength and bonding strength of geopolymer repair materials.

Production of cleaner binders by reusing agricultural by-products: An approach towards zero cement concrete for sustainable future infrastructure

Alkali-activated binders are considered a low carbon alternative for cement. However, it is important to address the carbon dioxide emission and high cost associated with the currently used commercial activators. Hence, recent studies focus on developing sustainable, low-cost alternative activators. Although rice husk ash derived activator is a potential alternative to commercial activators, studies on rice husk ash derived activator is highly limited. Hence, the present study focuses on the performance evaluation of alkali-activated binders using rice husk ash derived activators. The effect of activators is studied for bagasse based binary and ternary alkali-activated binders. Moreover, the influence of rice husk ash derived activators is meticulously compared with commercial sodium silicate derived activators. In addition, the influence of heat and ambient curing was also investigated. Mechanical, durability and microstructural properties of bagasse ash based alkali-activated binders were assessed. Bagasse ash-fly ash based binders activated using rice husk derived activators yielded the maximum compressive strength. However, bagasse ash-slag based binders with commercial sodium silicate activators exhibited higher performance than rice husk ash derived activators. In the case of bagasse ash-slag-fly ash based ternary binders, specimens activated using the rice husk ash derived activator had better performance than specimens activated using the other conventional activators. Even though the addition of 10% bagasse ash increased the performance of fly ash based binders, the incorporation of bagasse ash reduced the performance of slag and ternary alkali-activated binders. The results also showed that the rice husk ash based activator is a feasible alternative for the activation of bagasse based precursors to generate desirable mechanical strengths and durability.

Оценка золошлаковых отходов как источника загрязнения окружаюшей среды и источника вторичного сырья

Introduction. Currently, more than 500 million tons of fly ash have been accumulated on the territory of the Republic of Kazakhstan, the volume of which will increase to one billion tons by 2030. Such accumulation of fly ash in storages creates a powerful anthropogenic impact on the biogeocenosis. A significant proportion of these man-made materials are formed during the burning of Ekibastuz coals. There is practically no processing of ash and slag waste on an industrial scale. For various reasons, ash dumps are not used in Kazakhstan, because the physico-chemical properties have been very poorly studied, in addition, during their processing, other wastes or ash dumps unsuitable for use are obtained from these wastes, because they contain a lot of unburned coal. As of 01.01.2020, the share of recycled, reused, burnt ash and slag waste in Kazakhstan amounted to 0.7%. The relevance and significance of this problem is due to the fact that man-made waste from CHP plants is not sufficiently processed, and current ash waste accumulates and occupies huge areas, which removes them from land use. Knowledge of the chemical composition of the ash will allow it to be used to obtain building materials. The purpose of this work is to study the properties of ash and slag waste during the burning of coal from the Ekibastuz deposit in Kazakhstan, to assess them as a source of environmental pollution, to determine the possibility of obtaining demanded building materials from them. Research methods. To determine the phase composition of the studied material, an upgraded diffractometer DRON-3M on CuKa radiation with software was used. Radiographs of the sample were obtained in the range of 2° (angles) from 10 to 70°. The chemical composition was determined using an energy dispersion spectrometer “EDX-8000”. Micrography of fly ash was taken on a scanning electron microscope Superprob-733. Research materials. Ash and slag waste from the burning of coal from the Ekibastuz deposit in Kazakhstan. Research results and discussion. The physical characteristics of ash have been established: specific surface area – ~200 m2/kg, true density – 2.1 g/cm3, bulk density – ~780 kg/m3. Fractional composition: the highest content of particles with a size of 100 microns (25.8%), 80 microns (12.12%), 50 microns (21.46%) and 45 microns (21.38%); at the same time, unburned carbon is concentrated in large fractions, glass phase – in small ones. Analysis of the chemical composition of Ekibastuzky ash allowed to find out the composition of coal minerals. The main components are silicon and aluminum oxides, and there is also a large amount of iron oxide. Knowledge of the chemical composition of ash allows it to be used in the production of building materials. Conclusion. The results of the conducted studies have shown the possibility of using ash and slag waste as secondary raw materials in the construction of road materials in order to reduce the anthropogenic load on the environment.

Effect of hydraulic binders on engineering properties of coal ash for utilization in pavement layers

Effect of hydraulic binders on engineering properties of coal ash for utilization in pavement layers

Physico-mechanical and thermal properties of fly ash and benzoylated Himalayan Agave fiber reinforced polyester composite

Physico-mechanical and thermal properties of fly ash and benzoylated Himalayan Agave fiber reinforced polyester composite

ГЕОПОЛИМЕРЫ, ПОЛУЧЕННЫЕ МЕХАНОАКТИВАЦИЕЙ ИСХОДНЫХ КОМПОНЕНТОВ: ОБЗОР ТЕКУЩИХ ТЕНДЕНЦИЙ

The reaction potential of a substance can be significantly increased by thermal, mechanical, and chemical methods. A combined method is also possible, as in the case of developing geopolymers, the technology of which involves treating precursors with chemical reagents. On the other hand, with the increase in the number of publications devoted to the development of geopolymers, research to reduce the amount of CO2 emissions and the cost of geopolymers production becomes relevant. This review examines three generations of geopolymers: 1 – metakaolin based geopolymers, 2 – geopolymers based on rocks, and 3 – fly ash based geopolymers. A comparative analysis of ways to improve the physical and mechanical properties of fly ash based geopolymers by mechanical activation is presented. It has been established that mechanical activation of fly ash, in addition to improving the strength characteristics of geopolymers, makes it possible to synthesize a geopolymer without thermal curing. After this, the focus is on the method of mechanical activation of fly ash and clay minerals, especially kaolinite. The particular interest in metakaolin based geopolymers is due to the high potential for widespread application, since these geopolymer technologies have greater potential to reduce CO2 emissions and, therefore, production costs. Also, the development of protection against heavy metals or radioactive substances requires the implementation of technology exclusively using geopolymers based on metakaolin.

ANALYTICAL PROCEDURES USING SEM/EDX EQUIPMENT FOR DETERMINING HEAVY METALS CONTENTS IN FLY ASH GENEREATED FROM DOMESTIC SOLID WASTE INCINERATORS: A CASESTUDY OF SOCSON WASTE-TO-POWER PLANT IN HANOI

The researching and establishing of as process for analyzing fly ash generated from a domestic solid waste treatment plant by SEM/EDX method were investigated. Three sampling series with twelve (12) fly ash samples collected at SocSon waste-to-power plant were used for: (i) analytical procedure establishment; (ii) standardization; and (iii) test analysis. At each measurement, a cross-check with one random sample using XRF method was carried out to verify the accuracy of the SEM/EDX measurements. As a result, a 6-step measurement procedure has been proposed, including: experimental preparation, sample weighting, liquid/solid phase separation, sample drying, sample measurement and data processing. And for procedure adjustment, liquid/solid phase separation were repeated twice while drying time was doubly increased from 24h to 48h to collect ll heavy metal contaminated residues. The proposed procedure could provide results in about 3-5 seconds without any requirement of sample digestion while most of the heavy metalspresent in fly ash, including low-content ones such as Ag, Cd and Cr were simultaneously displayed. The standardized measurement procedure was applied to test the hazardous properties of fly ash by comparing with QCVN 07:2009/BTNMT – National Technical Regulations on Hazardous waste thresholds. The results identified that fly ash could be primarily considered as hazardous waste with 5/14 heavy metal parameters exceed the limit from 1,7 to 9,5 times and needs to be collected and treated properly. This result is also quite similar to the studies that have been done in China, the US or Vietnam. Thus, SEM/EDX method could be used for analyzing heavy metal components in fly ash samples of solid waste treatment plants.

Thermal Properties and Drying Shrinkage Performance of Palm Kernel Shell Ash and Rice Husk Ash-Based Geopolymer Concrete.

This study aims to develop suitable formulations of geopolymer concrete (GPC) by varying the percentages of the geopolymer with aggregates and evaluating the performances in thermal and mechanical properties of palm kernel shell ash (PKSA)-GPC compared to rice husk ash (RHA)-GPC and ordinary Portland cement concrete (OPCC). Preliminary tests were conducted to select the best mix design ratios before casting the specimens. Then, the performance of the PKSA-GPC, RHA-GPC and OPCC specimens was evaluated based on their thermal performance and drying shrinkage. The mix designs of PKSA-GPC 70:30, PKSA-GPC 60:40, PKSA-GPC 50:50 and PKSA-GPC 66.6:33.3 were found to produce an acceptable consistency, rheological and thixotropic behaviour for the development of the GPC. PKSA-GPC showed a better thermal performance than the RHA-GPC and OPCC due to their strong and dense intumescent layers and slow temperature increment upon exposure to a high flame temperature from ambient temperature to 169 °C. The low molar ratio of the Si/Al present in the PKSA-GPC created a thermally stable intumescent layer. In the drying shrinkage test, PKSA-GPC 60:40 and RHA-GPC 60:40 shared an equal drying shrinkage performance (5.040%) compared to the OPCC (8.996%). It was observed that microcrack formation could significantly contribute to the high shrinkage in the PKSA-GPC 50:50 and RHA-GPC 70:30 specimens. The findings of this study show that PKSA could be incorporated into GPC as a fire-retardant material due to its capability of prolonging the spread of fire upon ignition and acting as an alternative to the conventional OPCC.

Measurements of the Permeability Coefficient of Waste Coal Ash under Hydrostatic Pressure to Identify the Feasibility of Its Use in Construction

The aim of this research was to measure the filtration properties of waste coal ash under the influence of hydrostatic pressure generated in a three-axial compression apparatus. The scope of work included determining the compactibility parameters, maximum bulk density and optimal moisture content. Permeability tests were performed for a sample with an average grain composition at three compaction indices IS: 0.964, 0.98 and 1.00. The hydrostatic pressure ranging from 0.5 to 1.8 bar corresponded to the layer depths from 2.17 to 7.83 m. Gradually increasing the pressure during the first loading cycle caused irreversible changes in the structure of the sample by local material agglomeration or grain interlocking. The water permeability coefficient was higher in the second loading cycle than in the first cycle. It was shown that waste coal ash cannot be used as a construction material on its own. To obtain constant filtration properties, the waste coal ash material should be doped, or an optimal compactionshould be used (IS = 1.00). The results presented in this study are important for assessing the use of waste coal ash for construction engineering purposes.

Retraction Note: An experimental investigation on mechanical, durability and Microstructural Properties of high-volume fly ash based concrete

Retraction Note: An experimental investigation on mechanical, durability and Microstructural Properties of high-volume fly ash based concrete

Influence of Gypsum on the Residual Properties of Fly Ash-Slag-Based Alkali-Activated Concrete

High-temperature exposures of concrete lead to serious damage in concrete structures, resulting in the significant decay of mechanical properties and spalling of concrete. Alkali-activated concretes (AAC) of blended aluminosilicate precursors and activators have been proven to have higher thermal endurance than conventional portland cement concrete. Incorporation of gypsum (GY) in alkali-activated systems has proven to positively impact the mechanical properties when adopted in controlled amounts. GY releases SO42- to the binder system, which helps in the formation of ettringites, along with Ca2+, which leads to the formation of hydrates. This causes a reduction in porosity and improves strength gain. Incorporation of GY into the fly ash-slag-based alkali-activated system further improves thermal endurance by retaining considerable residual strengths even after 800°C exposure. In the present study, the influence of GY on the residual mechanical properties of fly ash-slag-based AAC is investigated to explore the thermal endurance of the ternary mix at elevated temperatures. The mechanical properties of fly ash (FA), Ground Granulated Blast Furnace Slag (GGBS), and gypsum (GY) ternary blended AAC subjected to elevated temperatures are studied in comparison with conventional portland cement concrete (control mix). AAC design mixes with varying proportions of GY as a replacement to FA-GGBS precursor are tested for mechanical properties to obtain the optimum mix. The residual mechanical properties of the FA-GGBS-GY optimum ternary AAC mix are obtained after exposure to elevated temperatures up to 800°C. The morphology and microstructural characteristics of AAC are studied by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analyses to investigate the influence of gypsum on the thermal endurance of concrete when exposed to elevated temperatures. Improved thermal endurance is observed for AAC when FA-GGBS precursors are replaced with 5% of GY as compared to the thermal endurance of conventional portland cement concrete (PCC) of the same compressive strength. Doi: 10.28991/CEJ-2024-010-03-017 Full Text: PDF

Identification and characterization of tephra for geopolymer precursor

Abstract Volcanic ash and pumice are products of volcanic eruptions characterized by a high amount of amorphous silica and alumina. They can potentially serve as a source of raw materials for the production of geopolymers. Geopolymers are more environmentally friendly compared to conventional cement. However, there is a requirement for aluminosilicate for creating geopolymers. This study aims to identify the mineralogical composition and chemical properties of the volcanic ashes and pumices that are potentially used as geopolymers precursor materials. Tephra and pumice samples were collected from several volcanoes in Indonesia. The samples include two tephras from recently erupted volcanoes in Java and one pumice material from West Sumatra. Tephras were collected one week after the eruptions of Mt. Tangkuban Perahu (26th July 2019). Another source of tephra was collected from Mt. Kelud, which erupted on 13th February 2014. Pumice samples of Mt. Maninjau were collected at Sungai Limau district, 30 km from the Maninjau caldera, a product of the Holocene (52K) volcanic eruption of Mt. Maninjau. Mineralogy of the tephra and pumice samples was identified with XRF and XRD. Chemical properties characterized include pH, exchangeable cations, cation exchange capacity (CEC), potential-P, and available-P. Results showed that crystalline feldspar minerals and amorphous volcanic glass dominated volcanic ash and pumice. The SiO2 content is higher in pumice, followed by tephras from Mt. Tangkuban Perahu and Mt. Kelud (74.97%-60.28%). But the Al2O3 content is higher in Mt. Kelud compared to pumice and Mt. Tangkuban Perahu (23.57%-4.03%). The pH is very acidic to slightly acidic (2.35–6.1). Mg is higher than Ca, Na, and K. The potential-P and available-P were considered very low. Among the samples, Mt. Kelud volcanic ash has the highest available P compared to Tangkuban Perahu volcanic ash and pumice. The SiO2/Al2O3 ratio are 4.35, 8.00, and 26.38 for samples of Mt. Kelud, Mt. Maninjau pumice, and Mt. Tangkuban Perahu, respectively. The optimum ratio of geopolymer is between 2.5–5; thus, volcanic ash Mt. Kelud is the most suitable option. Nevertheless, the exchangeable basic cations of volcanic ash and pumice indicated that they are more suitable for plant nutrition.

Effect of Non-Class Fly Ash on Strength Properties of Concrete

Developing of green construction and reducing CO2emissions in the environment is a priority for industry in the coming years. Recycling fly ash in the concrete industry is a well-known way to reduce environmental impact. Aside from this benefit, there are numerous other positive effects of incorporating fly ash into concrete; however, in this research, the objective is to replace cement with a different percentage of non-class fly ash with high CaO, more than 42%. The analyzed variables are non-class fly ash properties, the effect of fly ash presence on the main properties of concrete and examining the optimum of non-class fly ash in ordinary concrete C-25/30 and high-performance concrete C-50/60. All investigations took place in the laboratory by producing 24 different mix designs and more than 1000 specimens to examine: consistency, setting time, shrinkage, and compressive strength in the short and long terms of curing. Recycling industrial waste in new construction, especially fly ash because of its non-uniform properties, still has some obstacles and is not a practical issue, but the future must be environmentally friendly, and this research proves that the objective of producing sustainable ordinary and high-performance concrete was achieved by replacing 40% of cement with non-class high CaO content fly ash. Doi: 10.28991/CEJ-2024-010-03-02 Full Text: PDF

Effective use of Waste Materials: A Case Study of Utilization of Fly Ash in Flexible Pavement Structures

Generation of energy through thermal processes is still dominant in many parts of the world. One of the by-products of this process is fly ash, whose safe disposal incurs monetary and environmental costs. To mitigate this issue, utilization of fly ash, as a construction material, has been increasing remarkably; however, evaluation and summarization of its use in pavement construction are not very common. This study reviews its utilization in construction from different aspects and attempts to fill the gap within the literature with a critical review of fly ash usage in pavement construction engineering for the last few decades. Further recommendations have also been suggested in this context. Class ‘C’ fly ash is used for soil stabilization and class ‘F’ is used in concrete. Review of the literature found the following results. Application of fly ash, in both flexible (asphalt) and rigid (concrete) pavement, is common in the form of a filler material. However, this paper only focuses on its use in flexible pavement layers. In the case of flexible pavement, fly ash is used can be used in surface, base, and sub-grade layers. The surface layer is made up of concrete, wherein it can be used as mineral filler or partial replacement of asphalt. The most common types of test performed on asphalt concrete are Marshall stability and tensile strength. However, there is a lack of field testing studies on asphalt concrete modified with fly ash. As for the other layers of flexible pavement, fly ash has been used with activators for their stabilization as these layers are made up of natural compact materials. Fly ash has shown promising results when used with cement, with both used within a proportion of 10%. The future research areas, identified through this review, are modeling of pavement layers modified with fly ash, and standardization of fly ash properties for use in pavement layers.

Carbon dioxide removal via weathering of sugarcane mill ash under different soil conditions

Sugarcane mill ash has been suggested as having high potential for carbon dioxide removal (CDR) via enhanced weathering (EW), but this had not been quantitatively assessed. The aims of this study were to 1) assess the CDR potential of various sugarcane mill ashes via EW, and 2) investigate the impact of soil conditions and mill ash properties on the CDR. This was done by characterising physical and chemical properties of five mill ashes from Australia and simulating weathering using a one-dimensional reactive transport model. The model was parameterised to simulate weathering of 100 t/ha of wet ash (47–65% water) or crushed basalt for 15 years under various combinations of soil pH and carbon dioxide partial pressure (pCO2). A sensitivity analysis was undertaken in a two-level factorial design to test the effect of pH, pH buffering, material surface area, infiltration rate, plant uptake of nutrients, organic matter cation exchange surfaces, and pCO2 on modelled CDR. The simulated CDR of the mill ashes was significantly less than the basalt (p < 0.001) but mostly did not differ significantly between ashes (p > 0.05). Weathering of mill ash removed 0.0–4.0 t CO2/ha (0.00–0.040 t CO2/t wet ash) cumulatively, similar to some basalts and olivine modelled in the literature. The theoretical maximum CDR of the mill ashes (based on amount of weatherable material applied) was achieved in around 5 years. The estimate of CDR varied by orders of magnitude depending on conditions. It was least when initial soil solution pH was lowest (4.5, unbuffered), pH was at 6.5 or less with constant buffering, and pCO2 was low (600 ppm). CDR was also significantly lower when calculated directly from accumulation of carbon in dissolved and solid phases rather than stoichiometrically from cation release. The effects of pH and pH buffering quantified here may explain low measured CDR from EW in field trials on acidic soils and highlight the need for more realistic modelling of pH buffering capacity. Overall, mill ash shows high potential for CDR via EW, especially if lifecycle benefits are considered, although this must be validated in the field.

Use of municipal solid waste incineration (MSWI) bottom ash as a permeable subgrade material: An experimental and mechanism study

ABSTRACT As a traditional method of waste treatment, municipal solid waste incineration (MSWI) has become one of the main methods of urban waste treatment. However, as a byproduct of MSWI, a large amount of MSWI bottom ash is not reused in current practice. This study innovatively posits MSWI bottom ash as an eco-friendly adsorbent rather than a pollutant, exploring its potential application as a permeable subgrade material. The results reveal that MSWI bottom ash exhibits promising properties to serve as a permeable subgrade material to achieve the permeability and improve the sustainability for subgrade. Due to the arrangement of its particles, it shows excellent performance in shear strength and permeability, which are comparable to or surpass those of sandy soils. The average pore width of 14.200 nm allows heavy metal substances to be encapsulated within the matrix, significantly reducing their leachability, thereby aligning with environmental friendliness standards. Its adsorption capacity is about 6.60 mg/g, and the adsorption capacity per volume is 3.66 times and 2.04 times that of fly ash and clay, respectively. The mechanism analysis shows that the adsorption process is monolayer heterogeneous adsorption. This paper presents a novel perspective on reusing MSWI bottom ash and provides evidence supporting its effective utilization as a permeable subgrade material, offering substantial environmental benefits through enhanced adsorption ability. Implications: Municipal solid waste incineration (MSWI) is a common method for municipal solid waste treatment, while the MSWI bottom ash is often not reused. This paper explored the explores the feasibility of using MSWI bottom ash as a permeable road base material. The results show that the particle arrangement enables excellent shear strength and permeability, comparable to sandy soil. It meets safety requirements for the leaching of heavy metals and acts as an adsorbent for pollutants leaching from permeable pavements. Furthermore, the mechanisms underlying these behaviors of MSWI were confirmed by microstructural and mineralogical analyses. These indicate that MSWI bottom ash has great potential as a permeable road base material. This paper provides a clear understanding of the physical, mechanical and environmental properties of MSWI bottom ash, which can promote its reuse in practice.

To Study the Performance of Bagasse Ash on the Strength of Concrete

Utilization of Sugarcane Bagasse ash as a supplementary cementations material adds sustainability to concrete by reducing the CO2 emission of cement production. The positive effects of bagasse ash as a partial replacement of cement on the mechanical properties of concrete are recognized through numerous researches; however, the extent of improvement depends on the durability properties of bagasse ash. In this study, durability properties of conventional concrete utilizing bagasse ash sourced from Sugar factory have been investigated. Concrete mixtures with Bagasse ash as 0, 5, 10, 15, 20, 25 and 30% total binder were used to cast the test specimens. The compressive strength, loss in mass of the bagasse ash and control concrete specimens were determined before and after exposure to elevated temperature and chemical attack. The 56-day compressive strength of the concrete mixtures varied from 3 to 26 MPa at elevated temperature conditions. The bagasse ash concrete samples showed less strength than the control concrete samples when designed for the same 56-day compressive strength of the control concrete. Inclusion of bagasse ash reduced the chemical attack significantly at 28 days and reduced further at 56days. In general, incorporation of bagasse ash as partial replacement of cement improved the durability properties of concrete. Key Words: Sugar Cane Bagasse Ash, Compressive Strength of Concrete, % content of SCBA

Influence of Nano-Fly Ash on mechanical properties, microstructure characteristics and sustainability analysis of Alkali Activated Concrete

Ordinary Portland Cement (OPC) composites significantly affect the atmosphere by emitting Carbon dioxide (CO2) during its production process. The addition of Nano Materials (NM) for the construction could change the matrix configuration at the nano level. Compared to other NMs, converting industrial by-products and locally available materials into nano size can enhance the characteristics of the binder composites. This research work focuses on the effects of Nano Fly ash (nFA), on the fresh, mechanical, microstructural, and thermal resistance properties of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) based Alkaline Activator Nano Concrete (AANC). The impact of adding nFA in various concentrations of 3 %, 6 %, 9 %, 12 %, and 15 % on the properties of AANC was studied. By adding nFA in an optimal proportion, the degree of geo-polymerization is improved which is found by Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Energy Dispersive X-Ray Analysis (EDAX) and Fourier Transform Infrared (FTIR). Results indicate that the addition of nFA significantly increased polymerization, reducing initial and final setting times by 13.3 %–52.5 % and 5.3 %–28.8 %, respectively. Moreover, nFA promoted the formation of polymer gel, leading to a denser microstructure with fewer cracks and refined pores, resulting in a substantial increase in mechanical strength, particularly with 9% nFA, achieving an optimal CS of 56.14 MPa after 28 days which is 37.97 % improvement compared to the mix without nFA. However, when nFA was added, beyond 9 %, the performances declined due to its high surface area resulting in a non-uniform dispersion that promoted agglomeration. This dispersion enhances the formation of C-A-S-H and C–S–H gels. The addition of nFA in AANC can be an environmentally friendly solution by reducing CO2 emissions, energy consumption, cost reduction and increased sustainability.