USE OF FLY ASH AS CEMENTITIOUS MATERIAL IN CONC

The rise in paper waste from the paper processing sector is becoming the most important issue of disposal by filling large space and polluting the atmosphere, as it rises day to day. To decrease the paper waste as well as environmental emissions, it is recommended to use the paper waste in concrete as Hypo sludge. That contains the properties of cement such as SiO2 & Mg. Cement is the predominant material in concrete. In this research cement is replaced with fly ash as well as hypo sludge. By adding 5percent of fly ash and 0%, 3 %, 6%,9%,12% and 15% of hypo sludge, split tensile strength & compressive strength of concrete as well as Hypo sludge concrete efficiency are being tested. Split tensile strength & compressive strength of hypo sludge concrete are improved by the experiment up to 9% behind this % strength will decrease. In this journal the extension of research work is added that is flexural strength of concrete adding fly ash & hypo sludge in concrete and durability of concrete are studied. Performance of hypo sludge concrete, result and optimum percentage are mentioned in this paper.

Fly ash has become an important component of concrete as supplementary cementitious material with the development of concrete technology. To make use of fly ash efficiently, four types of fly ash with particle size distributions that are in conformity with four functions, namely, S.Tsivilis, Andersen, Normal and F distribution, respectively, were prepared. The four particle size distributions as functions of the strength and pore structure of concrete were thereafter constructed and investigated. The results showed that the compressive and flexural strength of concrete with the fly ash that conforming to S.Tsivilis, Normal, F distribution increased by 5-10 MPa and 1-2 MPa, respectively, compared to the reference sample at 28 d. The pore structure of the concrete was improved, in which the total porosity of concrete decreased by 2-5% at 28 d. With regarding to the fly ash with Andersen distribution, it was however not conducive to the strength development of concrete. Regression model based on the grey multiple linear regression theory was proved to be efficient to predict the strength of concrete, according to the characteristic parameters of particle size and pore structure of the fly ash.

[ID] Concrete is a very popular building material used in the world of construction services, consisting of a mixture of Portland Cement (PC) or other hydraulic cement, fine aggregates, coarse aggregates and water, with or without using additional materials. The quality of materials such as cement also greatly affects the strength of the concrete after hardening, so the selection of cement quality must be in accordance with the concrete planning regulations in order to obtain optimal results. In Indonesia there are many new cement factories that produce to meet the needs of the community, one of which is the Conch brand cement. So in connection with the above, Conch cement can be examined to compare the value of compressive strength and flexural strength with old cement, namely cement Padang, Tiga Roda, Holcim and Bosowa which are generally always used in concrete planning at this time.The purpose of this study was to determine the comparison of compressive strength and flexural strength of the concrete and the multiplier between cement Padang, Three Wheels and Conch at 28 days of age. In this study using the method SNI 03-2834-2000. With cylindrical test specimens (150 mm x 300 mm) and size beams (150 mm x 150 mm x 600 mm) three specimens were made for each cement.The maximum concrete compressive strength is found in Padang cement with a compressive strength of 45.86 Mpa, for the minimum compressive strength found in Tiga Roda cement with compressive strength value of 40.19 Mpa and for the compressive strength of cement Conch there is a second with compressive strength value 42.84 Mpa. From the explanation above, the results of 28 days of concrete compressive strength with each cement brand still not reached the planned concrete compressive strength of 38 MPa. The maximum concrete flexural strength is found in Padang cement with a flexural strength value of 5.03 Mpa, for a minimum flexural strength value found in Tiga Roda cement with a flexural strength value of 3.96 Mpa and for the value of Conch cement compressive strength there is a second with flexural strength 4.43 Mpa. From the explanation above, the results of 28 days of concrete flexural strength with each cement brand that has not reached the 4.4 Mpa plan, namely the three-wheeled cement brand.
 [EN] Concrete is a very popular building material used in the world of construction services, consisting of a mixture of Portland Cement (PC) or other hydraulic cement, fine aggregates, coarse aggregates and water, with or without using additional materials. The quality of materials such as cement also greatly affects the strength of the concrete after hardening, so the selection of cement quality must be in accordance with the concrete planning regulations in order to obtain optimal results. In Indonesia there are many new cement factories that produce to meet the needs of the community, one of which is the Conch brand cement. So in connection with the above, Conch cement can be examined to compare the value of compressive strength and flexural strength with old cement, namely cement Padang, Tiga Roda, Holcim and Bosowa which are generally always used in concrete planning at this time.The purpose of this study was to determine the comparison of compressive strength and flexural strength of the concrete and the multiplier between cement Padang, Three Wheels and Conch at 28 days of age. In this study using the method SNI 03-2834-2000. With cylindrical test specimens (150 mm x 300 mm) and size beams (150 mm x 150 mm x 600 mm) three specimens were made for each cement.The maximum concrete compressive strength is found in Padang cement with a compressive strength of 45.86 Mpa, for the minimum compressive strength found in Tiga Roda cement with compressive strength value of 40.19 Mpa and for the compressive strength of cement Conch there is a second with compressive strength value 42.84 Mpa. From the explanation above, the results of 28 days of concrete compressive strength with each cement brand still not reached the planned concrete compressive strength of 38 MPa. The maximum concrete flexural strength is found in Padang cement with a flexural strength value of 5.03 Mpa, for a minimum flexural strength value found in Tiga Roda cement with a flexural strength value of 3.96 Mpa and for the value of Conch cement compressive strength there is a second with flexural strength 4.43 Mpa. From the explanation above, the results of 28 days of concrete flexural strength with each cement brand that has not reached the 4.4 Mpa plan, namely the three-wheeled cement brand.

Low-lime fly ashes produced from modern coal-fired power technologies (developed to enhance efficiency/lower emissions), including nitrogen oxide (NOx) reduction, co-combustion, supercritical steam and oxy-fuel combustion, and their effects on chloride ingress and carbonation of concrete are investigated in this paper. Earlier work indicates that some of these technologies influence fly ash properties, but they mainly follow typical behaviour found for the material (consistence and compressive strength) in concrete. Both accelerated and normal-type exposure tests were carried out on a range of practical water/cement ratio concretes (also enabling interpolation for comparisons at equal 28 d strength). The test fly ash concretes were evaluated against (i) those containing three reference fly ashes covering a range of fineness and (ii) corresponding studies on fly ash concretes from the 1990s. The results show that there was an influence of fly ash fineness, reflected in reactivity/porosity (measured on mortar), and aspects of chemistry on chloride ingress, but there appeared to be minor material effects on carbonation. Comparison with the 1990s data indicated similar behaviour for the materials between studies for both properties. A relationship was also identified for the product of reactive alumina and sub-10 μm contents of the modern fly ashes and chloride resistance of concrete.

Aimsnnnnnn n This thesis investigated the use of fly ash in concrete by establishing reliable andnaccurate test data on the properties of concrete incorporating different fly ashncontent. In addition, the study focussed on typical uses by local governmentnauthorities in pathways, such as footpaths and bicycle ways, and also looked atnenvironmental impacts, incorporating durability and construction constraints in thenlife cycle costing issues. The aims of the project were:nnn nnn b To obtain experimental data on mechanical properties and durabilityncharacteristics of fly ash concrete containing 23-50% fly ash with a 28-dayncompressive strength of 25MPa;n b To assess the effect of curing on the properties of concrete incorporatingndifferent percentages of fly ash; andn b To draw conclusions as to the cost effectiveness of concrete incorporatingnlarge amounts of fly ash by comparing life cycle assessments that includendurability, construction and environmental factors.nnnnn n Scopenn n This investigation of the high volume fly ash concrete was for the purpose ofnextending its application in footpaths and bicycle ways. Several concrete mixesnusing fly ash at levels ranging between 23-50% as a partial replacement ofnPortland cement were investigated. All concrete mixes had a 28-day compressivenstrength of 25MPa, and were applicable to the footpaths and bicycle waysnconstruction. The effect of fly ash on the mechanical properties of the concretenmixes was determined under standard moist curing and ambient conditions. Thentested properties included setting time, compressive strength, splitting tensilenstrength, flexural tensile strength, drying shrinkage and abrasion resistance.nnnnnn n The test apparatus, procedures and testing data are described in detail. Testnresults are reported and compared. In addition to the experimental work, a simplenlife cycle assessment (LCA) and life cycle cost analysis (LCCA) were undertaken to evaluatenthe environmental impact and cost effectiveness of using high volume flynash in concrete pavement construction. The energy consumption and CO2nemissions were compared between high volume fly ash concrete and the typicalncommercial concrete in the environmental life cycle assessment. The life cycle costnanalysis included the costs of initial material cost, construction, rehabilitation, andnresidual values in the whole life cycle period of pavement structures.nnnnnn n Conclusionsnn n According to the analysis of the experimental results, it is feasible to producenconcrete with fly ash replacement of up to 50%, without significantly altering thenconcrete properties in the hardened state. However, high volume fly ash concretenwith 50% fly ash replacement retarded the setting time by up to 6.5 hours, whichnshould be considered in LCCA. High-volume fly ash concrete gained highernultimate strength under standard moist curing conditions. In typical pavementnconstruction, it is often difficult for the design engineer to ensure that adequatencuring, as per the construction specification, occurs. Indeed, evidence suggestsnthat in many applications curing of concrete pavements does not occur at all.nHowever, without adequate curing, no strength development was observed after 28ndays for high volume fly ash concrete. The 28-day abrasion resistance is verynsimilar for all mixes with various fly ash percentages, but use of a curing compoundnincreased the wear and tear properties of fly ash concrete to some extent.nnnnnn n Based on the information provided by the local industry and the results of thenenvironmental life cycle assessment and life cycle cost analyses, the followingnconclusions are summarized:nnn nnn b From the environmental life cycle assessment, 50% fly ash concrete is the bestnalternate for pavement design with 20% energy and CO2 savings compared tontypical concrete;n b However, in terms of life cycle cost analysis, when variability is considered innthe inputs (cost, setting time, service life, etc.), the typical 23% fly ash concretenwould be the most cost effective material in footpath and bicycle waysnapplications; andn b The results of LCCA are highly dependent on the setting time of concrete.nWhen using setting accelerator admixture in high volume fly ash concrete, the costneffectiveness is dependent on the efficiency of the admixture to reducensetting time. Without an increase in construction cost, the high volume fly ashnconcrete would have a similar life cycle cost to typical concrete.n

Due to rapid infrastructure development the outlay of conventional material is greater than ever day by day. Quality control is the major concern in design mix concrete for structural strength consideration. Sometimes conventional materials like cement and sand may not be reached up to the mark of required strength of good quality also. This research paper is intended to lead the advancement of hybrid mode substitution of OPC and river sand by using Fly Ash and manufactured-sand including coconut fibers respectively. In the present research work concrete properties are thoroughly studied to find out the compressive strength, tensile strength and flexural strength of concrete by using fly ash and manufactured sand including coconut fibers in the generalized mix design of concrete. A design mixed generalized procedure has been invented here for 50% cement-50% fly ash sand and 50% natural sand-50 % M-sand to observe changes in the strength of concrete. A comparative study was done and it was concluded that manufactured sand as well as fly ash can be adopted effectively up to 60-65% in concrete mix for better strength including 5% of coconut fibrous to mitigate the environmental disasters.

When released into the environment as solid waste, the by-product of coal called fly ash (FA) produced by coal-based electric power plants is detrimental. A further 8% to 10% of the worldwide anthropogenic emissions are produced by cement manufacturers. These issues may be resolved with high-volume fly ash (HVFA) concrete. HVFA concrete technology refers to employing fly ash instead of cement in the concrete mix to reduce the manufacturing of cement. But when the amount of fly ash in the concrete mix increases, the concrete’s compressive strength gradually decreases. The objective of this research is to determine the mechanical properties such as the compressive strength of HVFA concrete and compare it to the strength of the control concrete by adding Calcium Oxide (CaO) as an activator. Besides this, this research has another objective to reduce the use of cement in construction by replacing it with fly ash and making an environmentally friendly form of emission of CO2 while producing cement for the cement industry. In this research, different percentages of FA such as 20, 40, 50, 60, 70, and 80 percent are adopted replacing cement in concrete mixes with and without CaO. For this, cylindrical molds with dimensions of 100 mm × 200 mm were used for preparing concrete specimens. For each percentage of HVFA concrete mixtures, 3 (three) molds were cast without the activator and the same with the activator (2% of the binding material). A total of 117 concrete specimens were cast for the compressive strength test. These molds were cured using the water-curing technique. For determining mechanical properties, the compressive strength tests after 7, 28 and 56 days were conducted. Comparisons were made between the compressive strengths of HVFA concrete with and without the activator. These outcomes were contrasted with the compressive strength of the molds of conventional concrete. The early results for the compressive strength of HVFA concrete are extremely poor. The HVFA concrete’s 28-day compressive strength test results demonstrate a much higher compressive strength than the 7-day strength. However, the HVFA concret’s 56-day compressive strength test results were more satisfactory. According to this research, long-term water curing effectively boosts the compressive strength of HVFA concrete. Additionally, the use of CaO as an activator in HVFA concrete results in a minimum of 2 MPa higher compressive strength compared to HVFA concrete without the use of an activator. This result was therefore satisfactory for concrete with the activator content for up to 60% HVFA.

This study aims to utilize fly ash and waste PET bottles for producing more sustainable self-compacting concrete (SCC) with better mechanical strength. Fly ash is utilized as a supplementary cement material and waste PET bottles as fiber reinforcement to improve its flexural strength and achieve the targeted compressive strength. The experimental works were conducted on eight variations using 80 specimens, divided into two main groups of partial cement replacement using 0% and 15% fly ash by weight. The two variants are added with PET fiber based on the volume fractions of 0%, 0.25%, 0.50%, and 0.75%. Fresh concrete was tested using the slump flow method (T50) and the Visual Stability Index (VSI) based on ASTM 1611. The hardened concrete tests are conducted after 56 days and include testing the concrete's compressive strength, flexural strength, and ultrasonic pulse velocity. Test results showed that the presence of PET fiber in the SCC mix decreased its flowability. However, when added up to 0.75%, the mixes still meet the flowability requirements of fresh-state SCC. PET fiber addition tends to reduce the compressive strength, whereas the reduction in compressive strength of SCC with PET fiber without fly ash is insignificant. However, in SCC that uses fly ash, the addition of PET fiber causes a significant decrease in its compressive strength. Adding PET fiber into SCC mixes can increase flexural strength, both for the two variants: SCC without fly ash and SCC with fly ash. It can be concluded that PET waste fiber with an aspect ratio of 40 can be added up to 0.5% for SCC without fly ash and up to 0.25% by volume fraction for SCC with fly ash addition. The ultrasonic pulse velocity test results have an excellent tendency to predict the concrete's compressive and flexural strengths. Therefore, the UPV test can be applied for the non-destructive test evaluation of PET fiber-reinforced SCC. Doi: 10.28991/CEJ-2023-09-02-014 Full Text: PDF

The present study focuses on the possibility of use of alkali activated binders for use in concrete pavements. Alkali Activated Slag Concrete (AASC) and Alkali Activated Slag Fly ash Concrete (AASFC) are prepared and the properties are compared with Ordinary Portland Cement Concrete (OPCC). The Ground Granulated Blast Furnace Slag (GGBFS) and Fly Ash (FA) are blended in the ratios 100:0, 75:25, 50:50 and 25:75 as binder and activated using strong alkaline solution. Trial mixes are carried out to identify the optimal Activator Modulus (Ms) for each combination of GGBFS and FA. The mix design for the optimal activator modulus is optimised to achieve sufficient strength for Pavement Quality Concrete (PQC) and the fresh and mechanical properties are studied in detail. The results indicate the properties of AASC and AASFC are similar or slightly better than conventional OPCC and satisfy the minimum strength requirements for concrete pavements. The application of alkali activated binders will minimise the environmental hazards occurring from augmented OPC production, along with effective utilisation of industrial waste materials and conservation of natural resources.

Utilization of ceramic waste as fine aggregate within Portland cement and fly ash concretes

This paper investigates the compressive strength properties of concrete with Ground Granulated Blast Furnace Slag (GGBS) and Fly Ash in concrete by partial replacement of cement. The incremental demand of cement in the construction field is a concern for environmental degradation, in this regard; replacement of cement is carried out with waste materials by using GGBS and Fly Ash. On optimum level of GGBS and Fly Ash was assessed with varied percentage from 0 to 30% for different curing days. Replaced concrete were tested with the slump, compaction factor, Vee-bee and compressive strength. Cement to water ratio was maintained at 0.47 for all mixes. The compressive strength tests were conducted for 3, 7, 14 and 28 days of curing on a M25 grade concrete. The results obtained from the slump, compaction factor, Vee-bee and compressive strength of concrete containing GGBS and Fly Ash was increased as the curing time increases. The workability of replaced concrete improved when slump value achieved 30% as compared to controlled one SF0 and the compressive strength obtained 26.30% improvement at SF9 as compared to SF0. The outcomes indicated that the addition of GGBS and Fly Ash enhances the workability and compressive strength which eventually improved the mechanical properties of concrete.

Portland cement production process which is the conventional concrete constituent materials always has an impact on producing carbon dioxide (CO2) which will damage the environment. To maintain the continuity of development, while maintaining the environment, Portland cement substitution can be made with more environmentally friendly materials, namely fly ash. The substitution of fly ash material in concrete is known as geopolymer concrete. Fly ash is one of the industrial waste materials that can be used as geopolymer material. Fly ash is mineral residue in fine grains produced from coal combustion which is mashed at power plant power plant [15]. Many cement factories have used fly ash as mixture in cement, namely Portland Pozzolan Cement. Because fly ash contains SiO2, Al2O3, P2O3, and Fe2O3 which are quite high, so fly ash is considered capable of replacing cement completely.This study aims to obtain geopolymer concrete which has the best workability so that it is easy to work on (Workable Geopolymer Concrete / Self Compacting Geopolymer Concrete) and obtain the basic characteristics of geopolymer concrete material in the form of good workability and compressive strength. In this study, geopolymer concrete is composed of coarse aggregate, fine aggregate, fly ash type F, and activators in the form of NaOH and Na2SiO3 Be52. In making geopolymer concrete, additional ingredients such as superplastizer are added to increase the workability of geopolymer concrete. From this research, the results of concrete compressive strength above fc' 25 MPa and horizontal slump values reached 60 to 80 centimeters.

This study was conducted to evaluate the sensitivity of compressive strength, water permeability and electrical resistance of near-surface layer concrete with different fly ash contents to curing conditions. It is shown that the sensitivity to curing condition and fly ash content descends in the following order: difference between internal and surface resistivity (ρ) at 28 days, water permeability and compressive strength; both of longer duration of moist curing and use of fly ash in concrete enhanced the water penetration resistance. It is indicated that the resistivity difference ρ at 28 days can reflect accurately the curing history of fly ash concrete regardless of mix proportions; and use of fly ash in concrete requires longer moist curing duration.

This study investigated the effects of steel fibers on the fresh and hardened properties, and heat of hydration of concrete containing FA (Fly Ash). A total of 192 samples were cast comprising cubes, cylinders, and prisms, for six concrete mixes with varying contents of steel fibers by volume and a fixed content of FA i.e. 15% by weight of cement. The semi adiabatic setup was used to monitor temperature rise due to the heat of hydration in the concrete mixes for fourteen days. The use of FA increased workability, and decreased early compressive strength, tensile strength and heat of hydration of concrete. However, an increase in the compressive strength of FA concrete was observed by the addition of steel fibers up to 0.9% whereas a consistent increase in the splitting tensile strength and modulus of rupture was observed with the addition of the steel fibers from 0.4-1.8%. Further the test results showed that increasing steel fibers content decrease the evolution of heat due to hydration. It was concluded that the FA concrete with steel fibers can be used in precast industry and mass construction projects due to the improved mechanical properties and lower heat of hydration.

Strength-based life cycle CO2 of fly ash concrete: Variation with common mix parameters