The paper reports the outcome of the research work on mechanical and microstructural changes to palm oil fuel ash engineered alkali-activated cementitious composite (POFA-EACC) mortar exposed to di...
#1Promoda Behera(Technical University of Liberec)H-Index: 4
#2Vijay Baheti(Technical University of Liberec)H-Index: 17
Last. Salman Naeem(Technical University of Liberec)H-Index: 6
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Abstract The present work deals with the effect of carbon microfiber addition on the development of microstructure and mechanical properties of geopolymers at elevated temperature. The carbon microfibers were prepared from recycled inexpensive carbon fibrous wastes by ball milling, and then subsequently incorporated under 5, 10 and 15 wt% loading into metakaoline based geopolymers. The addition of carbon microfibers was found to produce compact structure of geopolymers due to their pore filling ...
#1Messina(Parthenope University of Naples)H-Index: 1
#2Ferone(Parthenope University of Naples)H-Index: 1
Last. Cioffi(Parthenope University of Naples)H-Index: 1
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Abstract Waste fly ash, referred in literature also as “weathered”, represents a major management issue for coal-fired power plants. The low qualification of this relevant fraction of produced fly ash is not adequate for recycling in structural concrete. Non-structural applications may represent an economically feasible solution to maximize the recovery of coal fly ash from power plants. A potentially valuable recycling track may be represented by alkaline activation for the production of sustai...
Abstract Alkaline activated concretes based on a mixture of fly ash (FA) and blast furnace slag (GBFS), as well as FA and Portland cement (OPC), both at a ratio of 80:20, were exposed to temperatures between 25 °C and 1100 °C. Then, the physicochemical and mechanical changes were evaluated. The results indicate that the activated concretes have better performance than the reference ones (100% OPC). At temperatures of 1100 °C, the residual strengths of the FA/GBFS and FA/OPC concretes are 15 and ...
Last. Jian-Guo Dai(PolyU: Hong Kong Polytechnic University)H-Index: 34
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Abstract This study investigates the effects of high temperatures and exposure duration on the flexural behavior and microstructure of hybrid basalt textile and steel fiber reinforced alkali-activated slag panels. Three-point bending tests were conducted after heating specimens to 400 °C, 600 °C, and 800 °C for durations of 1 and 2 h. The effects of thermal exposure on the matrix and the basalt fibers from the panels were investigated with scanning electron microscopy. Element and phase analyses...
Last. Julie Bregulla(Building Research Establishment)H-Index: 7
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This chapter begins by describing the thermal decomposition of constituents (polymer and natural fibre reinforcement) of natural fibre composites (NFCs). It then investigates the fire performance of NFCs, including reaction to fire testing, heat transfer of NFC building materials, thermal decomposition and fire resistance of NFCs. The chapter also includes a review of the modelling fire performance of NFCs, its residual mechanical properties and its thermoroperties.
Abstract This paper presents the effects of sodium and potassium based activators on compressive strengths and physical changes of class F fly ash geopolymer exposed to elevated temperatures. Samples were heated at 200 °C, 400 °C, 600 °C and 800 °C to evaluate the residual compressive strength after 28 days of curing. The fly ash geopolymer were synthesized with combined sodium silicate and sodium hydroxide solutions and potassium silicate and potassium hydroxide solutions by varying mass ratios...
Abstract This research focused on developing thermally-stable materials based on alkali-activation of slag, fly ash, and metakaolin compared to portland cement mixtures by using a hierarchical approach to material design. At lower length scales, X-ray diffraction (XRD) characterized the mineralogy that coupled to higher length scale experiments using thermogravimetric analysis (TGA) for determining the materials thermal stability. Additionally, high-energy X-ray computed microtomography (μCT) de...
Abstract In this study, the opportunity of employing quartz powder (QP) to improve the workability as well as the compressive strength of alkali-activated fly ash (AAFA) pastes before and after exposure to thermal loads has been investigated. Fly ash (FA) was partially substituted with QP at percentages ranging from 0% to 30% with an interval of 5%, by weight. After curing, specimens were exposed to different thermal loads ranging from 400 °C to 1000 °C with a step of 200 °C with a heating rate ...
Abstract This paper presents the effects of two types of alkali activators (Na and K-based) on the residual mechanical properties of steel fibre reinforced geopolymer concretes (SFRGC) after exposed to various elevated temperatures and compared with those of steel fibre reinforced concrete (SFRC). Compressive strength, indirect tensile strength and elastic modulus of above three types of steel fibre reinforced concretes are measured after exposure to elevated temperatures of 200, 400, 600 and 80...
Abstract As a result of tightening of environmental legislation, there is a renewed interest in the technology of alkali activated concrete also known as geopolymer concrete (GPC). Yet, for GPC to assume its own niche in the construction market, it must display equal or better properties at elevated temperatures than Ordinary Portland Cement (OPC) concrete. Currently there is sufficient evidence that GPC has a better resistance to fire; however not all of its behavioural aspects at high temperat...