Assessing the suitability of fly ash geopolymers for high temperature applications

Geopolymers are an inorganic polymer synthesised from the dissolution and polycondensation of aluminosilicates in alkaline solutions under hydrothermal condition, yielding an amorphous, three-dimensional polymeric framework (Davidovits, 1991). They are a broad class of binding material with applications that range from conventional concrete to high tech, light weight composites for use in aviation. Geopolymers have also shown promise for use in high temperature applications, such as fire proof coatings, structural concrete in fire prone areas and thermal insulation for refractory type applications, due to their intrinsic thermal stability (Barbosa and MacKenzie, 2003a).This thesis reports on an investigation into the thermal performance of geopolymers synthesised from a range of fly ashes in order to assess their suitability for use in high temperature applications. Five fly ashes from Australian power stations with contrasting chemical properties were used in the study. Geopolymers were synthesised from each of the fly ashes using sodium silicate or sodium aluminate solutions in order to achieve a set range of Si:Al compositional ratios. Thermal analysis was conducted up to 1000 °C using a constant heat rate as well as a heating regime that simulated the conditions during a fire.The fly ashes were characterised in terms of elemental composition, phase composition, particle size, density and morphology prior to being used to synthesise geopolymers. It was determined that only a portion of each of the fly ashes was available for geopolymerisation and that the reactive Si:Al ratio (amorphous Si:Al ratio) varied greatly between the fly ashes. Collie and Port Augusta fly ashes had relatively low reactive Si:Al ratios (1.15 and 1.84, respectively) whereas Eraring, Tarong and Bayswater fly ashes had high Si:Al ratios (4.98, 8.84 and 7.49, respectively). All of the fly ashes had a predominantly spherical morphology, characteristic of fly ashes, though only the Collie and Port Augusta fly ashes had a significant portion of sub 5 μm particles.The thermo-physical, mechanical and micro-structural properties of the geopolymers made from each of the fly ashes are presented and the effect of the source fly ash characteristics on the hardened product is discussed. The results varied greatly with fly ash source and the most influential fly ash characteristic was the reactive Si:Al ratio. Fly ashes with a high reactive Si:Al ratio (≥5) were sodium aluminate activated and produced geopolymers with low to moderate as-cured compressive strengths but exhibited excellent dimensional stability during heating and greater compressive strengths after heating. Fly ashes with a low reactive Si:Al ratio (<2) were sodium silicate activated and produced geopolymers with high as-cured compressive strengths but exhibited poor dimensional stability during heating and greatly reduced compressive strengths after heating. All samples exhibited strength improving microstructural changes such as improved inter-particle bonding due to sintering after firing. However, the instability of non geopolymer phases during high temperature exposure led to strength losses in some samples depending on the type and composition of the activating solution.Geopolymers from three of the fly ashes were assessed for their performance upon exposure to a simulated fire. Solid and low density foamed variants (ρ ≈ 0.9 g cm-3, k ≈ 0.3 W m-1K-1) of the mixes were used for fire testing. Fire ratings of between 60 and 90 minutes for a sample thickness of 50 mm were achieved. The solid geopolymers exhibited better fire ratings than the low density geopolymers due to their higher water content (as they contained more of the hydrated geopolymer phase). Microstructural analysis of the fire tested samples indicated that the geopolymers were not significantly damaged by dehydration and the fire exposed side exhibited analogous changes to the samples that were gradually heated to 1000 °C.The results in this thesis indicate that fly ash geopolymers have great potential for utilisation in high temperature applications provided they are synthesised from a source material with suitable physical and compositional characteristics

Fighting to Save a Nation: Volunteerism and London’s Auxiliary Fire Service in the Blitz

The London Blitz of 1940 is one of the most horrifying events of World War 2. For the first time, citizens were the primary target in an attempt to shock Britain into surrender. The Blitz opened a new chapter in the book of WWII. Hitler wanted to reduce London to a pile of ashes and rubble. To accomplish this feat, the Germans introduced an entirely new air-raid strategy. Guided by a new tracking system, that allowed them to locate London even during government imposed blackouts, the Germans dropped a barrage of incendiary bombs over London. These small, tubular objects would lodge themselves in buildings and start small fires throughout the city. While harmless in small numbers, the Germans dropped tens of thousands of these incendiary bombs on London. As fires spread, the German bombers then began to drop massive explosives that leveled buildings throughout the city. On the front lines in the streets of London, fire brigades scrambled to contain the fires. Britain’s Auxiliary Fire Service (AFS) was established in 1937 to assist the regular fire brigades in the event of all-out war. When the Blitz took London by storm in 1940, the Auxiliary Fire Service was called into action. The AFS was made up of over 20,000 part-time and emergency full-time volunteers. Both men and women were played large roles in the AFS. Whether they were pump operators or communication staffers, there was still one glaring trait shared by many of these brave volunteers: they had no experience fighting fires (90% had never fought fires before the Blitz). While many lacked experience, the AFS played a major role in holding off the fires that threatened to reduce Britain to a pile of ashes. Churchill called AFS members “heroes with grimy faces.

Consortium fires up information exchange between land mangers and scientists for healthier, safer ecosystems

As the ashes continue to smolder from one of the biggest and most visible fires to strike northern Arizona in the last decade, scientists, land managers and fire fighters are working to spread knowledge about fire more effectively with each other and create on-the-ground results for a healthier ecosystem..

Rejecting Deconstruction and Welcoming Christian Mysticism: A Review of When Everything\u27s on Fire

This book is an invitation for us to recall and experience the history and tradition of the church that extends far back beyond the modern age. Posting about ­­­­­­­­the book When Everything\u27s on Fire from In All Things - an online journal for critical reflection on faith, culture, art, and every ordinary-yet-graced square inch of God’s creation. https://inallthings.org/rejecting-deconstruction-and-welcoming-christian-mysticism-a-review-of-when-everythings-on-fire-faith-forged-from-the-ashes

Frances Patton Statham Papers - Accession 574

The Frances Patton Statham Papers consists mainly of papers related to her literary career. Ms. Statham, Winthrop Class of 1951, has written several historical romances set in the south. The collection consists of correspondence, book reviews of From Love’s Ashes and On Wings of Fire, manuscripts of From Love’s Ashes, copies of her short story, “ When the Gypsies came”, newsletters and other publications related her involvement in the Atlanta Women’s Auxiliary, the Atlanta Professional Women’s organization, and to several literary societies, workshop pamphlets she attended, advertising items (magazines, flyers, posters, promotional photographs) for her publications, newspaper clippings, and a 1983 15 minute documentary film of Ms. Statham.https://digitalcommons.winthrop.edu/manuscriptcollection_findingaids/1688/thumbnail.jp

Stones resting on the top soil cause heterogeneous patterns of fire-induced water repellency

Depending on soil and fire characteristics, soil water repellency (SWR) may be induced, enhanced or destroyed by burning. The spatial pattern of SWR may be extremely heterogeneous as a consequence of the temperature peaks, the variation of fire temperature, the distribution of fuel, or the amount and type of ashes. In this research, we have studied the effect of stone cover and position on the intensity and spatial distribution of fire-induced SWR after low-, moderate- and high-severity fire. Generally, SWR increased with fire severity, but stones did induce some differences and increased the heterogeneity of the spatial distribution of fire-induced SWR. In low-stone-cover areas, SWR from soil surfaces below stones increased respect to non-covered soil surfaces. In areas under high stone cover, SWR increased from non-covered soil surfaces to soil surfaces below stones after low-severity fire. In moderate- and high-severity burnt soils under high stone cover, SWR was more severe than in non-covered soil surface, but no significant differences were observed.Ministerio de Economía y Competitividad CGL2010-21670-C02-0

Fuels and Burners for Domestic Heating

Discusses fuels and burners for domestic heating, including hand-fired coal or coke, automatic coal stoker, gas-fired heaters, oil burners. INlcudes table of comparative fuel costs

Propiedades de paneles geopoliméricos basados en ceniza volante y metacaolín bajo ensayos de resistencia al fuego

This paper presents the results of a study about the effect of fire on geopolymer paste composed of fly ashes, metakaolin and sodium silicate. 2 cm thick, 28 cm high and 18 cm wide panels were filled with the paste obtained. After 28 days of curing at 20 °C and 45% of relative humidity, different tests were carried out in the geopolymers: physico-chemical (density, water absorption, porosity), mechanical (flexural and compressive strength), fire resistance and environmental (leaching and radioactivity). The panels manufactured have been compared with other commercial panels in order to determine the recycling possibilities of fly ashes in manufacturing new fire-insulating geopolymers. The panels obtained can be utilized for the production of interior wall materials, with a good physical, mechanical, fire resistant properties without any environmental problem.Este documento presenta los resultados de un estudio sobre el efecto del fuego sobre pastas de geopolímeros compuestas de cenizas volantes, metacaolín y silicato sódico. Con la pasta obtenida se han rellenado paneles de dimensiones 2 cm de espesor, 28 cm de altura y 18 cm de ancho. Tras 28 días de curado a 20 °C y un 45% de humedad relativa, diferentes ensayos fueron realizados en los geopolímeros obtenidos: fisicoquímicos (densidad, absorción de agua, porosidad), mecánicos (resistencia a compresión y a flexión), de resistencia al fuego y medioambientales (lixiviación y radioactividad). Los paneles fabricados han sido comparados con paneles comerciales para determinar las posibilidades de reciclaje de las cenizas volantes para la fabricación de nuevos productos geopoliméricos con propiedades aislantes al fuego. Los paneles obtenidos pueden ser utilizados para la producción de paredes interiores, con buenas propiedades físicas, mecánicas y de resistencia al fuego sin ningún problema medioambiental

Ok Google, Start a Fire. IoT devices as witnesses and actors in fire investigations.

Fire incidents are amongst the most destructive events an investigator might encounter, completely transforming a scene with most of the objects left in ashes or highly damaged. Until now, fire investigations relied heavily on burn patterns and electrical artifacts to find possible starting locations, as well as witness statements and more recently witness imagery. As Internet of Things (IoT) devices, often seen as connected smart devices, become more common, the various sensors embedded within them provide a novel source of traces about the environment and events within. They collect and store information in different locations, often not touched by the event, such as remote servers (cloud) or companion smartphones, widening the investigation field for fire incidents. This work presents two controlled fire incidents in apartments that we furnished, equipped with IoT devices, and subsequently burnt. We studied the traces retrievable from the objects themselves after the incident, the companion smartphone apps, and the cloud and assessed the value of the information they conveyed. This research highlighted the pertinence to consider traces from IoT devices in the forensic process of fire investigation