Search results for "Geopolymer"
showing 10 items of 32 documents
6th Workshop on The New Boundaries of Structural Concrete 2022 University of Salento – ACI Italy Chapter
2022
Geopolymer cement is a viable alternative to ordinary cement in order to significantly reduce the emission of carbon dioxide related to the construction of concrete structures. Being made up of waste materials, geopolymer cement also helps to limit the use of new raw materials, leading to a considerable reduction of the environmental impact of the construction industry. During the last years, the use of Geopolymer Recycled Aggregate Concrete (GRAC) in structural members has been studied in several recent experimental research in which the behavior of either the material or structural member was investigated. A review paper will be done critically to compile the present research on the use o…
Pyrolysed cork-geopolymer composites: A novel and sustainable EMI shielding building material
2019
Abstract In this investigation, and for the first time, pyrolysed sustainable cork was used to produce waste-based geopolymer-cork composites with enhanced electromagnetic interference (EMI) shielding properties. The influence of the pyrolysed cork amount and the geopolymer porosity on the EMI shielding ability of the composites was studied. The maximum total shielding effectiveness (SET) values achieved by these novel building materials (−13.8 to −15.9 dB) are equal to any other reported geopolymer microwave (MW) absorbers over the X-band, despite containing much lower carbon content. In addition, our composites were produced using an industrial waste (biomass fly ash) as raw material and …
Synthesis of zeolite/geopolymer composite for enhanced sequestration of phosphate (PO43−) and ammonium (NH4+) ions; equilibrium properties and realis…
2021
Abstract Zeolite impeded geopolymer (Z/G) was synthesized from natural kaolinite and diatomite. The structure (Z/G) was characterized as an enhanced adsorbent for PO43− and NH4+ ions from aqueous solutions, groundwater, and sewage water. The synthetic Z/G structure exhibits sequestration capacities of 206 mg/g and 140 mg/g for PO43− and NH4+, respectively which are higher values than the recognized results for the geopolymer and other adsorbents in literature. The sequestration reactions of PO43− and NH4+ by Z/G are of Pseudo-Second order kinetic behavior considering both the Chi-squared (χ2) and correlation coefficient (R2) values. The sequestration reactions occur in homogenous and monola…
Mix design and mechanical performance of geopolymer binder for sustainable construction and building materials
2017
Sustainability in construction is a major concern worldwide, due to the huge volume of materials and energy consumed by this sector. Associated supplementing industries (e.g. Portland cement production) constitute a significant source of CO2 emissions and global warming. Valorisation and reuse of industrial wastes and by-products make geopolymers a solid and sustainable via to be followed as a valid alternative to Portland cement. In this work the mix design of a green fly ash-based geopolymer is evaluated as an environmentally friendly construction material. In the pursuit of sustainability, wastes from a regional kraft pulp industry are exploited for the material processing. Furthermore, …
Alkali activated materials using pumice from the Aeolian Islands (Sicily, Italy) and their potentiality for cultural heritage applications: Prelimina…
2020
Abstract In this paper, the potentialities of pumice-based geopolymers have been explored with the aim to evaluate their use as restoration materials. In particular, the behaviour of Aeolian pumice during alkali activation process, either alone or in binary mixtures with metakaolin, has been assessed using sodium hydroxide and sodium silicate activators. Hardened products were characterized by: X-ray diffraction; infrared spectroscopy; thermo gravimetry and electron microscopy. Furthermore, Hg-intrusion porosimetry, water absorption, compressive strength and colorimetric measurements were carried out in order to define the technical features of the produced geopolymers. The results reveal t…
Mix design and mechanical performance of geopolymeric binders and mortars using biomass fly ash and alkaline effluent from paper-pulp industry
2019
Abstract This work investigates the use of biomass fly ash (BFA) and an alkaline effluent (AEF), both generated from the Kraft pulp industry, in the preparation of geopolymeric binders and mortars for construction applications. BFA replaced the metakaolin (MK) while the AEF substituted the distilled water used to dissolve NaOH pellets. The mix design aims to maximize the amount of both the wastes and to optimize the materials properties, such as workability and mechanical performance. At the same time, also the environmental impact decreases enhancing the materials' sustainability and facilitating the circular economy. For the previously optimized BFA/MK ratio (70/30 wt.%) several NaOH/Na2S…
Comparative study of illite clay and illite-based geopolymer products
2011
Quaternary (Q-clay) clayey deposits are one of the dominating parts of mineral raw materials of the sedimentary cover at present area of Latvia. These clays can be characterised by illite content up to 75-80 %. Two ways for use of illite clays were studied: conventional and geopolymers method. Purpose of the second mentioned method was showing the influence of alkali (KOH) on the transformation of Q-clay/illite structure. Obtained products were investigated by IR–spectroscopy, DTA and XRD, pore size distribution was determined as well. Some ceramic properties and compressive strength were determined and compared. IR-spectrum showed the effect of alkali on the transformation of Q-clay/illite…
Organic-inorganic materials through first simultaneous frontal polymerization and frontal geopolymerization
2021
Abstract The first frontal geopolymerization (FGP) took place in the same reaction medium in which the frontal polymerization (FP) of 1,6-hexanediol diacrylate (HDDA) was occurring, thus giving rise to an organic-inorganic hybrid in one step in just a few minutes. Because of their exothermicity, the two reactions support each other and sustain propagating fronts. By contrast, using the classical techniques (prolonged heating) instead of FP, due to large gas formation, the reaction is explosive or, if carried out at room temperature, phase separation occurred.
Lessons Learned on the Tensile and Bond Behavior of Fabric Reinforced Cementitious Matrix (FRCM) Composites
2020
Fabric Reinforced Cementitious Matrix (FRCM) composites represent an effective, compatible and cost-efficient solution for strengthening and retrofitting existing structures. A strong research effort was done to investigate the tensile and bond properties of these materials, as well as the overall behaviour of strengthened members. A Round Robin Test was organized by Rilem TC 250-CSM on 28 FRCM composites comprising basalt, carbon, glass, PBO, aramid and steel textiles, embedded in either cement, lime or geopolymer mortars, to collect an experimental dataset and define test protocols. This paper collects the outcomes of this study to highlight fundamental properties of FRCM and to investiga…
The Suitability of Chemically and Thermally Activated Quaternary Clays of Latvia as Raw Material for Geopolymer Binders
2013
It is now accepted that new binders are needed to replace Portland cement (PC) for enhanced environmental and durability performance. The urge to reduce emissions of carbon and the fact that PC structures having built a few decades ago are already facing disintegration problems points out the handicaps of PC binders. Research works carried out in developing of alkali-activated binders show that this new type of binder could have a huge potential to become as alternative building material. Latvian Quaternary clays were studied from the point of view of the national economy, analysing the physical properties and chemical composition of those sediments in connection with the possibilities of …