scholarly journals GEOPOLYMERS SYNTHESIZED FROM PHILIPPINE COAL ASH AS SUSTAINABLE ALTERNATIVE LOW HEAT TRANSMISSION AND FIRE-RESISTANT MATERIAL FOR BUILDINGS

2021 ◽  
Vol 11 (3) ◽  
pp. 45-56
Author(s):  
Martin Ernesto Kalaw ◽  
Joshua Martin Kalaw ◽  
Michael Angelo Promentilla
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Fire Resistance ◽  
Coal Fly Ash ◽  
Rice Hull ◽  
Sodium Perborate ◽  
Rice Hull Ash ◽  
Type Specimens ◽  
Foaming Agents ◽  
Mix Proportion

Geopolymers are formed from alumina and silica rich materials by alkali dissolution and subsequent polycondensation into a polymeric network. Geopolymerization technology presents a great potential for positive environmental impact since many alumina- and silica- rich industrial waste materials, such as coal ashes, blast furnace slags, mine tailings, etc., can be used as its precursor materials in a process that requires less energy and gives up less emissions vis-à-vis the current conventional OPC (ordinary Portland cement) technology. In this study, geopolymer samples were prepared using an 85% coal fly ash (CFA) - 10% coal bottom ash (CBA) - 5% rice hull ash (RHA) wt/wt mix proportion and activated using an alkali solution of NaOH-Na2SiO3 at an 80%-20% wt/wt solid-to-liquid ratio. With this mix proportion, two types of specimens were used, a slab type with 50 mm thickness, and a cube type, 50 mm x 50 mm x 50 mm. The slab type specimens were used for evaluating fire resistance using ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials, and the cube type specimens were used to study the effect of foaming agents on the strength and thermal conductivity of the geopolymers formed. Two types of foaming agents, hydrogen peroxide and sodium perborate, at an amount of 0.1% to 0.4% of dry mass mixture, were used. Results from the foamed geopolymers gave compressive strength values ranging from 0.37 to 0.71 MPa and densities of 1430-1560 kg/m3 at 0.3% to 0.4% peroxide added. Values of thermal conductivity of the foamed geopolymers were within 0.033-0.037 W/m-K for all foamed geopolymer samples tested which is a significant reduction compared to the thermal conductivity of the unfoamed geopolymer sample at 0.48 W/m-K. The fire resistance tests show that the unfoamed geopolymer samples perform better than OPC concrete. However, the foamed geopolymers have very low strength compared to the unfoamed sample compressive strength of 18.1 MPa and, thus, are suitable for non-load bearing, insulation applications.

scholarly journals Mechanical and Thermal Properties of Geopolymers from Mixtures of Coal Ash and Rice Hull Ash using Water Glass Solution as Activator

2016 ◽  
Vol 15 (2) ◽  
pp. 51 ◽  
Author(s):  
Martin Ernesto L. Kalaw ◽  
Alvin B Culaba ◽  
Hoc Thang Nguyen ◽  
Khoi Nguyen ◽  
Hirofumi Hinode ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
High Temperature ◽  
Mass Loss ◽  
Water Absorption ◽  
Residential Buildings ◽  
Coal Ash ◽  
Rice Hull ◽  
Rice Hull Ash ◽  
Temperature Exposure

Geopolymers, from industrial wastes such as blast furnace slag, red mud, and coal ash, among others, have emerged as technically viable, economically competitive, and environmentally attractive supplements and even alternatives to ordinary Portland cement (OPC). Furthermore, while the most impact shall be achieved with large-scale use in the general building and structural sector, as replacement or supplement to OPC, the properties of these geopolymers may be optimized for special niche applications. One of these applications is for light weight, low thermal conductivity, heat resistant, and moderate strength cement binder for low rise residential buildings. In this study, compressive strength, heat resistance, volumetric weight, mass loss, water absorption and thermal conductivity of geopolymers formed from mixtures of coal bottom ash and rice hull ash (CBA-RHA) and coal fly ash and rice hull ash (CFA-RHA) with sodium silicate solution (modulus 2.5) as activator were evaluated. Using mixture design and the JMP statistical software, the CBA-RHA combination at a mass ratio of 46% CBA, 32% RHA with 22% WGS gave properties at maximum desirability of 17.6 MPa compressive strength, 1640 kg/m3 volumetric weight, 273 kg/m3 water absorption, 28 MPa compressive strength after high temperature exposure (1000oC for 2 hours) with 4.4% mass loss, and 0.578 W/m-K thermal conductivity. On a performance basis, even as the geopolymers are formed as paste, these properties fall within the standards for lightweight OPC based-concrete with strength requirements for residential buildings. The low thermal conductivity and higher strength after high temperature exposure vis-à-vis OPC are additional advantages for consideration.

A Study on Chemical Foaming Geopolymer Building Materials

2013 ◽  
Vol 853 ◽  
pp. 202-206 ◽  
Author(s):  
Tsung Yin Yang ◽  
Chuan Chi Chien
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Sound Absorption ◽  
Building Materials ◽  
Reaction Rate ◽  
Hydrogen Gas ◽  
Aluminum Powders ◽  
Foaming Agents ◽  
Low Thermal Conductivity ◽  
Base Solution

Zinc and aluminum powders were used as foaming agents and organosilane was innovatively used as a modifier to synthesize a foamed geopolymer. The produced foamed geopolymer with enhanced compressive strength and low thermal conductivity is an ideal material for fire protection, sound absorption and thermal insulation. The low thermal conductivity was achieved by increasing the porosity in the foamed geopolymer and the enhanced compressive strength was realized by adding the modifier. The pore numbers in the foamed geopolymer were greatly increased by releasing the hydrogen gas, which was produced from the chemical reaction of zinc and aluminum powders in a base solution. The modifier decreased the foaming reaction rate and generated homogeneously-distributed small pores in the foamed geopolymer with improved compressive strength.

Freeze-Thaw Resistance of Concrete Modified by Rice Hull Ash and Gangue

2014 ◽  
Vol 488-489 ◽  
pp. 700-703
Author(s):  
Jing Yun Han ◽  
Liang Liang Zhang ◽  
Hai Yang Zhang
Keyword(s):  
Compressive Strength ◽  
Research Work ◽  
Environmental Problems ◽  
Rice Hull ◽  
Rice Hull Ash ◽  
Freeze Thaw ◽  
Concrete Production ◽  
The Cost ◽  
Control Samples

Currently, most rice hull is piled up or burned naturally, resulting in many environmental problems. It is a potentially good way to incinerate specially rice hull into the ash that is used as concrete admixture. The research work was done and results indicate that the compressive strength of the concrete with addition of 1%, 2% and 3% of rice hull ash increased by 6.8%16.7% and 15.1% respectively compared with control samples. And the compound addition of rice hull ash and gangue not only improved the mechanical and anti-freeze-thaw properties of concrete, but also decreased the cost of concrete production.

scholarly journals Utilization of Coal Fly Ash and Rice Hull Ash as Geopolymer Matrix-cum-Metal Dopant Applied to Visible-Light-Active Nanotitania Photocatalyst System for Degradation of Dye in Wastewater

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 240 ◽  
Author(s):  
Eiza Shimizu ◽  
Michael Angelo Promentilla ◽  
Derrick Ethelbhert Yu
Keyword(s):  
Fly Ash ◽  
Visible Light ◽  
Dye Degradation ◽  
Coal Fly Ash ◽  
Rice Hull ◽  
Rice Hull Ash ◽  
Waste Products ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Visible Light Active

Geopolymer (GP) spheres made from coal fly ash (FA) and rice hull ash (RHA) waste products are utilized as both support matrix and dopant applied to titania (TiO2) photocatalyst for organic dye degradation in wastewater. Processing of FA and RHA via suspension-solidification method resulted in GP spheres with nanoporous morphology. The nanocrevices enabled low-energy sol-gel TiO2 coating technique because they served as anchoring sites on the geopolymer surface that favored rigidity and larger surface area. The GP-TiO2 system has been characterized by infrared spectroscopy, X-ray diffraction and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. Diffuse reflectance spectroscopy revealed a narrowing of the GP-TiO2 system optical band gap due to the interaction of metal dopants contained in RHA and FA with TiO2, thus making the GP-TiO2 system a visible-light-active photocatalyst, as confirmed by methylene blue dye degradation measured through UV-Vis spectroscopy.

Manufacturing parameters influencing fire resistance of geopolymers: A review

2016 ◽  
Vol 233 (4) ◽  
pp. 721-733
Author(s):  
Ikmal Hakem Aziz ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Heah Cheng Yong ◽  
Liew Yun Ming ◽  
Kamarudin Hussin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
High Temperature ◽  
Thermal Behavior ◽  
High Temperatures ◽  
Fire Resistance ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Technological Parameters ◽  
Manufacturing Parameters

Geopolymers exhibit various unique properties and characteristics, including high compressive strength, high temperature stability, and low thermal conductivity. As a relatively new and perspective material, the behavior of geopolymers subjected to high temperatures is being intensively studied nowadays. This review summarizes the recent achievements in the development of geopolymer-based fire resistance materials. Technological parameters, which influence thermal behavior of geopolymer-based materials, are also discussed. Besides that, recent applications of geopolymers according to their composition are presented.

scholarly journals Adequate Correlation between the Physical and Mechanical Properties of Glass Foam

2021 ◽  
Vol 1 (4) ◽  
pp. 14-26
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Marius Florin Dragoescu ◽  
Felicia Cosmulescu
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermal Insulation ◽  
Coal Fly Ash ◽  
Physical And Mechanical Properties ◽  
Ceramic Foam ◽  
Glass Waste ◽  
Glass Foam

The paper presents experimental results obtained in the manufacturing process of a glass foam by adequate correlation between its physical and thermal properties (density, porosity, thermal conductivity) and mechanical (compressive strength) by a slight controlled overheating of the foamed material. Using a powder mixture of glass waste (87-91.5 %), coal fly ash (3-9 %) and silicon carbide (4-5.5 %) microwave heated at 935-975 ºC by this unconventional technique, constituting the originality of the work, was obtained a glass-ceramic foam with moderate compressive strength (1.8-2.6 MPa) and very low thermal conductivity (0.058-0.070 W/m·K). The material overheating generated a homogeneous porous structure characterized by closed cells with relatively large dimensions (without the tendency to join neighboring cells) making it difficult to transfer heat across the material. The foamed product is suitable for the manufacture of thermal insulation blocks for the inner or outer walls of the building without excessive mechanical stress, being an advantageous alternative by comparison with known types of polymeric or fiberglass thermal insulation materials.

scholarly journals Fabrication and Fireproofing Performance of the Coal Fly Ash-Metakaolin-Based Geopolymer Foams

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1750 ◽  
Author(s):  
Xi Peng ◽  
Qin Shuai ◽  
Han Li ◽  
Qin Ding ◽  
Yan Gu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Physical Properties ◽  
Fire Resistance ◽  
Coal Fly Ash ◽  
Structure Stability ◽  
Dry Density ◽  
Porous Blocks ◽  
Resistance Tests ◽  
Skeleton Structure

This paper aims to investigate the influence of coal fly ash (CFA) addition on the fireproof properties of the metakaolin-based geopolymer foams. The physical properties, thermal conductivity and fire resistance of the CFA-metakaolin-based geopolymer foams are discussed. The CFA-metakaolin-based geopolymer foams achieve a dry density between 259.43 kg/m3 and 349.73 kg/m3, a porosity between 71.78% and 72.98%, a thermal conductivity between 0.0871 W/(m·K) and 0.0944 W/(m·K) and a compressive strength between 0.38 MPa and 0.56 MPa, exhibiting better physical properties than that of the porous blocks without CFA addition. It is also found that the CFA addition could decrease the viscous sintering temperature and change the phase compositions of sintering products, resulting in the porous structure deterioration in a certain extent and obvious rise of the final reverse-side temperature during the fire-resistance tests. Fortunately, the conversion of the amorphous geopolymer gel to ceramics has helped to maintain the main skeleton structure stability. The CFA-metakaolin-based geopolymer foams still exhibit excellent fire resistance, and the reverse-side temperatures are always within 250 °C after 3 h fire-resistance tests.

scholarly journals Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

Materials ◽  
2016 ◽  
Vol 9 (7) ◽  
pp. 580 ◽  
Author(s):  
Martin Kalaw ◽  
Alvin Culaba ◽  
Hirofumi Hinode ◽  
Winarto Kurniawan ◽  
Susan Gallardo ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Rice Hull ◽  
Ternary Blend ◽  
Rice Hull Ash ◽  
Coal Bottom Ash

scholarly journals New Manufacturing Method of Glass Foam by Cold Expansion of Glass Waste

2021 ◽  
Vol 2 (3) ◽  
pp. 1-9
Author(s):  
Lucian Paunescu ◽  
Sorin Mircea Axinte ◽  
Bogdan Valentin Paunescu
Keyword(s):  
Thermal Conductivity ◽  
Aqueous Solution ◽  
Compressive Strength ◽  
High Temperature ◽  
Insulation Material ◽  
Glass Waste ◽  
Foaming Agents ◽  
Manufacturing Method ◽  
Aluminium Powder ◽  
Glass Foam

Abstract                                                         An innovation cold manufacturing method of glass foams is presented in the paper. Traditional foaming agents used in conventional expansion processes of glass waste at high temperature were substituted with aluminium powder in aqueous solution of calcium hydroxide, which releases hydrogen forming gas bubbles in the viscous sludge and then, by solidification, a porous structure typical for the glass foam. The manufactured foam is adequate for using as a thermal insulation material for inner wall of buildings, having the apparent density of 0.31 g·cm-3, the thermal conductivity of 0.070 W/m·K and the compressive strength of 1.32 MPa. The process originality is the use of recycled aluminum waste, melted by an own microwave heating technique and sprayed with nitrogen jets. The process effectiveness is remarkable in economical and energy terms.

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