Mechanical strength of experimental mortars for plastering with partial addition of fly ash and hydrated lime

Novel hemp fiber reinforced geopolymer composites were fabricated. The matrix was a new geopolymer based on a mixture of red mud and fly ash. Chopped, randomly oriented hemp fibers were used as reinforcement. The mechanical properties of the geopolymer composite, such as diametral tensile (DTS) (or Brazilian tensile) strength and compressive strength (CS), were measured. The geopolymer composites reinforced with 9 vol.% and 3 vol.% hemp fiber yielded average DTS values of 5.5 MPa and average CS values of 40 MPa. Scanning electron microscopy (SEM) studies were carried out to evaluate the microstructure and fracture surfaces of the composites. The results indicated that the addition of hemp fiber is a promising approach to improve the mechanical strength as well as to modify the failure mechanism of the geopolymer, which changed from brittle to “pseudo-ductile”.

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HYDRATED LIME PASTES CONTAINING COAL-FLY ASH AND POLYAMINOPHENOLIC ADDITIVES FOR THE INERTIZATION OF FLY ASHES FROM MUNICIPAL SOLID WASTES INCINERATORS

Challenges of Concrete Construction: Volume 5, Sustainable Concrete Construction ◽

10.1680/scc.31777.0014 ◽

2002 ◽

pp. 139-150

Author(s):

G Rinaldi ◽

F Medici

Keyword(s):

Fly Ash ◽

Coal Fly Ash ◽

Hydrated Lime ◽

Solid Wastes ◽

Fly Ashes ◽

Municipal Solid Wastes

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Influence of low-temperature curing on the mechanical strength, hydration process, and microstructure of alkali-activated fly ash and ground granulated blast furnace slag mortar

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.121811 ◽

2021 ◽

Vol 269 ◽

pp. 121811

Author(s):

Xiaobin Wei ◽

Dongqing Li ◽

Feng Ming ◽

Chengsong Yang ◽

Lei Chen ◽

...

Keyword(s):

Blast Furnace ◽

Fly Ash ◽

Low Temperature ◽

Mechanical Strength ◽

Blast Furnace Slag ◽

Hydration Process ◽

Granulated Blast Furnace Slag ◽

Furnace Slag ◽

Alkali Activated

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The Effect of MIRHA and Fly Ash on Mechanical Strength and Chloride Penetration Depth of DSCC

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.567.522 ◽

2014 ◽

Vol 567 ◽

pp. 522-528

Author(s):

Muhd Fadhil Nuruddin ◽

Kok Yung Chang ◽

Norzaireen Mohd Azmee

Keyword(s):

Fly Ash ◽

Mechanical Strength ◽

Penetration Depth ◽

Rice Husk Ash ◽

Chloride Penetration ◽

Advanced Materials ◽

Ternary Blends ◽

Self Compacting Concrete ◽

Chloride Permeability ◽

Positive Effects

Ductile self-compacting concrete (DSCC) is one of the advanced materials which combines self-compacting abilities and ductility to address the current industry problems. As the fly ash and microwave incinerated rice husk ash (MIRHA) are beneficial to the properties of concrete, it has led to a research on the effects of ternary blends of MIRHA, fly ash and cement in DSCC. Up to 20% of cement in DSCC was replaced with MIRHA and fly ash with 10% by weight respectively whilst maintaining satisfactory self-compacting abilities. The effects of MIRHA and fly ash on mechanical strength and chloride penetration depth of DSCC were determined. The control DSCC mix was compared with the DSCC mix with MIRHA and fly ash. The results shown that substitution of MIRHA and fly ash into DSCC gave positive effects, it improved the mechanical properties and chloride permeability.

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Water-Resistant Modification of Desulphurization Gypsum Block

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.182-183.278 ◽

2012 ◽

Vol 182-183 ◽

pp. 278-282

Author(s):

Yan Mu ◽

Ying Li Fu ◽

Feng Qing Zhao

Keyword(s):

Fly Ash ◽

Mechanical Strength ◽

High Performance ◽

Water Resistance ◽

Curing Temperature ◽

Curing Time ◽

Operating Property ◽

High Mechanical Strength ◽

Calcined Gypsum ◽

Hemi Hydrate

A high performance water resistance agent KD-3 prepared from OPC cement, fly ash, slag and additives was used for the modification of hemi-hydrate desulphurization gypsum. Various factors on gypsum block were investigated. The prepared gypsum block possesses excellent water-resistance, good operating property and high mechanical strength. The optimized results was obtained: calcined gypsum 74.9%, KD-3 25%, retarder 0.1%, curing temperature 60°C and curing time 16h.

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Potential for Developing Biocarbon Briquettes for Foundry Industry

Applied Sciences ◽

10.3390/app9245288 ◽

2019 ◽

Vol 9 (24) ◽

pp. 5288 ◽

Cited By ~ 1

Author(s):

Elsayed Mousa ◽

Mania Kazemi ◽

Mikael Larsson ◽

Gert Karlsson ◽

Erik Persson

Keyword(s):

Tensile Strength ◽

Energy Density ◽

Mechanical Strength ◽

Compaction Pressure ◽

Hydrated Lime ◽

Hydraulic Press ◽

Ash Content ◽

Heating Value ◽

Cupola Furnace ◽

Foundry Industry

The foundry industry is currently facing challenges to reduce the environmental impacts from application of fossil fuels. Replacing foundry coke with alternative renewable carbon sources can lead to significant decrease in fossil fuel consumption and fossil CO2 emission. The low bulk density, low energy density, low mechanical strength and the high reactivity of biocarbon materials are the main factors limiting their efficient implementation in a cupola furnace. The current study aimed at designing, optimizing and developing briquettes containing biocarbon, namely, biocarbon briquettes for an efficient use in cupola furnace. Laboratory hydraulic press with compaction pressure of about 160 MPa and stainless-steel moulds (Ø = 40 mm and 70 mm) were used for compaction. The density, heating value, energy density, mechanical strength and reactivity of biocarbon briquettes were measured and evaluated. The compressive strength and splitting tensile strength of biocarbon briquettes were measured by a compression device. The reactivity of biocarbon briquettes was measured under controlled conditions of temperature and gas atmosphere using the thermogravimetric analysis technique (TGA). Different types of binders were tested for the compaction of commercial charcoal fines with/without contribution of coke breeze. The effect of charcoal ratio, particle size, binder type, binder ratio, moisture content and compaction pressure on the quality of the biocarbon briquettes was investigated. Molasses with hydrated lime and cement were superior in enhancing the biocarbon briquettes strength and energy density among other tested binders and additives. The briquettes’ strength decreased as the biocarbon content increased. The optimum recipes consisted of 62% charcoal fines, 20% molasses, 10% hydrated lime and 8% cement. Cement is necessary to develop the tensile strength and hot mechanical strength of the briquettes. The charcoal with high ash content showed higher strength of briquettes but lower heating value compared to that with low ash content. Dispersion of silica suspension on charcoal particles during the mixing process was able to reduce the reactivity of biochar in the developed biocarbon briquettes. The biocarbon briquettes density and strength were increased by increasing the compaction pressure. Commercial powder hydrated lime was more effective in enhancing the briquettes’ strength compared to slaked burnt lime. Upscaling of biocarbon briquettes (Ø = 70 mm) and testing of hot mechanical strength under load indicated development of cracks which significantly reduced the strength of briquettes. Further development of biocarbon briquettes is needed to fulfil the requirements of a cupola furnace.

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Mechanical and Microstructural Characterization of Quarry Rock Dust Incorporated Steel Fiber Reinforced Geopolymer Concrete and Residual Properties after Exposure to Elevated Temperatures

Materials ◽

10.3390/ma14226890 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6890

Author(s):

Muhammad Ibraheem ◽

Faheem Butt ◽

Rana Muhammad Waqas ◽

Khadim Hussain ◽

Rana Faisal Tufail ◽

...

Keyword(s):

Mechanical Properties ◽

Weight Loss ◽

Compressive Strength ◽

Fly Ash ◽

Mechanical Strength ◽

Elevated Temperatures ◽

Strength Properties ◽

Steel Fibers ◽

Geopolymer Concrete

The purpose of this research is to study the effects of quarry rock dust (QRD) and steel fibers (SF) inclusion on the fresh, mechanical, and microstructural properties of fly ash (FA) and ground granulated blast furnace slag (SG)-based geopolymer concrete (GPC) exposed to elevated temperatures. Such types of ternary mixes were prepared by blending waste materials from different industries, including QRD, SG, and FA, with alkaline activator solutions. The multiphysical models show that the inclusion of steel fibers and binders can enhance the mechanical properties of GPC. In this study, a total of 18 different mix proportions were designed with different proportions of QRD (0%, 5%, 10%, 15%, and 20%) and steel fibers (0.75% and 1.5%). The slag was replaced by different proportions of QRD in fly ash, and SG-based GPC mixes to study the effect of QRD incorporation. The mechanical properties of specimens, i.e., compressive strength, splitting tensile strength, and flexural strength, were determined by testing cubes, cylinders, and prisms, respectively, at different ages (7, 28, and 56 days). The specimens were also heated up to 800 °C to evaluate the resistance of specimens to elevated temperature in terms of residual compressive strength and weight loss. The test results showed that the mechanical strength of GPC mixes (without steel fibers) increased by 6–11%, with an increase in QRD content up to 15% at the age of 28 days. In contrast, more than 15% of QRD contents resulted in decreasing the mechanical strength properties. Incorporating steel fibers in a fraction of 0.75% by volume increased the compressive, tensile, and flexural strength of GPC mixes by 15%, 23%, and 34%, respectively. However, further addition of steel fibers at 1.5% by volume lowered the mechanical strength properties. The optimal mixture of QRD incorporated FA-SG-based GPC (QFS-GPC) was observed with 15% QRD and 0.75% steel fibers contents considering the performance in workability and mechanical properties. The results also showed that under elevated temperatures up to 800 °C, the weight loss of QFS-GPC specimens persistently increased with a consistent decrease in the residual compressive strength for increasing QRD content and temperature. Furthermore, the microstructure characterization of QRD blended GPC mixes were also carried out by performing scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS).

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High Volume Fly Ash Self Compacting Concrete with Lime and Silica Fume as Additives

E3S Web of Conferences ◽

10.1051/e3sconf/202018401109 ◽

2020 ◽

Vol 184 ◽

pp. 01109

Author(s):

C Chandana Priya ◽

M V Seshagiri Rao ◽

V Srinivasa Reddy ◽

S Shrihari

Keyword(s):

Fly Ash ◽

Calcium Hydroxide ◽

Silica Fume ◽

High Volume ◽

Hydrated Lime ◽

Pozzolanic Reaction ◽

Self Compacting Concrete ◽

Conventional Concrete ◽

High Volume Fly Ash ◽

Reactive Silica

SCC is expensive when compared with normal conventional concrete. Hence, it is desired to produce low cost SCC by replacing cement with higher percentages of fly ash, which is a no cost material and available in abundance. At the same time to achieve higher grade HVFASCC, micro silica which is otherwise condensed silica fume can also be used along with fly ash to enhance the strength properties of HVFASCC. By replacing fly ash in high volumes in the mix, high amount of pozzolanic material becomes available, majorly reactive silica, for which more calcium hydroxide is necessary for further pozzolanic reaction. As we are reducing cement quantity, the amount of calcium hydroxide available is reduced thus demanding external addition of hydrated lime which can be supplied as additive to cater to the need of calcium hydroxide required for reactive silica in fly ash.The present investigation aims to achieve strength for high volume fly ash self-compacting concrete. The replacement of cement with fly ash is made in 45%, 50%, 55%, 60%, 65% and 70% with 20% hydrated lime and 10% silica fume in one trial. In another trial, 30% hydrated lime and 10% silica fume is added with replacement of fly ash to cement varying in same percentages. The design mix is tested for workability and flowability and cubes are casted for compression strength test and tested at 28 day,, 56 day, and 90 day,.

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