The use of coal fly ash in concrete for marine artificial reefs in the southeastern Mediterranean: compressive strength, sessile biota, and chemical composition

Dense ceramics are produced from fly ash from REK Bitola, Republic of Macedonia. Four types of fly ash from electro filters and one from the collected zone with particles < 0.063 mm were the subject of this research. Consolidation was achieved by pressing (P= 133 MPa) and sintering (950, 1000, 1050 and 11000C and heating rates of 3 and 100/min). Densification was realized by liquid phase sintering and solid state reaction where diopside [Ca(Mg,Al)(Si,Al)2O6] was formed. Ceramics with optimal properties (porosity 2.96?0.5%, bending strength - 47.01?2 MPa, compressive strength - 170 ?5 MPa) was produced at 1100?C using the heating rate of 10?C/min.

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An Investigation of Usability of Brown Coal Fly Ash for Building Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.30 ◽

2013 ◽

Vol 438-439 ◽

pp. 30-35 ◽

Cited By ~ 2

Author(s):

Nirdosha Gamage ◽

Sujeeva Setunge ◽

Kasuni Liyanage

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Brown Coal ◽

Water Contamination ◽

Building Materials ◽

Coal Fly Ash ◽

Sustainable Building ◽

Laboratory Investigations ◽

Cold Pressed ◽

Initial Results

The Victoria State of Australia has the second largest reserves of brown coal on earth, representing approximately 20% of the worlds reserves, and at current use, could supply Victoria with its energy for over 500 years. Its combustion, annually, yields up to 1.3 million tonnes of fly ash, which is largely use for land-fills. Disposal of fly ash in open dumps cause massive environmental problems such as ground water contamination that may create various health problems. This study focuses on the usability of brown coal fly ash to develop a sustainable building material. A series of laboratory investigations was conducted using brown coal fly ash combined with cement and aggregate to prepare cold pressed samples aiming to test their properties. Initial results indicate that compressive strength satisfies minimum standard compressive strength required for bricks or mortar.

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The Effect of Substituting Rdf on the Physical and Environmental Properties of Coal Fly Ash

MRS Proceedings ◽

10.1557/proc-136-223 ◽

1988 ◽

Vol 136 ◽

Author(s):

Ashaari B. Mohamad ◽

David L. Gress

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Physical Properties ◽

Activity Index ◽

Coal Fly Ash ◽

Pozzolanic Activity ◽

Portland Cement Concrete ◽

Fly Ash Concrete ◽

Refuse Derived Fuel ◽

Cadmium And Lead

ABSTRACTRefuse-derived-fuel (RDF) consisting mainly of waste paper and plastics is a viable fuel source for the production of power. An experimental test burn partially substituting coal with RDF was undertaken by the Public Service of New Hampshire at the Merrimack Power Station.Five percent and ten percent RDF were substituted, on a BTU basis, for coal in the test bums. The chemical and physical properties of the resulting fly ash were determined. Twelve test burn days were run with 4 days of 5% RDF and 8 days of 10% RDF. Emphasis was placed on investigating the effect of the RDF fly ash on Portland cement concrete.Most of the chemical and physical properties of the coal-RDF fly ash were found to be comparable with ordinary coal fly ash except for the amount of cadmium and lead, the pozzolanic activity index and the compressive strength of fly ash concrete. Cadmium and lead were at average levels of 5.1 ppm and 102.6 ppm for the 5% RDF, and 7.8 ppm and 198.3 ppm for the 10% RDF, respectively. Although the pozzolanic activity index of coal-RDF fly ash increases over normal coal fly ash, preliminary results show that the 28-day compressive strength of concrete with direct replacement of cement and sand decreases by up to 30%. Leaching tests on crushed concrete were conducted to evaluate the environmental effect of acid rain.

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Utilization of Electroplating Sludge as Subgrade Backfill Materials: Mechanical and Environmental Risk Evaluation

Advances in Civil Engineering ◽

10.1155/2018/4891418 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Yu Zhang ◽

Peixin Shi ◽

Lijuan Chen ◽

Qiang Tang

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Water Content ◽

Environmental Risk ◽

Coal Fly Ash ◽

Surrounding Environment ◽

Electroplating Sludge ◽

Backfill Materials ◽

Standard Limit ◽

The Impact

The electroplating sludge may pose serious threat to human health and surrounding environment without safe treatment. This paper investigated the feasibility of using electroplating sludge as subgrade backfill materials, by evaluating the mechanical properties and environmental risk of the cement-coal fly ash solidified sludge. In this study, Portland cement and coal fly ash are used to solidify/stabilize the sludge. After curing for 7, 14, and 28 days, the stabilization/solidification sludge specimens were subject to a series of mechanical, leaching, and microcosmic tests. It was found that the compressive strength increased with the increase of cement content, curing time, and the cement replacement by coal fly ash besides water content. Among these factors, the impact of water content on the compressive strength is most noticeable. It was observed that the compressive strength declined by 87.1% when the water content increased from 0% to 10%. Besides, leaching tests showed that the amount of leaching heavy metals were under the standard limit. These results demonstrated utilization of electroplating sludge in subgrade backfill material may provide an alternative for the treatment of electroplating sludge.

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Compressive strength and microstructure evolution of low calcium brown coal fly ash-based geopolymer

Journal of Sustainable Cement-Based Materials ◽

10.1080/21650373.2019.1666061 ◽

2019 ◽

Vol 9 (1) ◽

pp. 17-34 ◽

Cited By ~ 6

Author(s):

Muhamed Khodr ◽

David W. Law ◽

Chamila Gunasekara ◽

Sujeeva Setunge ◽

Robert Brkljaca

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Brown Coal ◽

Microstructure Evolution ◽

Coal Fly Ash ◽

Low Calcium

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Compressive strength and hydration of high-volume wet-grinded coal fly ash cementitious materials

Construction and Building Materials ◽

10.1016/j.conbuildmat.2019.02.038 ◽

2019 ◽

Vol 206 ◽

pp. 248-260 ◽

Cited By ~ 21

Author(s):

Hongbo Tan ◽

Kangjun Nie ◽

Xingyang He ◽

Xiufeng Deng ◽

Xun Zhang ◽

...

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Coal Fly Ash ◽

High Volume ◽

Cementitious Materials

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Utilization of Fly Ash with Higher Loss on Ignition for Geopolymer Mortar

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1129.614 ◽

2015 ◽

Vol 1129 ◽

pp. 614-620

Author(s):

Yasutaka Sagawa ◽

Shu Ota ◽

Koji Harada ◽

Takeyoshi Nishizaki ◽

Hiroki Goda

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Coal Fly Ash ◽

Drying Shrinkage ◽

Silicate Material ◽

Loss On Ignition ◽

Heat Curing ◽

Higher Temperature ◽

Curing Condition ◽

Class F Fly Ash

In this study, utilization of coal fly ash with higher loss on ignition (LOI) for geopolymer mortar was investigated. The fly ash with approximately 9% of LOI was compared with Class F fly ash. Relationship between heat curing condition and strength was clarified. As the results, although compressive strength of geopolymer mortar with higher LOI was 30-50% smaller, it was available for geopolymer mortar as an alumina silicate material. The higher temperature and the longer period for initial curing, the higher strength was obtained. In order to decrease drying shrinkage, the higher temperature and the longer period for heat curing were required.

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Possibilities of Using Alternative Materials as a Substitute Binder or Filler into Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1105.31 ◽

2015 ◽

Vol 1105 ◽

pp. 31-35 ◽

Cited By ~ 1

Author(s):

Nadežda Števulová ◽

Ivana Schwarzova ◽

Viola Hospodarova ◽

Jozef Junak ◽

Marcela Ondova ◽

...

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Coal Fly Ash ◽

Steel Slag ◽

Recycled Concrete ◽

Partial Replacement ◽

Alternative Materials ◽

Activated Coal ◽

Hemp Fibres ◽

Lightweight Composites

This article reports on the possibilities of using selected alternative materials like hemp fibres, MgO-cement, recycled concrete, fly ash and steel slag as binder or filler replacement in composite materials in civil engineering production. These binder or filler substitutes were mixed into composites and their compressive strength was tested. The paper is divided into four parts providing the results of experiments. In first part strength parameters of lightweight composites based on natural fibres (hemp hurds) and alternative binder (MgO-cement) are presented. Compressive strength values of concrete samples with partial replacement of cement with mechanochemically activated coal fly ash are given. The third and forth part is aimed to utilization of recycled concrete and steel slag as a natural aggregate replacement in concrete mixture for purpose of structural concrete and surface roads.

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Development of Inorganic Binder with MSWI Ash

Materials Science Forum ◽

10.4028/www.scientific.net/msf.569.317 ◽

2008 ◽

Vol 569 ◽

pp. 317-320

Author(s):

Woo Keun Lee ◽

Eun Zoo Park ◽

Young Do Kim ◽

Se Gu Son ◽

Ji Hyeon Lee

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Coal Fly Ash ◽

Environmental Safety ◽

Waste Incinerator ◽

Geopolymer Concrete ◽

Inorganic Binder ◽

Active Filler ◽

Mineral Phases ◽

Solid Waste Incinerator

Municipal Solid Waste Incinerator (below MSWI) ash is used to develop inorganic binder for preparing geopolymer concrete in this study. Toxic substituents, such as heavy metals are de-toxificated by above-mentioned new solidity technique. Slag and coal fly ash are used as active filler to enhance compressive strength. MSWI ash was mixed with slag and coal fly ash to make geopolymer concrete. They were solidified under alkali condition and dried at 50°C and 80°C, respectively. Compressive strength was measured to evaluate the characteristics of specimens for the period of 3, 7 and 14 days. Compressive strength measurements show a maximum strength of almost 13.7 MPa after 14 days. The mineral phases of specimen were analyzed by XRD. And the morphology was analyzed by the photo of SEM. The micro-structure of inorganic binder prepared was analyzed by FTIR. Korea Standard leaching Test (KSLT) and TCLP method are used to the environmental safety of inorganic binder. Raw FA measured concentrations of Cu and Pb were 0.30 ppm and 28.31 ppm, respectively. Leaching amounts of heavy metal were noticeably reduced after the solidification of MSWI as with active filler. It is possible to de-toxificate MSWI ash by new solidity techniques. And it may be used as alternative concrete.

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Effect of Dipotassium Hydrogen Phosphate and Calcium Nitrate on Strength and Microstructural Properties of Geopolymer Mortar

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.821.486 ◽

2019 ◽

Vol 821 ◽

pp. 486-492

Author(s):

Norbaizurah Rahman ◽

Amalina Hanani Ismail ◽

Andri Kusbiantoro

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Coal Fly Ash ◽

Setting Time ◽

Relevant Literature ◽

Calcium Nitrate ◽

Microstructural Properties ◽

Hydrogen Phosphate ◽

Strength Performance ◽

Dipotassium Hydrogen Phosphate

Adoption of coal fly ash (Class C) as the main source material for geopolymers would cause rapid setting to the fresh geopolymer mortar or concrete. This behaviour explained the limited application of this material in the construction industry. On the other hand, calcium nitrate (Ca (NO3)2) and dipotassium hydrogen phosphate (K2HPO4) are alternative admixtures that known to extend the setting time of fresh geopolymers. However, their effect on the strength and microstructural properties remain unclear due to the limitation of relevant literature from previous studies. Therefore, this study aims to investigate the effect of these admixtures in fly ash based geopolymer system, particularly to its strength performance. The effects of adding Ca (NO3)2 and K2HPO4 were evaluated at dosages of 0.5%, 1.5%, and 2.5% (by fly ash weight) in the geopolymer mixture, and samples were cured at room temperature. Hardened geopolymer specimens were measured for their compressive strength, porosity, and microstructural characteristic. The inclusion of 0.5% of alternative chemical reagents was found as the optimum proportion and able to enhance the compressive strength of the geopolymer mixtures. However, efflorescence was detected on the surface of the hardened specimen when K2HPO4 was included in its mixture. This phenomenon is influenced by the presence of monovalent and trivalent anions in the system namely nitrates and phosphates. In this study, each anion had a particular role in each stage of geopolymerisation, and determined the quality via crystal growth control and influenced the development of aluminosilicate structures.

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