Engineering properties of cement mortar with pond ash in South Korea as construction materials: from waste to concrete

2013 ◽  
Vol 3 (3) ◽  
Author(s):  
Sang Jung ◽  
Seung-Jun Kwon

AbstractAmong the wastes from coal combustion product, only fly ash is widely used for mineral mixture in concrete for its various advantages. However the other wastes including bottom ash, so called PA (pond ash) are limitedly reused for reclamation. In this paper, the engineering properties of domestic pond ash which has been used for reclamation are experimentally studied. For this, two reclamation sites (DH and TA) in South Korea are selected, and two domestic PAs are obtained. Cement mortar with two different w/c (water to cement) ratios and 3 different replacement ratios (0%, 30%, and 60%) of sand are prepared for the tests. For workability and physical properties of PA cement mortar, several tests like flow, setting time, and compressive strength are evaluated. Several durability tests including porosity measuring, freezing and thawing, chloride migration, and accelerated carbonation are also performed. Through the tests, PA (especially from DH area) in surface saturated condition is evaluated to have internal curing action which leads to reasonable strength development and durability performances. The results show a potential applicability of PA to concrete aggregate, which can reduce consuming natural resources and lead to active reutilization of coal product waste.

1989 ◽  
Vol 178 ◽  
Author(s):  
Kirsten G. Jeppesen

AbstractSpray dried absorption products (SDA) having special characteristics are used as substitutes for cement in the preparation of mortars; the qualities of the resulting mixed mortars are described. Conditions are described for mortar mixes, data for which were presented at the MRS Fall Meeting 1987.The influence of the composition of the SDA on water requirement and setting time has been studied. A full scale project involving 3 precast, reinforced concrete front-elements containing 20 and 30 wt.% SDA is described. Strength development, mineralogical composition and corrosion were monitored for two years.A non-standard freeze-thaw experiment was performed which compares mortars containing SDA and fly ash (FA) and also shows the effect of superplasticizer.The possibility of improving the SDA by grinding has been tested and a limited improvement has been found. The strength of the mixed mortars seems slightly influenced by the grain size of SDAGypsum (CaSO4·2H2O), synthetic calcium-sulphite (CaSO3·½H2O) and 2 SDAs have been used as retarders for cement clinker. Mortar test prisms have been cast and comparative strengths after curing for 3 years are reported


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1927
Author(s):  
Lei Jin ◽  
Guodong Huang ◽  
Yongyu Li ◽  
Xingyu Zhang ◽  
Yongsheng Ji ◽  
...  

Setting time and mechanical properties are key metrics needed to assess the properties of municipal solid waste incineration (MSWI) bottom ash alkali-activated samples. This study investigated the solidification law, polymerization, and strength development mechanism in response to NaOH and liquid sodium silicate addition. Scanning electron microscopy and X-ray diffraction were used to identify the formation rules of polymerization products and the mechanism of the underlying polymerization reaction under different excitation conditions. The results identify a strongly alkaline environment as the key factor for the dissolution of active substances as well as for the formation of polymerization products. The self-condensation reaction of liquid sodium silicate in the supersaturated state (caused by the loss of free water) is the major reason for the rapid coagulation of alkali-activated samples. The combination of both NaOH and liquid sodium silicate achieves the optimal effect, because they play a compatible coupling role.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6654
Author(s):  
Jakub Popławski ◽  
Małgorzata Lelusz

Biomass combustion is a significant new source of green energy in the European Union. The adequate utilization of byproducts created during that process is a growing challenge for the energy industry. Biomass fly ash could be used in cement composite production after appropriate activation of that material. This study had been conducted to assess the usefulness of mechanical and physical activation methods (grinding and sieving), as well as activation through the addition of active silica in the form of silica fume, as potential methods with which to activate biomass fly ash. Setting time, compressive strength, water absorption and bulk density tests were performed on fresh and hardened mortar. While all activation methods influenced the compressive strength development of cement mortar with fly ash, sieving of the biomass fly ash enhanced the early compressive strength of cement mortar. The use of active silica in the form of silica fume ensured higher compressive strength results than those of control specimens throughout the entire measurement period.


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3143
Author(s):  
Byoung Hooi Cho ◽  
Boo Hyun Nam ◽  
Jinwoo An ◽  
Heejung Youn

Over the past decades, extensive studies on municipal solid waste incineration (MSWI) ashes have been performed to develop more effective recycling and waste management programs. Despite the large amount of research activities and the resulting improvements to MSWI ashes, the recycling programs for MSWI ashes are limited. For instance, although the U.S. generates more MSWI ashes than any other country in the world, its reuse/recycle programs are limited; bottom ash and fly ash are combined and disposed of in landfills. Reuse of MSWI ashes in the construction sectors (i.e., geomaterials, asphalt paving, and concrete products) as replacements for raw materials is one of most promising options because of the large consumption and relatively lenient environmental criteria. The main objective of this study was to comprehensively review MSWI ashes with regard to specific engineering properties and their performance as construction materials. The focus was on (1) the current practices of MSWI ash management (in particular, a comparison between European countries and the U.S.), (2) the engineering properties and performance of ashes when they are used as substitutes of construction materials and for field applications, and (3) the environmental properties and criteria for the use of MSWI ashes. Overall, the asphalt and concrete applications are the most promising, from both the mechanical and leachate viewpoints. However, cons were also observed: high absorption of MSWI ash requires a high asphalt binder content in hot-mix asphalt, and metallic elements in the ash may generate H2 gas in the high-pH environment of the concrete. These side effects can be predicted via material characterization (i.e., chemical and physical), and accordingly, proper treatment and/or modified mix proportioning can be performed prior to use.


2022 ◽  
Vol 8 (1) ◽  
pp. 181-194
Author(s):  
Fanny Monika ◽  
Hakas Prayuda ◽  
Martyana Dwi Cahyati ◽  
Erwiena Nurmala Augustin ◽  
Hilal Aulia Rahman ◽  
...  

Concrete is considered one of the construction materials that contribute the most significant carbon dioxide in the world. Meanwhile, according to various studies, concrete production will continue to rise through 2050, especially in developing countries. According to several reports, cement manufacture is one of the largest sources of carbon dioxide in the concrete sector. In addition, overexploitation of aggregates due to concrete production also causes unavoidable natural damage. Bottom ash waste was used as a replacement for cement and fine aggregate as sustainable construction materials. It is envisaged that this research would allow industrial waste to be utilized to its full potential, resulting in a concrete that is more environmentally friendly and minimizes carbon dioxide emissions during the manufacturing process. This study is divided into bottom ash as a cement substitute and bottom ash as a fine aggregate substitute. The engineering properties of the concrete were checked during the experiments in this study when it was fresh and hardened states. The slump test is used to determine the workability of fresh concrete. While for the hardened properties tests consist of compressive strength, splitting tensile strength, flexural strength, and mass density. The usage of bottom ash as a cement replacement demonstrates that as the composition of bottom ash increases, the performance of the hardened properties of concrete decreases. While using bottom ash as a fine aggregate replacement reveals that the performance of hardened properties has improved as the proportion of bottom ash utilized has increased. Doi: 10.28991/CEJ-2022-08-01-014 Full Text: PDF


2010 ◽  
Vol 658 ◽  
pp. 300-303
Author(s):  
Soo Ryong Kim ◽  
Woo Teck Kwon ◽  
Byung Ik Kim ◽  
Y. Kim ◽  
Sang Wook Ha

The effectiveness of bottom ash on the mechanical and physical properties of lightweight cement mortar for fire proofing application is investigated in this study. Bottom ash is well known that it can make it possible to decrease the thermal conduction in mortar by their porous structure. Physical properties of bottom ash including pozzolanic activity and compressive strength test were measured to decide the replacement amount in formulation as well as chemical composition. This study was undertaken on the use of bottom ash as fine aggregate in fire proofing mortar. Various dosage of bottom ash such as 25%, 50%, 75%, 100% were evaluated by several measurement. We found out there were serious correlation between specific gravity and thermal conductivity, so other porous materials were also investigated to decrease the thermal conductivity of cement mortar as well as bottom ash. In this study, the researches on the mixing proportion were mainly performed to design specification of spraying fire proofing mortar. Based on the laboratory test results, we’d like to suggest the proper adding amount of bottom ash by evaluation of consistency and strength development and then optimum mixing proportions of spraying fire proofing mortar using bottom ash by various evaluations.


2021 ◽  
Author(s):  
Huashan YANG ◽  
Yujun CHE

During recycling waste concrete, a large amount of waste concrete powder (WCP) is generated. However, efficient utilization of WCP remains an unresolved issue. This paper investigates the influences of WCP on the properties and hydration products of cement mortar containing fly ash (FA). This study used two different types of WCPs. One was made from an ordinary Portland cement mortar, and the other was derived from a Portland cement mortar. WCP replaced 10%, 20%, and 30% of FA. The water requirement, setting time, flow index, strength, hydration products, and microstructure of FA mortar incorporating WCP were investigated. Test results indicate that the WCP has no significant influence on the performances and hydration products of FA mortar. By adequately combining WCP and FA, the FA mortar with required performances could be reached.


2001 ◽  
Vol 28 (5) ◽  
pp. 778-786 ◽  
Author(s):  
Caijun Shi

Natural pozzolan is one of the oldest construction materials. Lime-pozzolan cements have been used for several thousands of years and have an excellent reputation for their durability. Pozzolans are being widely used as a cement replacement in Portland cement concrete. The use of pozzolans has the advantage of lower costs and better durability, but the disadvantage of a longer setting time and a slower early strength development. Different techniques have been tried to increase the reactivity of natural pozzolans to overcome these disadvantages. This paper has reviewed various methods used to activate the pozzolanic activity of natural pozzolans. All activation methods can be classified into three catalogues: thermal, mechanical, and chemical activation. A comparison based on strength–cost relationship indicates that the chemical activation method is the most effective and cheapest one.Key words: activation, reactivity, natural pozzolans, pozzolanic reaction, calcination, elevated temperature curing, chemical activators, strength, cost.


1986 ◽  
Vol 86 ◽  
Author(s):  
E. E. Berry ◽  
E. J. Anthony

ABSTRACTThis paper presents a brief review of the literature dealing with utilization of atmospheric-pressure fluidized bed combustion (AFBC) solid wastes. The uses that have been proposed for AFBC residues include the following: agricultural lime, waste neutralization and stabilization, low-strength backfill, soil cementing and asphaltic concrete aggregate. An evaluation of a high-Ca waste from a Canadian AFBC installation is discussed. The waste was found to be unsuitable for applications in Port-land cement concrete because of poor strength development and expansion in mortars. The waste was compatible with Portland cement for soil cementing purposes but the resulting mixes were not resistant to freezing and thawing. Applications in asphaltic concrete were found to be successful in the laboratory and a small field trial is in progress.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Wenbin Xu ◽  
Qianlong Li ◽  
Sada Haruna

The influence of admixtures on the engineering properties of fly ash-based cemented tailings backfill (CTB) is a topic of significant practical interest, as it affects the backfilling cost and the environmental effect of mining operation. This paper presents results of an experimental study on the influence of different activators on the engineering properties of the CTB containing fly ash. CTB samples are mixed with different contents of calcium formate, sodium sulfate, and cement clinker (4%, 8%, and 12% by mass of total binder) and cured in a cubic chamber (at 20°C and RH 90 ± 5%) for 3, 7, and 28 days. Specimen tests were performed to assess the slump height, setting time, leaching water rate, vertical settlement, and strength development. Furthermore, the XRD analyses were conducted on the hydration products of fly ash-based CTB mixtures. The results show that activators can cause decrease in the slump height, leaching water rate, and vertical settlement of fly ash-based CTB mixtures. However, inclusion of cement clinker ranging from 8%–12% of total binder can reduce the slump height, setting time, leaching water rate, and vertical settlement to an acceptable range. Addition of calcium formate in the fly ash-based CTB caused negligible change in compressive strength. The compressive strength improved with higher content of sodium sulfate and cement clinker at the age of 28 days. XRD analyses showed considerable intensity counts of C-S-H gel, calcium hydroxide, and ettringite, resulting from the addition of sodium sulfate and cement clinker. This study also shows that an understanding of the effect of activators on the engineering properties of fly ash-based CTB is crucial for designing a cost-effective and workable CTB with reduced environmental impact.


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