Properties of reactive powder concrete containing different combinations of fly ash and metakaolin

Hasan, Zaid Ali; Nasr, Mohammed Salah; Abed, Mohammed Kareem

doi:10.1016/j.matpr.2020.12.556

Cited by 23 publications

(16 citation statements)

References 22 publications

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“…This behavior may be attributed to the low water demand and the dense surface of the GGBS and FA particles, which only allow few water molecules to get adsorbed, thereby improving the workability at a fixed w:b ratio. This finding is in agreement with previous works [ 9 ].…”

Section: Resultssupporting

confidence: 94%

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Microstructure and Mechanical Property Evaluation of Dune Sand Reactive Powder Concrete Subjected to Hot Air Curing

et al. 2021

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The use of different sustainable materials in the manufacture of ultra-high-performance concrete (UHPC) is becoming increasingly common due to the unabating concerns over climate change and sustainability in the construction sector. Reactive powder concrete (RPC) is an UHPC in which traditional coarse aggregates are replaced by fine aggregates. The main purpose of this research is to produce RPC using dune sand and to study its microstructure and mechanical properties under different curing conditions of water curing and hot air curing. The effects of these factors are studied over a long-term period of 90 days. Quartz sand is completely replaced by a blend of crushed and dune sand, and cement is partially replaced by using binary blends of ground granulated blast furnace slag (GGBS) and fly ash (FA), which are used alongside silica fume (SF) to make a ternary supplementary binder system. Microstructural analysis is conducted using scanning electron microscopy (SEM), and engineering properties like compressive strength and flexural strength are studied to evaluate the performance of dune sand RPC. Overall, the results affirm that the production of UHPC is possible with the use of dune sand. The compressive strength of all mixes exceeded 120 MPa after 12 h only of hot air curing (HAC). The SEM results revealed the dense microstructure of RPC. However, goethite-like structures (corrosion products) were spotted at 90 days for all HAC specimens. Additionally, the use of FA accelerated the formation of such products as compared to GGBS. The effect of these products was insignificant from a mechanical point of view. However, additional research is required to determine their effect on the durability of RPC.

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Section: Resultssupporting

confidence: 94%

“…On the other hand, Hasan et al [ 9 ] reported a significant reduction in the mechanical strength of RPC containing supplementary cementitious materials, FA and metakaolin, under standard curing. The reduction was more pronounced when the volume of FA increased.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Property Evaluation of Dune Sand Reactive Powder Concrete Subjected to Hot Air Curing

et al. 2021

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“…Due to the filling effect contributed by the small MK particle size, the cracks that typically form in cement specimens are largely filled, which improves the density and compressive strength of the workpiece. Moreover, the high pozzolanic activity enables the large number of Al 2 O 3 and SiO 2 within MK to react with Ca(OH) 2 to generate a fibrous calcium silicate hydrate (C–S–H) gel, which further improves the compressive strength of the specimen [ 28 , 29 ]. However, if metakaolin exceeds 10% substitution, the compressive strength of the specimen instead declines substantially.…”

Section: Resultsmentioning

confidence: 99%

Investigating the Mechanical Properties and Durability of Metakaolin-Incorporated Mortar by Different Curing Methods

Dong

Pei

et al. 2022

Materials

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In this paper, the traditional, silicate-based Portland cement (PC) was employed as the control to explore the impact of adding varying amounts of metakaolin (MK) on the mechanical properties of cement mortar. In fact, as a mineral admixture, metakaolin (MK) has the ability to significantly improve the early strength and sulfate resistance of cement mortar in traditional, silicate-based Portland cement (PC). In addition to this, the performance of Portland cement mortar is greatly affected by the curing mode. The previous research mainly stays in the intermittent curing and alkaline excitation mode, and there are few studies on the influence of relatively humidity on it. Moreover, the paper investigated the impact of four different curing methods about humidity on the mechanical properties and sulfate resistance. The results show that the best content of metakaolin in Portland cement is 10% (M10), and the best curing method is 95% humidity in the first three days followed by 60% humidity in the later period (3#). Based on previous literature that suggests that adding MK thickens water film layer on the surface of mortar, the mechanism of MK increasing the early strength of cement was analyzed. The compressive strength of the Portland cement containing 10% MK (M10) after 1 day curing is 3.18 times that of pristine PC mortar, and is comparable if PC is cured for three days under the same curing conditions. The traditional PC mortar is highly dependent on the wet curing time, and normally requires a curing time of at least seven days. However, the incorporation of MK can greatly reduce the sensitivity of Portland cement to water; MK cement mortar with only three days wet curing (3#M10) can reach 49.12 MPa after 28 days, which can greatly shorten the otherwise lengthy wet curing time. Lastly, the cement specimens with MK also demonstrated excellent resistance against sulfate corrosion. The work will provide a strong theoretical basis for the early demolding of cement products in construction projects. At the same time, this study can also provide a theoretical reference for the construction of climate drought and saline land areas, which has great reference value.

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“…The percent of water absorption increased clearly at 400 ᵒC and 600 ᵒC. With increasing temperature, the mixture that having fibers (polypropylene) showed increased in water absorption and that may be because of cracks propagation due to melting fibers [4,30].…”

Section: Weight Lossmentioning

confidence: 98%

“…The use of such recyclable materials in construction is considered eco-friendly and appropriate to reduce serious problems such as nonbiodegradability, accumulation of wastes, and protect natural resources from consumption. On the other hand that would open the field forwards the researchers to explore the desirable produced characteristics and the limitations [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Sustainable Mortar Made with Local Clay Bricks and Glass Waste Exposed to Elevated Temperatures

2021

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The present study involved assessing the replacement of fine aggregate in the mortar with sustainable local materials like clay bricks and glass included 168 specimens (cubes and prisms). Seven mixtures were cast for this work, one control mix (R1) with 100% natural sand whereas mixes from R2 to R5 have 10% and 20% replacing natural sand with waste clay bricks and waste glass separately and respectively. Mix R6 was included 20% replacing sand with combination waste materials (10% waste clay bricks with 10% waste glass). Mix R7 has involved the same percent of replacing the previous mix R6 but with adding Polypropylene fibers 1% by volume. The samples have put in an electrical oven for one hour at 200, 400, and 600 ᵒC then cooled to room temperature to be tested and compared with samples at normal temperature 24 ᵒC. Different mechanical tests were adopted involved flow tests, density, weight loss, compressive strength, flexural strength, and water absorption. The results at different temperatures were discussed where many findings were specified. The flexural strength at 400 ᵒC was showed improving by 56% for 20% waste clay brick and 69% with 10% waste glass, as well all combination mixes illustrated higher strength than the control. Doi: 10.28991/cej-2021-03091729 Full Text: PDF

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Properties of reactive powder concrete containing different combinations of fly ash and metakaolin

Cited by 23 publications

References 22 publications

Microstructure and Mechanical Property Evaluation of Dune Sand Reactive Powder Concrete Subjected to Hot Air Curing

Microstructure and Mechanical Property Evaluation of Dune Sand Reactive Powder Concrete Subjected to Hot Air Curing

Investigating the Mechanical Properties and Durability of Metakaolin-Incorporated Mortar by Different Curing Methods

Sustainable Mortar Made with Local Clay Bricks and Glass Waste Exposed to Elevated Temperatures

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