Effect of pozzolanic wastes on mechanical properties, durability and microstructure of the cementitious mortars

Pachideh, Ghasem; Gholhaki, Majid; Ketabdari, Hesam

doi:10.1016/j.jobe.2020.101178

Cited by 30 publications

(15 citation statements)

References 19 publications

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“…The evaporation of a portion of water results in the weight loss of the specimens after removing from the furnace 35 . At 100°C, the water starts boiling and evaporating.…”

Section: Resultsmentioning

confidence: 99%

“…The evaporation of a portion of water results in the weight loss of the specimens after removing from the furnace. 35 At 100 C, the water starts boiling and evaporating. Figure 7 illustrates the trend of weight loss under different temperatures compared to 25 C. As shown, there is a direct relationship between the compressive strength and the weight loss of the specimens.…”

Section: Compressive Strengthmentioning

confidence: 99%

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Cementitious mortars containing pozzolana under elevated temperatures

Toufigh

Pachideh

2022

Structural Concrete

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In recent years, pozzolana are being increasingly used in different types of concretes and mortars. This investigation aims to evaluate the effect of replacing 7, 14, 21, and 28% cement (by weight) with silica fume (SF), granulated blast furnace slag (GBFS), zeolite, and fly ash (FA) under elevated temperatures. Forty mix designs were built with various water‐to‐cement ratios and plasticizers. Three hundred and six specimens were prepared, and the flexural, uniaxial compression and tensile tests were performed on specimens after exposure to elevated temperatures between 25°C and 900°C. The X‐ray diffraction (XRD) test was then performed on the two series of specimens. Accordingly, the results reveal that the average compressive strength of the control specimen and those containing SF, GBFS, Zeolite, and FA, respectively, is 23.17, 32.2, 34.87, 29.67, and 17.38 MPa. These values for the tensile and flexural strength tests are 0.77, 1.1, 1.02, 0.98, and 0.61 and 0.77, 1.23, 1.29, 0.93, and 0.87 MPa, respectively. Therefore, specimens containing zeolite and GBFS had better performance against heat. As per the increase in temperature, the size of the grains in the specimens containing the SF and GBFS in the XRD test shrunk less (about 6%) in contrast to those of the control specimen. The artificial neural networks (ANNs) were used to estimate the mechanical properties of the specimens at the age of 28 days.

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“…The evaporation of a portion of water results in the weight loss of the specimens after removing from the furnace 35 . At 100°C, the water starts boiling and evaporating.…”

Section: Resultsmentioning

confidence: 99%

Section: Compressive Strengthmentioning

confidence: 99%

Cementitious mortars containing pozzolana under elevated temperatures

Toufigh

Pachideh

2022

Structural Concrete

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“…The hydration reaction between fine aggregates and cementitious materials was inhibited by the high content of residual carbon in the CGCS, which hindered the growth and connection of hydration products and weakened the mechanical properties of mixtures. With the increase in CGCS replacement, the agglomeration phenomenon of FA became increasingly obvious ( Figure 9 ), thereby affecting the secondary hydration and the strength of concrete [ 50 , 51 ].…”

Section: Resultsmentioning

confidence: 99%

Mechanical Properties of Ultra-High Performance Concrete with Coal Gasification Coarse Slag as River Sand Replacement

Zhu¹,

Lian

Zhai

et al. 2022

Materials

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Coal gasification coarse slag (CGCS) is a by-product of coal gasification. Despite its abundance, CGCS is mostly used in boiler blending, stacking, and landfill. Large-scale industrial applications of CGCS can be environment-friendly and cost saving. In this study, the application of CGCS as a substitute for river sand (RS) with different replacement ratios in ultra-high performance concrete (UHPC) was investigated. The effects of CGCS replacement ratios on the fluidity and mechanical properties of specimens were examined, and the effect mechanisms were explored on the basis of hydration products and the multi-scale (millimetre-scale and micrometre-scale) microstructure analysis obtained through X-ray diffraction (XRD), scanning electron microscopy, and X-ray energy-dispersive spectroscopy. With an increase in the CGCS replacement ratio, the water–binder ratio (w/b), flexural strength, and compressive strength decreased. Specimens containing CGCS of ≤25% can satisfy the strength requirement of non-structural UHPC, with flexure strength of 29 MPa and compressive strength of 111 MPa at day 28. According to the XRD results and multi-scale microstructure analysis, amorphous glass beads in CGCS positively influenced ettringite generation due to the pozzolanic activity. Porous carbon particles in CGCS showed strong interfacial bonding with cement slurry due to internal hydration; this bonding was conducive to improving the mechanical strength. However, CGCS hindered hydration in the later curing stage, leading to an increase in the unreacted cement and agglomeration of fly ash; in addition, at a CGCS replacement ratio of up to 50%, an apparent interfacial transition zone structure was observed, which was the main contributor to mechanical strength deterioration.

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“…The prepared beam samples were tested after 28 days of standard curing and the results of flexural strength tests for the control concretes and the PET bottle concretes are summarized below in Table 23. The flexural strength of the prism specimen is calculated using the following formula according to [18].…”

Section: Flexural Strength Testsmentioning

confidence: 99%

Polyethylene Terephthalate Wastes as a Partial Replacement for Fine Aggregates in Concrete Mix, Case of Jimma Town, South West Ethiopia

Amibo

Bayu

Akuma

2021

SJE

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In this research design of the concrete mix were performed according to the design expert method. The total mixes of 6 and total of 72 samples to consist of concrete grade C-25. The test samples were prepared with the of substitution percentage for the fine aggregate by 1, 2, 3, 4, and 5% of PET plastic waste aggregate. Moreover, a control mix without replacement for the fine aggregate was used to have a relative analysis. The produced samples consist of concrete cubes, cylinders, and beams. Furthermore, laboratory experiments were carried out for the produced concrete test samples. The experiments conducted were; material property test, slump test, unit weight test, compressive strength test, splitting tensile strength test, and flexural strength test. The test results were investigated and compared with the corresponding conventional concrete characteristics and reflect that there was a slight increase in compressive strength of the concrete up to 3% replacement and reduction in compressive strength increases beyond 3% replacement due to the replacement of PET aggregates, also like compressive strength there was an increase of tensile strength obtained with increasing PET bottle aggregate content up to 3% replacement. But more than 3% substitution of fine aggregate with PET bottle fiber, results in a reduced in tensile strength, and flexural strength. This test result shows that possible to use PET bottles in concrete production as a partial substitution for fine aggregates not more than 3% replacement.

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Effect of pozzolanic wastes on mechanical properties, durability and microstructure of the cementitious mortars

Cited by 30 publications

References 19 publications

Cementitious mortars containing pozzolana under elevated temperatures

Cementitious mortars containing pozzolana under elevated temperatures

Mechanical Properties of Ultra-High Performance Concrete with Coal Gasification Coarse Slag as River Sand Replacement

Polyethylene Terephthalate Wastes as a Partial Replacement for Fine Aggregates in Concrete Mix, Case of Jimma Town, South West Ethiopia

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