Performance of crystalline forming additive materials in concrete

Elsalamawy, Mona; Mohamed, Ashraf Ragab; Abosen, Abdellatif Elsayed

doi:10.1016/j.conbuildmat.2019.117056

Cited by 25 publications

(25 citation statements)

References 19 publications

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“…This finding is also in agreement with Elsalamawy et al's study [23], which examines the available space in the matrix of mortars with CWA. In this study, a reduction of 65 ± 5% in available space width was observed for CWA treated samples [23]. Another study by Zizkova et al [18] also concluded that a higher CWA content (i.e., 1.5% cement mass) can result in a reduction in porosity exposed to aggressive environments.…”

Section: Phase Isupporting

confidence: 92%

“…The morphologies of the specimens containing CWA materials showed that the formed crystals contributed significantly to reduce the total porosity, which confirmed the high performance of concrete containing CWA materials in practice. For the formed crystals, the other phase of C-S-H gel reduced the water transport of hardened concrete by partially blocking the pore structure [23,26,49]. This finding is also in agreement with Elsalamawy et al's study [23], which examines the available space in the matrix of mortars with CWA.…”

Section: Phase Isupporting

confidence: 88%

“…For the formed crystals, the other phase of C-S-H gel reduced the water transport of hardened concrete by partially blocking the pore structure [23,26,49]. This finding is also in agreement with Elsalamawy et al's study [23], which examines the available space in the matrix of mortars with CWA. In this study, a reduction of 65 ± 5% in available space width was observed for CWA treated samples [23].…”

Section: Phase Isupporting

confidence: 88%

“…L and O-K mixtures show mostly CSH gel as their hydration product while intermix of mono-carbonate and CSH phases were observed for O and L-K mixtures which indicates some of fine limestone reacted with the cement pore fluid to form mono-carbonate. A considerable reduction in calcium hydroxide content "CH" was documented in concrete mixture containing CWA materials [23]; this may be due to the presence of highly fineness silica that can react with CH. Presence of CWA in the mix did not indicate any differences in major hydration products than those in control samples.…”

Section: Phase IImentioning

confidence: 99%

“…Hence, the combination of SAP and CWA was recommended for macro-crack sealing. Elsalamawy et al's [23] study indicated that different phases of calcium silicate hydrate C-S-H have been formed in presence of CWA materials. These phases range from round particles to needle-like crystals with Ca/Si ratio ranging from 2.4 to 3.2.…”

Section: Introductionmentioning

confidence: 99%

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Inventive Microstructural and Durability Investigation of Cementitious Composites Involving Crystalline Waterproofing Admixtures and Portland Limestone Cement

2020

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The durability of a cement-based material is mainly dependent on its permeability. Modifications of porosity, pore-structure and pore-connectivity could have significant impacts on permeability improvement, which eventually leads to more durable materials. One of the most efficient solutions in this regard is to use permeability reducing admixtures (PRA). Among these admixtures for those structures exposed to hydro-static pressure, crystalline waterproofing admixtures (CWA) have been serving in the construction industries for decades and according to ACI 212—chemical admixtures’ report, it has proven its capability in permeability reduction and durability-enhancement. However, there is substantial research being done on its durability properties at the macro level but very limited information available regarding its microstructural features and chemical characteristics at the micro level. Hence, this paper presents one of the first reported attempts to characterize microstructural and chemical elements of hydration products for cementitious composites with CWA called K, P and X using Scanning Electron Microscopy (SEM). Backscattered SEM images taken from a polished-section of one CWA type—K—admixture were analyzed in ImageJ to obtain paste matrix porosity, indicating a lower value for the CWA-K mixture. X-ray analysis and SEM micrographs of polished sections were examined to identify chemical compositions based on atomic ratio plots and brightness differences in backscatter-SEM images. To detect chemical elements and the nature of formed crystals, the fractured surfaces of three different CWA mixtures were examined. Cementitious composites with K admixture indicated needle-like crystal formation—though different from ettringite; X and P admixtures showed sulfur peaks in Energy Dispersive Spectrum (EDS) spectra, like ettringite. SEM images and X-ray analyses of mixtures incorporating Portland Limestone Cement (PLC) indicated lower-than-average porosity but showed different Si/Ca and Al/Ca atomic ratios.

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Section: Phase Isupporting

confidence: 92%

Section: Phase Isupporting

confidence: 88%

Section: Phase Isupporting

confidence: 88%

Section: Phase IImentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Inventive Microstructural and Durability Investigation of Cementitious Composites Involving Crystalline Waterproofing Admixtures and Portland Limestone Cement

2020

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Experimental investigations on mechanical performance, synergy assessment, and microstructure of pozzolanic and non‐pozzolanic hybrid steel fiber reinforced concrete

Boomibalan,

Isleem,

Swaminathan

et al. 2024

Structural Concrete

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This paper investigates the effects of pozzolanic substitutions for ordinary Portland cement (OPC) with silica fume (SF) and metakaolin (MK) on the mechanical and toughness performances of steel fiber reinforced concrete (SFRC). Initially, a reference concrete mix with a water‐to‐binder ratio of 0.4 is blended with different volume fractions of steel fibers with varying geometry: crimped steel (CS) and straight steel (SS), both individually and in combination, to examine their mechanical properties. In the subsequent phase, the study investigates the impact of combining macro‐ and microsteel fibers on flexural toughness, to determine potential synergy for suitable combinations. Also, the possible influence of pozzolans in the variation of flexural toughness of hybrid steel fiber reinforced concrete (Hy‐SFRC) was evaluated. Hybridization of steel fibers was found effective in improving the workability of the concrete mix up to 11%. SFRC mixes containing pozzolans exhibited a significant enhancement in compressive strength, modulus of rupture, and modulus of elasticity compared to non‐pozzolanic SFRC. The hybrid combination of CS 1.5% and SS 0.5% was considered the best in terms of mechanical properties. Additionally, the results of synergy assessment showed that hybridization of steel fibers in the pozzolanic concrete mix was particularly effective in the post‐cracking stages with a positive 14% compared to a negative 8% in the pre‐cracking stage. The pozzolanic addition improved the flexural toughness of Hy‐SFRC to about 10%–20%. Blending of SF and MK in Hy‐SFRC was found effective in enhancing the toughness mechanism of concrete compared to Hy‐SFRC mixes containing binary SF and MK, indicating a stronger bond between the fibers and the matrix resulting from the pore refinement and hydration products developed at the interface. Hy‐SFRC containing a ternary pozzolanic mix of SF 10% and MK 10% gave the best results in flexural toughness, and the corresponding synergy values were found to be the maximum. The results were consistent with the morphology analysis, which revealed an increase in hydration products at the interface between the aggregate and concrete matrix, as well as between the steel fiber and concrete matrix, due to the ternary blending of SF and MK.

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The Effect of Crystalline Waterproofing Materials on Accelerated Corrosion of Steel Reinforcement in Concrete

2021

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Performance of crystalline forming additive materials in concrete

Cited by 25 publications

References 19 publications

Inventive Microstructural and Durability Investigation of Cementitious Composites Involving Crystalline Waterproofing Admixtures and Portland Limestone Cement

Inventive Microstructural and Durability Investigation of Cementitious Composites Involving Crystalline Waterproofing Admixtures and Portland Limestone Cement

Experimental investigations on mechanical performance, synergy assessment, and microstructure of pozzolanic and non‐pozzolanic hybrid steel fiber reinforced concrete

The Effect of Crystalline Waterproofing Materials on Accelerated Corrosion of Steel Reinforcement in Concrete

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