Computational investigation of pore permeability and connectivity from transmission X-ray microscope images of a cement paste specimen

The X ray computed tomography (X-CT) was applied to test the cracking resistance of cement paste, and the hydration process was monitored to study the effect of fly ash on the early age cracking performance. The results showed that the hydration heat reduced with the increase of fly ash under the same water-cement ratio. Within 24h, the porosity increased with time. The addition of fly ash increased the proportion of large holes and then changed the internal stress state. Using X-CT test method and by comparing the number of cracks, the sample with 20% FA was found to have the most serious cracks, whereas the sample with 30% FA had the best crack resistance.

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The Specific Surface of Hardened Portland Cement Paste as Measured by Low-Angle X-Ray Scattering

10.5703/1288284313854 ◽

1973 ◽

Cited By ~ 1

Author(s):

Douglas Windslow

Keyword(s):

Portland Cement ◽

Specific Surface ◽

Cement Paste ◽

X Ray ◽

X Ray Scattering ◽

Portland Cement Paste ◽

Ray Scattering

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Effect of Waste Clay Brick Powder on Physical and Mechanical Properties of Cement Paste

The Open Civil Engineering Journal ◽

10.2174/1874149502115010370 ◽

2021 ◽

Vol 15 (1) ◽

pp. 370-380

Author(s):

David Sinkhonde ◽

Richard Ocharo Onchiri ◽

Walter Odhiambo Oyawa ◽

John Nyiro Mwero

Keyword(s):

Compressive Strength ◽

Cement Paste ◽

Setting Time ◽

Partial Replacement ◽

Clay Brick ◽

X Ray ◽

Cement Replacement ◽

Clay Bricks ◽

Brick Powder ◽

Scanning Electron

Background: Investigations on the use of waste clay brick powder in concrete have been extensively conducted, but the analysis of waste clay brick powder effects on cement paste is limited. Materials and Methods: This paper discusses the effects of waste clay brick powder on cement paste. Fragmented clay bricks were grounded in the laboratory using a ball mill and incorporated into cementitious mixes as partial replacement of Ordinary Portland Cement. Workability, consistency, setting time, density and compressive strength properties of paste mixes were investigated to better understand the impact of waste clay brick powder on the cementitious paste. Four cement replacement levels of 2.5%, 5%, 7.5% and 10% were evaluated in comparison with the control paste. The chemical and mineral compositions were evaluated using X-Ray Fluorescence and X-Ray Diffractometer, respectively. The morphology of cement and waste clay brick powder was examined using a scanning electron microscope. Results: The investigation of workability exhibited a reduction of slump attributed to the significant addition of waste clay brick powder into the cementitious mixes, and it was concluded that waste clay brick powder did not significantly influence the density of the mixes. In comparison with the control paste, increased values of consistency and setting time of cement paste containing waste clay brick powder confirmed the information available in the literature. Conclusion: Although waste clay brick powder decreased the compressive strength of cement paste, 5% partial cement replacement with waste clay brick powder was established as an optimum percentage for specimens containing waste clay brick powder following curing periods of 7 and 28 days. Findings of chemical composition, mineral composition and scanning electron microscopy of waste clay brick powder demonstrated that when finely ground, fragmented clay bricks can be used in concrete as a pozzolanic material.

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Micromechanical modelling of deformation and fracture of hydrating cement paste using X-ray computed tomography characterisation

Composites Part B Engineering ◽

10.1016/j.compositesb.2015.11.007 ◽

2016 ◽

Vol 88 ◽

pp. 64-72 ◽

Cited By ~ 46

Author(s):

Mingzhong Zhang ◽

Andrey P. Jivkov

Keyword(s):

Computed Tomography ◽

Cement Paste ◽

Micromechanical Modelling ◽

X Ray ◽

Deformation And Fracture ◽

X Ray Computed

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X-Ray Microtomography of an Astm C109 Mortar Exposed to Sulfate Attack

MRS Proceedings ◽

10.1557/proc-370-77 ◽

1994 ◽

Vol 370 ◽

Cited By ~ 14

Author(s):

D.P. Bentz ◽

Nicos. S. Martys ◽

P. Stutzman ◽

M. S. Levenson ◽

E.J. Garboczi ◽

...

Keyword(s):

Cement Paste ◽

Sodium Sulfate ◽

Three Dimensional ◽

Sulfate Solution ◽

Sulfate Attack ◽

Sodium Sulfate Solution ◽

Mortar Sample ◽

Air Voids ◽

X Ray ◽

Dimensional Image

AbstractX-ray microtomography can be used to generate three-dimensional 5123 images of random materials at a resolution of a few micrometers per voxel. This technique has been used to obtain an image of an ASTM C109 mortar sample that had been exposed to a sodium sulfate solution. The three-dimensional image clearly shows sand grains, cement paste, air voids, cracks, and needle-like crystals growing in the air voids. Volume fractions of sand and cement paste determined from the image agree well with the known quantities. Implications for the study of microstructure and proposed uses of X-ray microtomography on cement-based composites are discussed.

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Sustainable Nanopozzolan Modified Cement: Characterizations and Morphology of Calcium Silicate Hydrate during Hydration

Journal of Nanomaterials ◽

10.1155/2015/713258 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

N. Mohamed Sutan ◽

I. Yakub ◽

M. S. Jaafar ◽

K. A. Matori ◽

S. K. Sahari

Keyword(s):

Cement Paste ◽

Physical And Mechanical Properties ◽

X Ray Diffraction ◽

X Ray ◽

Pozzolanic Reactivity ◽

Synthetic Materials ◽

Water To Cement Ratio ◽

Mechanical Properties Characterization ◽

Micro Silica ◽

By Products

There are environmental and sustainable benefits of partially replacing cement with industrial by-products or synthetic materials in cement based products. Since microstructural behaviours of cement based products are the crucial parameters that govern their sustainability and durability, this study investigates the microstructural comparison between two different types of cement replacements as nanopozzolan modified cement (NPMC) in cement based product by focusing on the evidence of pozzolanic reactivity in corroboration with physical and mechanical properties. Characterization and morphology techniques using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were carried out to assess the pozzolanic reactivity of cement paste modified with the combination of nano- and micro silica as NPMC in comparison to unmodified cement paste (UCP) of 0.5 water to cement ratio (w/c). Results were then substantiated with compressive strength (CS) results as mechanical property. Results of this study showed clear evidence of pozzolanicity for all samples with varying reactivity with NPMC being the most reactive.

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