Effect of W/C Ratio on Durability and Porosity in Cement Mortar with Constant Cement Amount

Kim, Seong Su; Lee, Kwang-Myung; Bang, Jae-Wook; Kwon, Seung-Jun

doi:10.1155/2014/273460

Cited by 129 publications

(70 citation statements)

References 22 publications

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“…2. With the increase of w/c ratio, the increase of porosity is a common phenomenon observed from experiments203233 and simulations34. The stiffness of the mineral phase ranges from 62 GPa to 64 GPa in all the samples, comparable to previous studies25.…”

Section: Resultssupporting

confidence: 86%

Mesoscopic packing of disk-like building blocks in calcium silicate hydrate

Zhou

Lau

2016

Sci Rep

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At 100-nanometer length scale, the mesoscopic structure of calcium silicate hydrate (C-S-H) plays a critical role in determining the macroscopic material properties, such as porosity. In order to explore the mesoscopic structure of C-S-H, we employ two effective techniques, nanoindentation test and molecular dynamics simulation. Grid nanoindentation tests find different porosity of C-S-H in cement paste specimens prepared at varied water-to-cement (w/c) ratios. The w/c-ratio-induced porosity difference can be ascribed to the aspect ratio (diameter-to-thickness ratio) of disk-like C-S-H building blocks. The molecular dynamics simulation, with a mesoscopic C-S-H model, reveals 3 typical packing patterns and relates the packing density to the aspect ratio. Illustrated with disk-like C-S-H building blocks, this study provides a description of C-S-H structures in complement to spherical-particle C-S-H models at the sub-micron scale.

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Section: Resultssupporting

confidence: 86%

Mesoscopic packing of disk-like building blocks in calcium silicate hydrate

Zhou

Lau

2016

Sci Rep

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“…Generally, the increase in the amount of water caused a decrease in strength in all types of mortars due to the increase of the water-binder ratio. The effect of increased water-binder ratio has been the subject of numerous research, for example, by Elnemr [75], Lawrence [76], and Kim et al [77]. Both compressive and flexural strength dropped by 12-35%, depending on the type of lime (Figure 13).…”

Section: Impact Of Inaccuracies In Dosing Watermentioning

confidence: 99%

Assessment of the Impact of Inaccuracy and Variability of Material and Selected Technological Factors on Physical and Mechanical Properties of Fresh Masonry Mortars and Plasters

et al. 2020

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The article presented the analysis of the impact that various kinds of technological inaccuracies have on the properties of fresh masonry mortars and plasters. Analyzed were the inaccuracies in dosing of mortar components, namely, water, lime, and air-entraining plasticizing admixture (APA) (±10% of mass), and the effect of variable technological conditions, namely, different mixing intensity (fast, slow, normal) and temperature (5 • C, 20 • C, and 35 • C) during first 72 h after mixing. The impact of differences in the properties of cement and aerial (hydrated) lime originating from different manufacturers was also analyzed. The impact of these factors was determined for consistency, density, air content, compressive, and flexural strength. The sensitivity to changes in the analyzed properties was determined by the coefficient of variation. Changes in the dosing of constituents, mixing speed, and temperature adversely affected strength properties. For mortars with APA, these changes exceeded 20% and reached 40%. The greatest impact was evident in the consistency, especially with an excess of APA, where changes ranged from 6% to 80%. The results showed greater resistance of cement-lime mortars to changing selected technological conditions and errors in measuring the amount of ingredients than mortars with air-entraining plasticizing admixture (APA). Materials 2020, 13, 1382 2 of 29 using waste materials, e.g., concrete waste [5], glass waste [6], brick flour [7], granite flour [8], marble powder [9], and others. A significant part of the research is devoted to modifying mortars with various additives to improve their properties while partially replacing fillers and binders with waste materials.For example, Harbi et al.[10] carried out the experimental work focused on the study of the possibility of using kaolin dust as filler in the sand, combined with additions of glass powder, brick waste, and metakaolin in order to improve the mechanical performance of the mortar. Mixtures containing glass powder and/or metakaolin turned out to be better than those containing brick waste. Similar research was carried out by Boukour and Benmalek [11], who analyzed the effect of two wastes: crushed clay brick and tire rubber aggregate in cement mortar reinforced by a resinous latex. Test results indicated a decrease in water absorption and shrinkage of such cement mortar.Atypical addition to mortar, which has been a subject of research, is recycled polyethylene terephthalate (PET) bottles [12]. Test results of this experiment have indicated that higher compressive and flexural strength can be obtained for thusly modified cement mortars. Other atypical additions to the mortar that have been researched are organic agents as vinegar, gram pulse, and frog contaminated water and their influence on mechanical properties and mortar's performance [13]. It has been concluded that organic materials chosen for the study adversely affect the compressive strength of cement mortars, especially after six months.Research has also been carried o...

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“…Since Ca(OH) 2 is a weak link in strengthening of concrete, sample with water-cement ratio of 0.6 is undesirable. Further, higher amount of unreacted water will also cause more amount of porosity in the structure, thereby decreasing the mechanical strength 17 . Also, as evident from fig.…”

Section: Analysis Of the Formation Of Key Hydration Productsmentioning

confidence: 99%

Hydration kinetics of cement composites with varying water-cement ratio using terahertz spectroscopy

et al. 2015

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Cement is mixed with water in an optimum ratio to form concrete with desirable mechanical strength and durability. The ability to track the consumption of major cement constituents, viz., Tri-and Dicalcium Silicates (C3S, C2S) reacting with water along with the formation of key hydration products, viz., Calcium-Silicate-Hydrate (C-S-H) which gives the overall strength to the concrete and Calcium Hydroxide (Ca(OH) 2 ), a hydration product which reduces the strength and durability, using an efficient technique is highly desirable. Optimizing the amount of water to be mixed with cement is one of the main parameters which determine the strength of concrete. In this work, THz spectroscopy has been employed to track the variation in hydration kinetics for concrete samples with different water-cement ratios, viz., 0.3, 0.4, 0.5 and 0.6. Results show that for the sample with water-cement ratio of 0.3, significant amount of the C3S and C2S remain unreacted even after the initial hydration period of 28 days while for the cement with water-cement ratio of 0.6, most of the constituents get consumed during this stage. Analysis of the formation of Ca(OH) 2 has been done which shows that the concrete sample with water-cement ratio of 0.6 produces the highest amount of Ca(OH) 2 due to higher consumption of C3S/C2S in presence of excess water which is not desirable. Samples with water-cement ratio of 0.4 and 0.5 show more controlled reaction during the hydration which can imply formation of an optimized level of desired hydration products resulting in a more mechanically strong and durable concrete.

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Effect of W/C Ratio on Durability and Porosity in Cement Mortar with Constant Cement Amount

Cited by 129 publications

References 22 publications

Mesoscopic packing of disk-like building blocks in calcium silicate hydrate

Mesoscopic packing of disk-like building blocks in calcium silicate hydrate

Assessment of the Impact of Inaccuracy and Variability of Material and Selected Technological Factors on Physical and Mechanical Properties of Fresh Masonry Mortars and Plasters

Hydration kinetics of cement composites with varying water-cement ratio using terahertz spectroscopy

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