Water Absorption Properties of Cement Pastes: Experimental and Modelling Inspections

Casnedi, Ludovica; Cocco, Ombretta; Meloni, Paola; Pia, Giorgio

doi:10.1155/2018/7679131

Cited by 10 publications

(4 citation statements)

References 50 publications

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“…Sorptivity was found from the slope of the curve obtained from the mass variation per area, I (mm), versus the square root of the time. The primary and secondary sorptivity were decided from the linear regression using successive points (27).…”

Section: Experimental Methodsmentioning

confidence: 99%

Investigation on effect of colloidal nano-silica on the strength and durability characteristics of red mud blended Portland cement paste through tortuosity

Athira

Shanmugapriya

2022

materconstrucc

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A novel binder system for cement-based composites depending upon the strength and durability characteristics is introduced in this study. The possibility of calcined red mud cement pastes with and without colloidal nano-silica (CNS) over Ordinary Portland Cement paste (OPC) at three W/B ratios (0.3, 0.4, 0.5) is evaluated. The optimum percentage of cement replacement by red mud (15%) was selected from compressive strength values of different cement replacements (5%, 10%, 15%, and 20%). Colloidal nano-silica (CNS) was added at 0.5%, 1%, 1.5%, and 2 % to the selected red mud cement paste. Water absorption, sorptivity, resistance to sulfate attack, and resistance to acid attack tests were conducted for optimum red mud cement paste with and without CNS. The experimental results are explained based on tortuosity with empirical formulas and mathematical models of pore network distribution. The tortuosity is directly proportional to the inter-connectivity of the pores. The mixes with 15% calcined red mud and 1.5% CNS replacement performed better strength and durability at all W/B ratios. The mix (R15NS1.5) with minimum tortuosity value results in the higher overall performance of the paste. The mixes with a 0.3 W/B ratio give high-performance cement paste compared to higher W/B ratios.

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Section: Experimental Methodsmentioning

confidence: 99%

Investigation on effect of colloidal nano-silica on the strength and durability characteristics of red mud blended Portland cement paste through tortuosity

Athira

Shanmugapriya

2022

materconstrucc

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“…Porosimetric measures were carried out for cement pastes, Figure 8 -Table 1, and cement mortars samples, Figure 9 untreated cement pastes is in the range of about 2.00÷0.007 µm, (modal pore radius equal to 0.30 µm), see Figure 8 and Table 1. The heat exposure causes a significant change in the porous microstructure ( [19], [58], [59], [60], [61], [62], [63]); at 100 ÷ 200 • C drying processes are dominant and particularly at 180 • C bound water starts to be released accompanied by a loss of mass (of about 8 %). A new class of voids of small radius (< 0.01µm gel pores) appears as a consequence.…”

Section: Mip Porosimetrymentioning

confidence: 99%

“…Different mathematical relationships have been proposed by various authors (such as [30], [31], [32], [33]) to indicate the relationships between compressive strength, Young Modulus and porosity of concrete. Thus, the analysis of porosimetry data, related to different damaged concrete, could be obtained to evaluate the thermal conductivity and other physical properties [34], [35]. This paper presents the results of an experimental investigation on reinforced concrete, cement pastes and mortars exposed to fire, aimed at identifying the benchmarks necessary to reconstruct the thermal path.…”

Section: Introductionmentioning

confidence: 99%

Thermal Path Reconstruction for Reinforced Concrete Under Fire

2019

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In post-fire investigation, the damage of fire-exposed concrete is usually related to the temperature time-history.This paper presents the results of an experimental investigation on reinforced concrete, cement pastes and mortars exposed to fire, aimed at identifying the benchmarks necessary to reconstruct the thermal path 15 dry core samples were obtained from a real fire damaged structure and compared to other reference dry cores collected in not damaged zones of the same structure. In addition, 16 irregular spalling samples were collected and investigated. In order to assess changes in mineralogical composition and microstructure modifications due to temperature, 20 cubic cement pastes samples and 20 prismatic mortars specimens were realized and exposed to temperature ranging from 200 • C up to 800 • C with a gradient of 10 • C/min and keeping the maximum temperature for 1h.Optical and Scanning Electron Microscopy, X-Ray Diffraction, Thermoanalysis and MIP porosimetry along with Helium picnometry allowed to investigate the damage degree and the mineralogical changes of the concrete and other cement based materials. Calibrated Colorimetry could determine fire temperature in the different parts of the samples due to colour changes in the mineralogical phases and in the microstructure of cement materials.

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“…Currently, no standard test exists for measuring the initial water uptake of cementitious materials, despite the known importance of the water-SCM interaction to fresh properties. Up to date studies [33][34][35][36] and standards [37,38] deal with the water uptake of hydrated (hardened) cementitious pastes, mortars and concretes only. However, as will be detailed herein, the IWU of various non-hydrated (dry) cementitious materials can differ widely and thus could serve as a useful supplement for the understanding of fresh properties.…”

Section: Introductionmentioning

confidence: 99%

A Porous Stone Technique to Measure the Initial Water Uptake by Supplementary Cementitious Materials

et al. 2021

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The decades-long use of supplementary cementitious materials (SCMs) as replacements for ordinary Portland cement (OPC) by the cement and concrete industry is undergoing a resurgence in research activities related to goals addressing circular economy activities, as well as reduction in CO2 emissions. Differences in the chemistry, mineralogy and reactivity of SCMs compared to OPC impact the fresh properties of concrete. Some SCMs exhibit greater initial water uptake and thus compete strongly with OPC for water during hydration. This study focuses on the early interaction with water as a primary factor that determines the resulting fresh properties and workability. Currently, no test (standard or otherwise) is available for quantifying initial interactions between water and cementitious materials. A quick and reliable method to measure the initial water uptake of SCMs is presented herein, which relies on their affinity to water. The method enables the calculation of water-to-binder ratios for different SCMs required to achieve the same workability as a reference OPC. The results are then well correlated to measured slump and bleed properties. We propose this simple technique to be used by researchers and industry practitioners to better predict the fresh properties of concretes, mortars, or pastes with SCMs.

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Water Absorption Properties of Cement Pastes: Experimental and Modelling Inspections

Cited by 10 publications

References 50 publications

Investigation on effect of colloidal nano-silica on the strength and durability characteristics of red mud blended Portland cement paste through tortuosity

Investigation on effect of colloidal nano-silica on the strength and durability characteristics of red mud blended Portland cement paste through tortuosity

Thermal Path Reconstruction for Reinforced Concrete Under Fire

A Porous Stone Technique to Measure the Initial Water Uptake by Supplementary Cementitious Materials

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