Effect of Strain History and Mixture Proportions on Early-Age Cement Paste and Mortar Stress Relaxation

: The early-age carbonation curing technique is an effective way to improve the performance of cement-based materials and reduce their carbon footprint. This work investigates the early mechanical properties and microstructure of calcium sulfoaluminate (CSA) cement specimens under early-age carbonation curing, considering five factors: briquetting pressure, water–binder (w/b) ratio, starting point of carbonation curing, carbonation curing time, and carbonation curing pressure. The carbonization process and performance enhancement mechanism of CSA cement are analyzed by mercury intrusion porosimetry (MIP), thermogravimetry and derivative thermogravimetry (TG-DTG) analysis, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that early-age carbonation curing can accelerate the hardening speed of CSA cement paste, reduce the cumulative porosity of the cement paste, refine the pore diameter distribution, and make the pore diameter distribution more uniform, thus greatly improving the early compressive strength of the paste. The most favorable w/b ratio for the carbonization reaction of CSA cement paste is between 0.15 and 0.2; the most suitable carbonation curing starting time point is 4 h after initial hydration; the carbonation curing pressure should be between 3 and 4 bar; and the most appropriate time for carbonation curing is between 6 and 12 h.

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Controlling the early-age hydration heat release of cement paste for deep-water oil well cementing: A new composite designing approach

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.122949 ◽

2021 ◽

Vol 285 ◽

pp. 122949

Author(s):

Da-heng Wang ◽

Xiao Yao ◽

Tao Yang ◽

Wen-rui Xiang ◽

Ying-tao Feng ◽

...

Keyword(s):

Heat Release ◽

Cement Paste ◽

Deep Water ◽

Hydration Heat ◽

Early Age ◽

Oil Well ◽

Early Age Hydration

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Drying effect on cement paste porosity at early age observed by NMR methods

Construction and Building Materials ◽

10.1016/j.conbuildmat.2011.07.012 ◽

2012 ◽

Vol 29 ◽

pp. 496-503 ◽

Cited By ~ 32

Author(s):

Paméla F. Faure ◽

Sabine Caré ◽

Julie Magat ◽

Thierry Chaussadent

Keyword(s):

Cement Paste ◽

Early Age ◽

Nmr Methods

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Hydration and microstructural characterization of early-age cement paste with ultrasonic wave velocity and electrical resistivity measurements

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.124508 ◽

2021 ◽

Vol 303 ◽

pp. 124508

Author(s):

Hong Jae Yim ◽

Young Hwan Bae ◽

Yubin Jun

Keyword(s):

Electrical Resistivity ◽

Ultrasonic Wave ◽

Wave Velocity ◽

Cement Paste ◽

Microstructural Characterization ◽

Early Age ◽

Ultrasonic Wave Velocity ◽

Resistivity Measurements

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QUASI-LINEAR VISCOELASTIC MODELLING OF UNCURED PREPREGS UNDER COMPACTION

10.12783/asc36/35952 ◽

2021 ◽

Author(s):

SIDDHESH S. KULKARNI ◽

KAMRAN A. KHAN ◽

REHAN UMER

Keyword(s):

Stress Relaxation ◽

Relaxation Function ◽

Soft Tissues ◽

Volume Fraction ◽

Time Dependent ◽

Strain History ◽

Manufacturing Processes ◽

Fiber Volume ◽

Consolidation Process ◽

Thermoset Resin

Reinforcement compaction sometimes referred as consolidation process and is one of the key steps in various composite manufacturing processes such as autoclave and out-of-autoclave processing. The prepregs consist of semi-cured thermoset resin system impregnating the fibers. hence, the prepreg shows strong viscoelastic compaction response, which strongly depends on compaction speed and stress relaxation. modeling of time-dependent response is of utmost importance to understand the behavior of prepregs during different stages of composites manufacturing processes. The quasilinear viscoelastic (QLV) theory has been extensively used for the modeling of viscoelastic response of soft tissues in biomedical applications. In QLV approach, the stress relaxation can be expressed in terms of the nonlinear elastic function and the reduced relaxation function. The constitutive equation can be represented by a convolution integral of the nonlinear strain history, and reduced relaxation function. This study adopted a quasilinear viscoelastic modeling approach to describe the time dependent behavior of uncured-prepregs under compression. The model was modified to account for the compaction behavior of the prepreg under a compressive load. The deformation behavior of the prepreg is usually characterized by the fiber volume fraction, V . In this study, the material used was a 2/2 Twill weave glass prepreg (M26T) supplied by Hexcel® Industries USA. We performed a compaction experiment of the uncured prepreg at room temperature at different displacement rate and subsequent relaxation to describe the viscoelastic behavior of the prepreg. The model parameter calibration was performed using the trust-region-reflective algorithm in matlab to a selected number of test data. The calibrated model was then used to predict the rate dependent compaction and relaxation response of prepregs for different fiber volume fractions and strain rates.

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Basic creep of cement paste at early age - the role of cement hydration

Cement and Concrete Research ◽

10.1016/j.cemconres.2018.11.013 ◽

2019 ◽

Vol 116 ◽

pp. 191-201 ◽

Cited By ~ 14

Author(s):

Mateusz Wyrzykowski ◽

Karen Scrivener ◽

Pietro Lura

Keyword(s):

Cement Paste ◽

Cement Hydration ◽

Basic Creep ◽

Early Age

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Effect of Fly Ash on the early Age Cracking Performance of Cement Paste

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.584-586.894 ◽

2014 ◽

Vol 584-586 ◽

pp. 894-898

Author(s):

Ping Zhang ◽

Guan Guo Liu ◽

Chao Ming Pang ◽

Bing Du ◽

Hong Gen Qin

Keyword(s):

Computed Tomography ◽

Fly Ash ◽

Cement Paste ◽

Test Method ◽

Early Age ◽

Cement Ratio ◽

X Ray ◽

Cracking Performance ◽

X Ray Computed ◽

Ct Test

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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A Simplified Method for Elastic-Plastic-Creep Structural Analysis

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3239688 ◽

1985 ◽

Vol 107 (1) ◽

pp. 231-237 ◽

Cited By ~ 1

Author(s):

A. Kaufman

Keyword(s):

Finite Element ◽

Stress Relaxation ◽

Kinematic Hardening ◽

Nonlinear Finite Element ◽

Strain History ◽

Stress Strain ◽

Element Analysis ◽

Inelastic Analysis ◽

Simplified Method ◽

Time Required

A simplified inelastic analysis computer program (ANSYMP) was developed for predicting the stress-strain history at the critical location of a thermomechanically cycled structure from an elastic solution. The program uses an iterative and incremental procedure to estimate the plastic strains from the material stress-strain properties and a plasticity hardening model. Creep effects can be calculated on the basis of stress relaxation at constant strain, creep at constant stress or a combination of stress relaxation and creep accumulation. The simplified method was exercised on a number of problems involving uniaxial and multiaxial loading, isothermal and nonisothermal conditions, dwell times at various points in the cycles, different materials, and kinematic hardening. Good agreement was found between these analytical results and nonlinear finite element solutions for these problems. The simplified analysis program used less than 1 percent of the CPU time required for a nonlinear finite element analysis.

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