Early Age Hydration Characteristics of Calcium Sulphoaluminate Cement Mortar Cured at a Temperature Range from −10 to 20°C

With the increasing number of infrastructures constructed in marine and cold regions, research on and applications of calcium sulphoaluminate (CSA) cement have been flourished, but the hydration process of CSA at low temperature has not been systematically investigated. To characterize the influence of low temperature on the hydration characteristics, freshly mixed CSA mortars were cured at −10, −5, 0, 5, and 20°C, respectively. The hydration process was investigated by electrical resistivity, compressive strength, and microstructure analyses. Results show that the hydration process (especially the induction period) is lengthened by low curing temperature. Both the electrical resistivity and compressive strength increase with an increase in the curing temperature. The compressive strength was reduced at a low curing temperature. Among these five curing temperatures, 5°C is the optimal curing temperature. Low temperatures do not change the kinds of hydrates, but reduce their amount. The scanning electron microscopy results illustrate that fewer hydrates fill the pores in specimens cured at low temperatures, while more hydrates form at higher temperatures. Moreover, low curing temperature contributes to the formation of coarse ettringite crystals. For the cement used at low temperature, the induction period should be reduced by adjusting the calcining process and composition proportion.

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Compressive Strength Gain Behavior and Prediction of Cement-Stabilized Macadam at Low Temperature Curing

Journal of Advanced Transportation ◽

10.1155/2020/2469436 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Yongli Xu ◽

Guang Yang ◽

Hongyuan Zhao

Keyword(s):

Compressive Strength ◽

Low Temperature ◽

Curing Temperature ◽

Strength Development ◽

Construction Process ◽

Strength Gain ◽

Estimation Model ◽

Maturity Method ◽

Temperature Ranges ◽

Natural Temperature

For cement-based materials, the curing temperature determines the strength gain rate and the value of compressive strength. In this paper, the 5% cement-stabilized macadam mixture is used. Three indoor controlled temperature curing and one outdoor natural curing scenarios are designed and implemented to study the strength development scenario law of compressive strength, and they are standard temperature curing (20°C), constant low temperature curing (10°C), day interaction temperature curing (varying from 6°C to 16°C), and one outdoor natural temperature curing (in which the air temperature ranges from 4°C to 20°C). Finally, based on the maturity method, the maturity-strength estimation model is obtained by using and analyzing the data collected from the indoor tests. The model is proved with high accuracy based on the validated results obtained from the data of outdoor tests. This research provides technical support for the construction of cement-stabilized macadam in regions with low temperature, which is beneficial in the construction process and quality control.

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Effects of Nano-CaCO3 on the Compressive Strength and Microstructure of High Strength Concrete in Different Curing Temperature

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.126 ◽

2011 ◽

Vol 121-126 ◽

pp. 126-131 ◽

Cited By ~ 3

Author(s):

Qing Lei Xu ◽

Tao Meng ◽

Miao Zhou Huang

Keyword(s):

Compressive Strength ◽

Low Temperature ◽

High Strength Concrete ◽

High Strength ◽

Curing Temperature ◽

Test Results ◽

Strength Concrete ◽

Calcium Nitrite ◽

Orientation Index ◽

Early Strength

In this paper, effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21±1°C) and low curing temperature(6.5±1°C) was studied. In order to improve the early strength of the concrete in low temperature, the early strength agent calcium nitrite was added into. Test results indicated that 0.5% dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent, but 1% and 2% dosage of nano-CaCO3 could improve the strength of the concrete by 13% and 18% in standard curing temperature and by 17% and 14% in low curing temperature at the age of 3days. According to the XRD spectrum, with the dosage up to 1% to 2%, nano-CaCO3 can change the orientation index significantly, leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.

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On the electrical resistivity of electrolytic bismuth at low temperature, and in magnetic fields

Proceedings of the Royal Society of London ◽

10.1098/rspl.1896.0065 ◽

1897 ◽

Vol 60 (359-367) ◽

pp. 425-432 ◽

Cited By ~ 2

Keyword(s):

Electrical Resistivity ◽

Low Temperature ◽

Magnetic Fields ◽

Electrical Resistance ◽

Low Temperatures ◽

Royal Society ◽

Pole Piece ◽

Interpolar Distance ◽

Pure Bismuth ◽

Transverse Magnetisation

In a previous communication to the Royal Society we have pointed out the behaviour of electrolytically prepared bismuth when cooled to very low temperatures, and at the same time subjected to transverse magnetisation. During the last summer we have extended these observations, and completed them, as far as possible, by making measurements of the electrical resistance of a wire of pure bismuth, placed transversely to the direction of the field of an electromagnet, and at the same time subjected to the low temperature obtained by the use of liquid air. Sir David Salomons was so kind as to lend us for some time his large electromagnet, which, in addition to giving a powerful field, is provided with the means of easily altering the interpolar distance of the pole pieces, and also for changing from one form of pole piece to another.

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Influence of Water-Cement Ratio and Type of Mixing Water on the Early Hydration Performance of Calcium Sulphoaluminate (CSA) Cement

Advances in Materials Science and Engineering ◽

10.1155/2021/5557763 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Chuanlin Wang ◽

Meimei Song

Keyword(s):

Compressive Strength ◽

Physical Properties ◽

Setting Time ◽

Hydration Process ◽

Chemical Shrinkage ◽

Cement Ratio ◽

Water Cement Ratio ◽

Influence Of Water ◽

Calcium Sulphoaluminate ◽

Mixing Water

The present work studies the influence of water-cement ratio and types of mixing water on the hydration process and microstructure of calcium sulphoaluminate (CSA) cement. Experimental tests on the setting time, physical properties, compressive strength, chemical shrinkage, X-ray diffraction (XRD), and scanning electron microscopy (SEM) of CSA cement paste were carried out. The XRD analysis confirmed that the main hydration product is ettringite in both freshwater and seawater mixed CSA cement with different w/c ratios. The SEM analysis and physical properties test show that both low w/c ratio and seawater can improve the microstructure of CSA cement. The test results also find out that the high w/c ratio can accelerate the hydration process, extend the setting time, lower the compressive strength, and increase the chemical shrinkage of CSA cement, and the seawater presents a similar influence except for the mechanical property. The seawater increases the compressive strength of CSA cement in the early stage of hydration but will increase the microcracks at the later hydration stage of CSA cement and reduce its mechanical properties.

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Study of Calcium Acrylate on Compressive Strength and Hydration Process of Cement

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.816-817.161 ◽

2013 ◽

Vol 816-817 ◽

pp. 161-165

Author(s):

Fu Lan Wang ◽

Qi Wang ◽

Peng Song ◽

Zhong Xi Yang ◽

Lei Tian

Keyword(s):

Hydrogen Peroxide ◽

Compressive Strength ◽

Induction Period ◽

Setting Time ◽

Comprehensive Analysis ◽

Hydration Process ◽

Cross Linking ◽

Initial Setting Time ◽

Initial Setting ◽

Speed Up

In this paper, the hydration process and strength of calcium acrylate (CA) modified cement under the effects of different additives, such as, initiator-hydrogen peroxide, accelerator-triethanolamine, and cross-linking agent-butyl acrylate, were studied. Through comprehensive analysis, the optimal content of additives of initiator, cross-linking agent, and accelerator is ascertained 3%, 10% and 3%, respectively. On the condition of optimal content of additives and CA, it can be obtained that CA can increase the exothermic rate of cement within one hour and accelerate the exothermic rate in the induction period, shorten the time of the induction period, and speed up the initial setting time of cement. Besides, CA can inhibit the transformation of AFm from AFt, improve the dispersion of cement paste, make later hydration more fully, and promote later strength.

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Low-Temperature Compressive Strength of Glass-Fiber-Reinforced Polymer Composites

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.2920146 ◽

1994 ◽

Vol 116 (3) ◽

pp. 167-172 ◽

Cited By ~ 24

Author(s):

P. K. Dutta

Keyword(s):

Compressive Strength ◽

Low Temperature ◽

Glass Fiber ◽

Low Temperatures ◽

High Strength ◽

Fiber Reinforced Polymer ◽

Fiber Reinforced ◽

Glass Fiber Reinforced Polymer ◽

Reinforced Polymer ◽

Glass Fiber Reinforced

Polymeric composites are relatively inexpensive materials of high strength, in which deformation of the matrix is used to transfer stress by means of shear traction at the fiber-matrix interface to the embedded high-strength fibers. At low temperatures, complex stresses are set up within the microstructure of the material as a result of matrix stiffening and mismatch of thermal expansion coefficients of the constituents of the composites. These stresses in turn affect the strength and deformation characteristics of the composites. This is demonstrated by compression testing of an unidirectional glass-fiber-reinforced polymer composite at room and low temperatures. The increase of compressive strength matched the analytical prediction of strength increase modeled from the consideration of increase in matrix stiffness and thermal residual stresses at low temperatures. Additional compression tests performed on a batch of low-temperature thermally cycled specimens confirmed the predictable reduction of brittleness due to suspected increase of microcrack density. The mode of failure characterized by definite pre-fracture yielding conforms more to Budiansky’s plastic microbuckling theory than to Rosen’s theory of elastic shear or extensional buckling.

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Influence of Silica Modulus and Curing Temperature on the Strength of Alkali-Activated Volcanic Ash and Limestone Powder Mortar

Materials ◽

10.3390/ma14185204 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5204

Author(s):

Adeshina Adewale Adewumi ◽

Mohd Azreen Mohd Ariffin ◽

Mohammed Maslehuddin ◽

Moruf Olalekan Yusuf ◽

Mohammad Ismail ◽

...

Keyword(s):

Compressive Strength ◽

Low Temperatures ◽

Room Temperature ◽

Volcanic Ash ◽

Curing Temperature ◽

Limestone Powder ◽

Strength Development ◽

Mass Ratio ◽

Ambient Room Temperature ◽

Alkali Activated

This present study evaluates the effect of silica modulus (Ms) and curing temperature on strengths and the microstructures of binary blended alkali-activated volcanic ash and limestone powder mortar. Mortar samples were prepared using mass ratio of combined Na2SiO3(aq)/10 M NaOH(aq) of 0.5 to 1.5 at an interval of 0.25, corresponding to Ms of 0.52, 0.72, 0.89, 1.05 and 1.18, respectively, and sole 10 M NaOH(aq). Samples were then subjected to ambient room temperature, and the oven-cured temperature was maintained from 45 to 90 °C at an interval of 15 °C for 24 h. The maximum achievable 28-day strength was 27 MPa at Ms value of 0.89 cured at 75 °C. Samples synthesised with the sole 10 M NaOH(aq) activator resulted in a binder with a low 28-day compressive strength (15 MPa) compared to combined usage of Na2SiO3(aq)/10 M NaOH(aq) activators. Results further revealed that curing at low temperatures (25 °C to 45 °C) does not favour strength development, whereas higher curing temperature positively enhanced strength development. More than 70% of the 28-day compressive strength could be achieved within 12 h of curing with the usage of combined Na2SiO3(aq)/10 M NaOH(aq). XRD, FTIR and SEM + EDX characterisations revealed that activation with combined Na2SiO3(aq)/10 M NaOH(aq) leads to the formation of anorthite (CaAl2Si2O8), gehlenite (CaO.Al2O3.SiO2) and albite (NaAlSi3O8) that improve the amorphosity, homogeneity and microstructural density of the binder compared to that of samples synthesised with sole 10 M NaOH(aq).

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Influence of MgO on Sintering and Property of Belite-Barium Calcium Sulphoaluminate Cement

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.152-154.68 ◽

2012 ◽

Vol 152-154 ◽

pp. 68-73

Author(s):

Ling Chao Lu ◽

Shou De Wang ◽

Hui Wang

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Compressive Strength ◽

Low Temperatures ◽

Sintering Process ◽

Sulphoaluminate Cement ◽

Calcium Sulphoaluminate ◽

Orthogonal Tests ◽

Calcium Sulphoaluminate Cement ◽

Curing Age

The effect of MgO on performance of belite-barium calcium sulphoaluminate cement (B-CBAS) was investigated through orthogonal tests. The results show that the formation of C3S can be improved at low temperatures by mixing MgO. SO3 decreasing the viscosity of fused mass in sintering process was beneficial to solid solution of MgO in B-CBAS clinker. The solid solubility of MgO in B-CBAS was higher than that of Portland cement, which indicated that high-magnesium limestone can be used in B-CBAS. Even MgO content reached 5.14%, the soundness of B-CBAS was still in safe, whose compressive strength at 3d and 28d curing age were 49.1MPa and 81.9MPa. This indicated that this kind of cement has good mechanical properties.

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Recovery of electron-irradiated zirconium at low temperatures

Canadian Journal of Physics ◽

10.1139/p68-047 ◽

1968 ◽

Vol 46 (5) ◽

pp. 321-324 ◽

Cited By ~ 19

Author(s):

H. H. Neely

Keyword(s):

Electrical Resistivity ◽

Low Temperature ◽

Electron Irradiation ◽

Low Temperatures ◽

Stage I ◽

Resistivity Change ◽

Low Oxygen ◽

Defect Migration ◽

Pair Annihilation ◽

Temperature Recovery

The low-temperature recovery of the electrical resistivity of polycrystalline zirconium was measured after electron irradiation below 8 °K. The material used in this irradiation was the same low oxygen material (0.015 at.%) used by Swanson to study recovery after deformation at 4.2 °K. Substage IB was found to be only of the order of 4% of the irradiation-induced resistivity change, compared to ~6% observed by Swanson after deformation. Stage I (4.2 to 160 °K) in Zr contains six substages, while stage II (160 to 310 °K) contains only one substage after electron irradiation. While no study of kinetics was made, it seems likely that close pair-annihilation processes are responsible for the recovery spectrum below 118 °K and that longer-range defect migration occurs in the neighborhood of 140 °K.

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