Detection of setting time in cement hydration using patch antenna sensor

2021 ◽  
Author(s):  
Zhuoran Yi ◽  
Songtao Xue ◽  
Liyu Xie ◽  
Guochun Wan
Keyword(s):  
Patch Antenna ◽  
Cement Hydration ◽  
Setting Time

scholarly journals Effect of TiO2 Nanoparticles on Physical and Mechanical Properties of Cement at Low Temperatures

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Li Wang ◽  
Hongliang Zhang ◽  
Yang Gao
Keyword(s):  
Mechanical Properties ◽  
Low Temperatures ◽  
Cement Hydration ◽  
Setting Time ◽  
Physical And Mechanical Properties ◽  
Xrd Analysis ◽  
Cementitious Materials ◽  
Strength Test ◽  
Hydration Degree ◽  
Time Test

Low temperature negatively affects the engineering performance of cementitious materials and hinders the construction productivity. Previous studies have already demonstrated that TiO2 nanoparticles can accelerate cement hydration and enhance the strength development of cementitious materials at room temperature. However, the performance of cementitious materials containing TiO2 nanoparticles at low temperatures is still unknown. In this study, specimens were prepared through the replacement of cement with 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.% TiO2 nanoparticles and cured under temperatures of 0°C, 5°C, 10°C, and 20°C for specific ages. Physical and mechanical properties of the specimens were evaluated through the setting time test, compressive strength test, flexural strength test, hydration degree test, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) analysis, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) in order to examine the performance of cementitious materials with and without TiO2 nanoparticles at various curing temperatures. It was found that low temperature delayed the process of cement hydration while TiO2 nanoparticles had a positive effect on accelerating the cement hydration and reducing the setting time in terms of the results of the setting time test, hydration degree test, and strength test, and the specimen with the addition of 2 wt.% TiO2 nanoparticles showed the superior performance. Refined pore structure in the MIP tests, more mass loss of CH in TGA, intense peak appearance associated with the hydration products in XRD analysis, and denser microstructure in SEM demonstrated that the specimen with 2 wt.% TiO2 nanoparticles exhibited preferable physical and mechanical properties compared with that without TiO2 nanoparticles under various curing temperatures.

scholarly journals Influence of Organic Esters on Portland Cement Hydration and Hardening

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Duan-le Li ◽  
Da-peng Zheng ◽  
Dong-min Wang ◽  
Ji-hui Zhao ◽  
Cheng Du ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Cement Hydration ◽  
Setting Time ◽  
Exothermic Peak ◽  
Hardened Cement ◽  
Test Results ◽  
Trimethyl Phosphate ◽  
Cement Slurry ◽  
Hydration Degree ◽  
Dimethyl Oxalate

This paper investigated the effect of organic compounds with ester groups on the hydration and hardening of cement. The effects of five kinds of organic compounds with ester groups (ethyl acetate, dimethyl oxalate, glyceryl triacetate, trimethyl phosphate, and triethanolamine borate) on hydration heat, hydration degree, setting time, mechanical properties, microstructure, and pore structure of hardened cement slurry were studied. The test results showed that esters can make the end time of cement hydration induction longer and delay the occurrence of the second exothermic peak. Also, the effect of five kinds of esters on the hydration and hardening of cement was basically followed by TG> TB> DMO> EAC> TMP. In terms of molecular structure, for organic compounds containing only ester groups, the higher the number of ester groups, the greater the effect on the hydration of cement. The introduction of other functional groups (such as phosphate or borate) will influence the effect of the esters.

Influence of Clutch Disc Waste (Grinding Dust) on Portland Cement Hydration

2019 ◽  
Vol 803 ◽  
pp. 284-288
Author(s):  
José da Silva Andrade Neto ◽  
Tiago Assunção Santos ◽  
Raphael Dias Mariano ◽  
Marcio Raymundo Morelli ◽  
Daniel Véras Ribeiro
Keyword(s):  
Portland Cement ◽  
Propagation Velocity ◽  
Pulse Propagation ◽  
Cement Hydration ◽  
Setting Time ◽  
Reference Sample ◽  
Ultrasonic Pulse ◽  
X Ray Diffraction ◽  
Copper Zinc ◽  
Portland Cement Hydration

This paper evaluates the effect of grinding dust (GD), a waste generated in the clutch disc finishing process, on Portland cement hydration. For this, pastes with additions of 5%, 10% and 15% GD, relative to cement weight, were molded and compared with a reference sample. Tests of setting time determination by Vicat needle, calorimetry, monitoring the ultrasonic pulse propagation velocity and mineralogical analysis (X-ray diffraction) in pastes with 1 day of hydration were carried out. It was observed that GD, due to the presence of copper, zinc and phenolic resin in its composition, is responsible for retarding cement hydration and thus increases the setting time and delays the evolution of heat release and pulse propagation velocity. However, the formation of new crystalline phases was not observed.

Modification Effects of Nano-CaCO3 on Engineering Performance of Cement Grouts

2020 ◽  
Vol 20 (8) ◽  
pp. 5043-5048
Author(s):  
Xiang Qiu ◽  
Huangbin Jiang ◽  
Guijin Zhang
Keyword(s):  
Yield Stress ◽  
Cement Hydration ◽  
Setting Time ◽  
X Ray Diffraction ◽  
Bleeding Rate ◽  
X Ray ◽  
Initial Setting Time ◽  
Study Results ◽  
Initial Setting ◽  
Cement Grouts

Efficacy of added nano-CaCO3 (NC) on engineering performances, including fluidity, initial setting time, bleeding rate and yield stress of cement grouts was investigated in this study. Results showed that the fluidity and bleeding rate for NC-cement (NCC) composite grout first decreased with increased NC content (i.e., ratio of NC mass to cement mass) and then slightly recovered as the NC content exceeded 2%. The initial setting time was always reduced while the yield stress increased with increased NC content. The microstructure of NCC was analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the NC can promote the cement hydration, but an excess amount of NC will inhibit the cement hydration and affect the engineering performances of cement grouts. The optimum NC content for modification of cement grouts was thus 2%.

Effect of Citric Acid on Cement Hydration

2011 ◽  
Vol 393-395 ◽  
pp. 49-53 ◽  
Author(s):  
Bao Guo Ma ◽  
Jun Xiao ◽  
Hong Bo Tan
Keyword(s):  
Citric Acid ◽  
Cement Hydration ◽  
Setting Time ◽  
Initial Setting Time ◽  
Final Setting Time ◽  
Retarding Effect ◽  
Initial Setting ◽  
Flow Loss ◽  
Diffraction Peaks ◽  
Acid Dosage

Through the test of citric acid of cement paste, setting time and compression strength changes, and combined with XRD, SEM, discusses the influence of citric acid on cement hydration process. The results show that: citric acid can effectively increase the initial cement fluidity, when the content is exceed to 0.1%, the 60 min flow loss of increased gradually. Citric acid retarding effect increases with dosage, but there is a critical dosage, when the dosage is less than 0.1%, the initial setting time and final setting time increased slowly; When the dosage more than 0.1%, the initial setting time increased slowly, but the final setting time increases rapidly; With the increase in citric acid dosage, AFt diffraction peaks increases, while the CH peak decreases, indicating that the citric acid accelerated the initial hydration of C3A, while inhibiting C3S hydration and promoting AFt generation

Study on Impermeability Mechanism of Magnetic Water Concrete

2011 ◽  
Vol 99-100 ◽  
pp. 745-748 ◽  
Author(s):  
Yi Xin Wang ◽  
Xuan Wang ◽  
Zeng Ke Yang
Keyword(s):  
Cement Hydration ◽  
Setting Time ◽  
Hardening Process ◽  
Water Ratio ◽  
Magnetic Water

The magnetic water can increase the strength of concrete, which can infer that the impermeability of concrete has been improved. According to the reason of permeation of concrete and on the basis of the study of magnetic water concrete by the predecessors, the effects such as hypothesis of the mechanism, action of the cement hydration, concrete workability, water ratio of the concrete, setting time and hardening process on impermeability of magnetic water concrete was studied in this issue. And the mechanism of impermeability of magnetic water concrete is also analyzed.

scholarly journals NRG COSIA Carbon XPRIZE: carbon-dioxide mineralization in recycled concrete wash water

Clean Energy ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 553-574
Author(s):  
Sean Monkman ◽  
Travis Janke ◽  
Alex Hanmore
Keyword(s):  
Suspended Solids ◽  
Cement Hydration ◽  
Setting Time ◽  
Recycled Concrete ◽  
Wash Water ◽  
Concrete Production ◽  
Carbon Dioxide Mineralization ◽  
A Site ◽  
Ready Mixed Concrete ◽  
Co2 Treatment

Abstract Wash water is generated as a waste stream from ready-mixed-concrete production. Reuse of the water as mixture water is limited, in practice, by the negative material performance impacts associated with the water chemistry and properties; the effects are intensified with increasing content of suspended solids and age. However, this waste material can be used as a beneficial additive to concrete by profiting from the cementitious properties of the suspended solids, if variability can be reduced. A method of stabilizing this material is through CO2 treatment. The added CO2 is mineralized through a reaction with the calcium from the cement particles. This provides a calcium-carbonate coating that prevents further cement hydration, making the material predictable. This has been shown to alleviate concerns with set acceleration and inconsistencies in compressive strength. A method of CO2 treatment was tested as part of the NRG COSIA Carbon XPRIZE at a site in Calgary, Alberta. The slurry for the treatment was provided by a local concrete plant and had a specific gravity of 1.15. The simulated wash water was treated in 1000-L quantities with each treatment mineralizing an average of 40 kg of CO2. The system ran for 1600 hours of operation over 127 treatment cycles and converted 14.5 tonnes of CO2 at an average mineralization efficiency of 80%. The treated slurry was used as an additive in >300 batches of concrete where the concrete met the necessary requirements for fresh properties and setting time, while achieving a strength benefit. Replacement of 5% and 10% of batch water with treated slurry (9.4 and 18.8 kg slurry/m3 concrete) showed a strength benefit of 3% and 6% compared to a reference. The technology was selected as the winner of the NRG COSIA Carbon XPRIZE (Track B: Natural Gas) in April 2021.

Retarding Action of Various Lead (II) Salts on Setting of Portland Cement

2018 ◽  
Vol 760 ◽  
pp. 43-48
Author(s):  
Martin Keppert
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Hydration ◽  
Setting Time ◽  
Lead Sulfate ◽  
Cementitious Material ◽  
Secondary Product ◽  
Experimental Conditions ◽  
Anion Effect ◽  
High Instability

Lead is an example of heavy metal, which influences the course of silicate cement hydration resulting to retardation of setting and hardening. This topic become of importance when a cementitious material is intended to be used as solidification/stabilization matrix for a waste or secondary product containing some lead species. There are literature data on the effect of Pb retarding action but they are incomparable each other due to uneven experimental conditions, used Pb salts, types of cement etc. The present paper aims to describe influence of various lead(II) compounds (nitrate, sulfate and lead(II) oxide) on setting course of Ordinary Portland cement (OPC). The setting was monitored by Vicat apparatus, the dosage of salts (expressed as wt. % of elementary Pb to OPC) was 0.5, 1, 2 and 5%. Obviously the present anions may also influence the setting time; the set of control experiments with sodium salts of above given anions was performed in order to eliminate the anion effect. The PbO was found to be most detrimental towards retarding of setting, while lead sulfate at higher dosages caused high instability of setting (oscillation). The effect of Pb was, in all cases, more important than influence of given anion.

scholarly journals Hydration Properties of Portland Cement Paste with Boron Gangue

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Quan Zhao ◽  
Jianwei Tu ◽  
Weiwei Han ◽  
Xi Wang ◽  
Youzhi Chen
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Setting Time ◽  
High Strength ◽  
Cementitious Materials ◽  
Radiation Shielding ◽  
Boron Compounds ◽  
Hydration Properties ◽  
Materials Used ◽  
Low Solubility

In order to prepare a good radiation shielding concrete with a proper setting time and a high strength, the hydration properties of cement with boron gangue were investigated by the methods of XRD, isothermal microcalorimetry, TG/DSC, and FTIR. The results demonstrated that it was mainly related to the insoluble matter CaB2O4·4H2O and Ca(H2BO3)2·4H2O that boron gangue could severely inhibit the cement hydration. Boron gangue made a significant retardation on Portland cement hydration with the form of BO33− and BO45−, which caused an obvious retardation of C3A and C3S hydration with an insoluble coat and a low solubility of calcium ion in the solution. Therefore, it is important and necessary to take into consideration the chemistry of borates in aqueous and the kind of cement-based or cementitious materials used for radiation shielding concrete with boron or boron compounds, especially for the materials with a high content of C3A and C3S.

scholarly journals Parameter Study of Superabsorbent Polymers (SAPs) for Use in Durable Concrete Structures

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1541 ◽  
Author(s):  
Laurence De Meyst ◽  
Els Mannekens ◽  
Maria Araújo ◽  
Didier Snoeck ◽  
Kim Van Tittelboom ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cement Hydration ◽  
Setting Time ◽  
Concrete Structures ◽  
Parameter Study ◽  
Particle Sizes ◽  
Hydration Kinetics ◽  
Superabsorbent Polymers ◽  
Swelling Capacity ◽  
Cross Linker

Superabsorbent polymers (SAPs) can be added to a concrete mixture to provide internal curing and reduce the risk for early-age shrinkage cracking. Hence, they can help to increase the overall durability of concrete structures. The type, swelling characteristics, kinetics of water release, amount and particle size of the SAPs will dictate their effectiveness for this purpose. In this paper, SAPs with different cross-linking degrees, particle sizes and amount of solubles are investigated. By varying these parameters, insight can be gained on the influence of each of these parameters on SAP properties such as the swelling capacity. In a next step, the SAPs can be implemented in mortar to assess their influence on mortar properties like workability, compressive strength or hydration kinetics. Based on these results, the ‘ideal’ SAP with tunable properties for a specific concrete application can be selected. For this purpose, an anionic SAP was synthesized with varying amounts of cross-linker and ground to particle sizes with d50 varying between 10 and 100 µm. The swelling capacity in demineralised water of 40 µm SAP particles increased with a decreasing degree of cross-linker from 66 g/g SAP with 1 mol% cross-linker to 270 g/g SAP in case of 0.15 mol% cross-linker, and was about three to four times larger than the swelling capacity in the prepared cement filtrate. The SAPs were tested for their effect on mortar workability, cement hydration kinetics and mechanical properties of the hardened mortar. With proper compensation for the absorbed water by the SAPs, the mortar workability was not negatively affected and the reduction in flow over the first two hours remained limited. The SAPs with the lowest swelling capacity, resulting in the smallest total amount of macro pores formed, showed the smallest negative effect on mortar compressive strength (a reduction of 23% compared to the reference after 28 days for an addition of 0.5 m% SAP) and a negligible effect on cement hydration. The difference in strength with the reference decreased as a function of mortar age. When using SAPs with particle sizes in the range of 10–100 µm, no significant differences between the studied particle sizes were found concerning the mortar properties. With the ease of upscaling in mind, the need to purify the SAPs and to remove the non-cross-linked soluble fraction was further investigated. It was shown that the solubles had no effect on the mortar properties, except for increasing the setting time with almost 100%.

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