scholarly journals Improving the Mechanical Properties of Sulfoaluminate Cement-Based Grouting Material by Incorporating Limestone Powder for a Double Fluid System

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4854 ◽  
Author(s):  
Yanfeng Wang ◽  
Songhui Liu ◽  
Dongxing Xuan ◽  
Xuemao Guan ◽  
Haibo Zhang
Keyword(s):  
Compressive Strength ◽  
Reaction Rate ◽  
Setting Time ◽  
Limestone Powder ◽  
Hydration Reaction ◽  
Replacement Rate ◽  
Early Hydration ◽  
Nucleation Effect ◽  
Grouting Material ◽  
Late Stages

To improve the hardening performance of sulfoaluminate cement-based grouting material (SCGM) and reduce its cost, limestone powder was adopted to replace anhydrite in the control SCGM. The influence of the replacement rate of limestone powder on the hydration, hardening strength, expansion, and microstructure evolution of the SCGM was systematically researched. The results indicated that replacing anhydrite with limestone powder in SCGM can improve the flowability, shorten the setting time, and enhance the compressive strength at early and late stages. When the replacement rate of limestone powder was 20%, the compressive strength of SCGM for 6 h and 28 days increased by 146.41% and 22.33%, respectively. These enhancements were attributed to the fact that fine limestone powder can accelerate the early hydration reaction rate and promote the formation of ettringite due to its nucleation effect. Moreover, due to the presence of limestone powder, mono-carbonate (Mc) can be formed, which would densify the microstructure and refine the pore structure of the hardened SCGM.

Influence of Glass and Limestone Powders in High Calcium Fly Ash Geopolymer Paste on Compressive Strength and Microstructure

2019 ◽  
Vol 801 ◽  
pp. 397-403
Author(s):  
Pattanapong Topark-Ngarm ◽  
Tawatchai Tho-In ◽  
Vanchai Sata ◽  
Prinya Chindaprasirt ◽  
Trinh Cao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Glass Powder ◽  
Sodium Hydroxide Solution ◽  
Setting Time ◽  
Limestone Powder ◽  
Hydration Reaction ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Geopolymer Paste

The effects of replacing high calcium fly ash with containment glass powder and limestone powder in the geopolymer are investigated in this paper. The high calcium fly ash was replaced by either glass powder or limestone powder at 20% and 40% by weight. The geopolymer paste was tested for setting time and compressive strength and evaluated of its microstructure on SEM, XRD, FTIR, and MIP. The results indicated that the setting time of geopolymer paste was increased with the replacement of glass powder and reduced by replacement of limestone powder. The compressive strengths were generally higher than those of controls. The maximum increase of compressive strength was 33% when replaced fly ash with 20% of glass powder at 8 molar NaOH concentration of sodium hydroxide solution. The microstructure evaluations show the remaining particles of raw materials and the compatible of hydration reaction and polymerization when having limestone powder in the mix proportion. Furthermore, the powder acts as a filler in the gels.

Study on the Performance of Machine-Made Sand Concrete Combined Admixture of Limestone Powder and Substandard Fly Ash

2011 ◽  
Vol 99-100 ◽  
pp. 786-789
Author(s):  
Guo Qiang Xu ◽  
Lin Gao ◽  
Hai Xia Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Diffraction Peak ◽  
Limestone Powder ◽  
Hydration Reaction

This paper adopted combined admixture of limestone powder and substandard fly ash to prepare the machine-made sand concrete, and studied its performance, compressive strength and micro-properties. The results showed that this kind of machine-made sand concrete owned a good performance, for its 60min slump loss within the range of 15mm to 85mm; the changes in the ratio of limestone powder to low-quality fly ash had little effect on the its compressive strength; with the increase of the ratio between limestone powder and low-quality fly ash, the Ca(OH)2 diffraction peak also increased; when hydration was up to 120d, the limestone powder was not involved in the hydration reaction.

scholarly journals Effect of Nanosilica on the Fresh Properties of Cement-Based Grouting Material in the Portland-Sulphoaluminate Composite System

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shengli Li ◽  
Tingting Xu
Keyword(s):  
Particle Size ◽  
Apparent Density ◽  
Composite System ◽  
Setting Time ◽  
Xrd Analysis ◽  
Hydration Reaction ◽  
Particle Sizes ◽  
Fresh Properties ◽  
Air Content ◽  
Grouting Material

The effect of NS particle size and content on the fresh properties of the grouting material based on the portland-sulphoaluminate composite system was analyzed. The experimental results indicated that air content increased and apparent density decreased, with increased NS content, but the NS particle sizes have minimal effect on the air content and apparent density. The setting time of mortar was significantly shortened, with increased NS content; however, NS particle sizes had little influence on the setting time. The effect of fluidity on the mortars adding NS with particle size of 30 nm is larger than NS with particle sizes of 15 and 50 nm and the fluidity decreased with increased NS content, but the fluidity of mortars with the particle sizes of 15 and 50 nm is almost not affected by the NS content. XRD analysis shows that the formation of ettringite was promoted and the process of hydration reaction of cement was accelerated with the addition of NS. At the microscopic level, the interfacial transition zone (ITZ) of the grouting material became denser and the formation of C-S-H gel was promoted after adding NS.

scholarly journals Experimental Study on the Influence of PVA Content on the Performance of Grouting Material in Deep Stope

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Bin Liu ◽  
Liming Yin ◽  
Juntao Chen ◽  
Ming Li ◽  
Daozeng Tang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Setting Time ◽  
Practical Significance ◽  
Peak Period ◽  
Grouting Material ◽  
Coupling Characteristics ◽  
Grouting Materials ◽  
And Control ◽  
Water Hazards

Based on laboratory experiments, the paper researches the effect of polyvinyl alcohol (PVA) content on the performance of fly ash-based cement grouting materials. The test results show that the addition of PVA has limited effect on the initial and final setting time and brings a certain but minor delay on the appearance of the hydration peak period. It enhances cement hydration during the hydration slow down period. The impermeability of PVA to the grouting material is obviously improved, and it increases with the growing amount of PVA content. PVA improves the flexural strength and compressive strength of the sample block to varying degrees, and the improvement on flexural strength is more obvious than that on the compressive strength. It has a significant effect on the mechanical properties of the grouting material and can effectively improve the rock mass’s hydraulic coupling characteristics. It also has great application value and practical significance for the prevention and control of water hazards in deep coal stopes.

scholarly journals Effect of Sodium Aluminate Dosage as a Solid Alkaline Activator on the Properties of Alkali-Activated Slag Paste

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Bin Chen ◽  
Jun Wang ◽  
Jinyou Zhao
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Setting Time ◽  
Sodium Aluminate ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Alkali Activated Slag ◽  
Alkaline Activator ◽  
Activated Slag ◽  
Alkali Activated

Extensive research into alkali-activated slag as a green gel material to substitute for cement has been done because of the advantages of low-carbon dioxide emissions and recycling of industrial solid waste. Alkali-activated slag usually has good mechanical properties, but the too fast setting time restricted its application and promotion. Changing the composition of alkaline activator could optimize setting time, usually making it by adding sodium carbonate or sodium sulfate but this would cause insufficient hydration reaction power and hinder compressive strength growth. In this paper, the effect of sodium aluminate dosage as an alkaline activator on the setting time, fluidity, compressive strength, hydration products, and microstructures was studied through experiments. It is fair to say that an appropriate amount of sodium aluminate could obtain a suitable setting time and better compressive strength. Sodium aluminate provided enough hydroxyl ions for the paste to promote the hydration reaction process that ensured obtaining high compressive strength and soluble aluminium formed precipitate wrapped on the surface of slag to inhibit the hydration reaction process in the early phase that prolonged setting time. The hydration mechanism research found that sodium aluminate played a key role in the formation of higher cross-linked gel hydration products in the late phase of the process. Preparing an alkali-activated slag with excellent mechanical properties and suitable setting time will significantly contribute to its application and promotion.

Effect of Anhydrite on the Early Hydration Performance of Rapid Setting and Hardening Belite Sulfoaluminate Cement

2017 ◽  
Vol 898 ◽  
pp. 1990-1995 ◽  
Author(s):  
Ming Zhang Lan ◽  
Bin Feng Xiang ◽  
Jian Feng Wang ◽  
Xu Dong Zhao ◽  
Xiao Ying Wang
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
High Strength ◽  
Cement Clinker ◽  
Hydration Kinetics ◽  
Early Hydration ◽  
Free Lime ◽  
Calcium Sulfoaluminate ◽  
Setting Times ◽  
Rapid Setting

In order to investigate the early hydration behavior of rapid setting and hardening belite sulfoaluminate cements, the methods of X-ray Diffraction, Scanning Electron Microscope, Compressive Strength test and Setting Times test were used to identify and quantify the hydration kinetics and microstructure of this new-found cements in China. The results showed that the main mineral compositions of high belite sulfoaluminate cement clinker included calcium sulfoaluminate (4CaO·3Al2O3·CaSO4), belite (2CaO·SiO2), ferrite phase, free gypsum and free lime. It was found that not only the setting time and compressive strength but also the composition of hydration products were influenced by anhydrite to some extent. Meanwhile, a mass of AFt and AFm generated along with the hydration process at different ages, overlapped, crossed and penetrated through calcium silicate hydrate gel and aluminum oxide to form a relatively dense structure which could contribute to the high strength of cement.

scholarly journals Effect of Gypsum on Hydration and Hardening Properties of Alite Modified Calcium Sulfoaluminate Cement

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3131 ◽  
Author(s):  
Pei Li ◽  
Zhiqiang Ma ◽  
Zhong Zhang ◽  
Xumin Li ◽  
Xiaolei Lu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Calcium Sulfoaluminate Cement ◽  
Experimental Conditions ◽  
Calcium Sulfoaluminate ◽  
Ion Doping ◽  
Iron Phase ◽  
Calcium Sulphoaluminate ◽  
Barium Ion ◽  
Late Stages

Calcium sulphoaluminate cement (CSA) has the characteristics of quick hardening, high early strength and high impermeability, however its strength growth persistence in the middle and late stages (after the age of 3 days) is poor. In order to improve this disadvantage, the pilot production of alite (C3S) modified CSA (AMCSA) clinker was carried out by liquid phase manipulation and barium ion doping technology. The effects of different dosages of gypsum on the hydration and hardening properties of AMCSA, such as setting time, hydration rate, compressive strength and hydration products, were studied. The results show that the mineral content of ye’elimite, C2S, C3S and iron phase in the calcined AMCSA clinker are 48.5 wt.%, 32.6 wt.%, 11.7 wt.% and 7.2 wt.% respectively, which are close to the designed mineral composition. The stable coexistence of ye’elimite and C3S in the same clinker system is realized. The initial and final setting time of AMCSA are retarded with the increasing gypsum dosage. When the gypsum dosage is 15 wt.% under the experimental conditions in this study, the AMCSA mortar reaches the highest compressive strength at every age. The strength of AMCSA mortar at 28 days is still significantly improved compared with that at 3 days, which indicates that the shortcoming of the low strength growth persistence of CSA in the middle and late stages is improved.

scholarly journals Evaluation of the Effect of Fly Ash on Hydration Characterization in Self-Compacting Concrete (SCC) at Very Early Ages Using Piezoceramic Transducers

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2489 ◽  
Author(s):  
Yu Zheng ◽  
Dongdong Chen ◽  
Lingzhu Zhou ◽  
Linsheng Huo ◽  
Hongwei Ma ◽  
...  
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Penetration Resistance ◽  
Electrical Signal ◽  
Experimental Results ◽  
Early Age ◽  
Hydration Reaction ◽  
Test Results ◽  
Self Compacting Concrete ◽  
Early Hydration

Nowadays, the industrial waste, Fly Ash (FA), as a mineral admixture or a replacement of cement for the production of self-compacting concrete (SCC) has been increasingly used, because of its benefits in enhancing both fresh and long-term concrete properties and in promoting environmental-friendly construction. In this study, the conventional cement was replaced by FA at different rates (0%, 20%, 40%, 60% of the cement mass) for the SCC mixtures. The early-age (0–24 h) SCC hydration, which is a complicated chemical reaction in pozzolanic behavior, was characterized by using a pair of piezoceramic Smart Aggregates (SAs). One SA works as an actuator and the other works as a sensor. A sweep sine signal from 100 Hz to100 kHz was used as the excitation signal, which is helpful to understand the quantitative influence of fly ash on the kinetics of SCC hydration. During the hydration reaction, the received electrical signal was continuously detected by the sensor. The experimental results showed that increasing the volume of fly ash resulted in longer pozzolanic reaction time in SCCs, which successfully reveals the effect of fly ash volume on the hydration behavior in early age (0–24 h) hydration. In order to quantitatively evaluate the hydration in the 0–24 h, based on the wavelet packet energy analysis, the hydration completion index (HCI) and normalized hydration completion index (NHCI) were defined. The experimental results showed that the NHCI can clearly reveal the hydration completion progress during the early hydration age (0–24 h). To validate the accuracy of the test results based on SAs, a series of mechanical tests for penetration resistance of SCCs with different volumes of fly ash were carried out. The results predicted by the signal based on SAs gave reasonable agreement with the test results of penetration resistance. It can be concluded that a successful investigation of the influence of fly ash on early-age SCC hydration response can be achieved based on the analysis of the received electrical signal using the proposed method and the important hydration characteristics, such as initial and final setting time, and can be approximately predicted by NHCI values.

Properties of Grouting Mortar Modified with Alunite/Bauxite/Gypsum Ternary System as Expansion Component

2013 ◽  
Vol 815 ◽  
pp. 839-844
Author(s):  
Yin Suo Dai ◽  
Jian Dang Ding ◽  
Yue Hu Tan ◽  
Xiao Jun Yuan ◽  
Chun Hua Lu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Ternary System ◽  
Volume Expansion ◽  
Setting Time ◽  
First Aid ◽  
Microscopic Structure ◽  
Pullout Force ◽  
Grouting Material ◽  
Important Basis

The ettringite results from alunite/bauxite and gypsum which has the characteristic of fast setting and volume expansion, so the main properties and microscopic structure of grouting material modified with alunite/bauxite and gypsum at different proportion were investigated. The results have shown that the grouting mortar modified with 7-20% content of bauxite/alunite/gypsum had the properties such as the setting time could be controlled below 1 hour, long-term expansion rate stabilized basically as 0.2%, compressive strength of 1, 3 and 14 days were more than 17 MPa, 31 MPa and 50 MPa, respectively; the pullout force of 1 meter sample at 14 days reached 87 kN. The micro-analyzing by using MIP, SEM and XRD showed that there were plenty of expansive crystals and tiny pore structures in harded paste which can exist steadily for a long term. The achievements will provide an important basis to application of cement-based grouting material as first-aid repairing.

Research on the Compound early Strength Agent to the Performance of Super High early Strength Grouting Material

2013 ◽  
Vol 477-478 ◽  
pp. 996-1001 ◽  
Author(s):  
Xiao Ping Zhang ◽  
Chang Zheng Sun ◽  
Tong Feng Zhao
Keyword(s):  
Compressive Strength ◽  
Sodium Sulfate ◽  
Setting Time ◽  
Cementitious Material ◽  
Final Setting Time ◽  
Grouting Material ◽  
Reinforcement Material ◽  
Reasonable Proportion ◽  
Strength Material ◽  
Early Strength

The effect of sodium sulfate, triethanolamine and early strength agent A on the early strength reinforcement material final setting time, flexural strength and compressive strength and structure were investigated. The results show that the composite of sodium sulfate, triethanolamine and early strength agent according to a reasonable proportion, the dosage of 0.35% -0.40% (in cementitious material quality), the final setting time of early strength material for 50 to 60 min, Initial fluidity over 320mm, 0.5h flow degree greater than 280mm, 1d bending greater than 12MPa and 28d compressive strength greater than 80MPa, meet the requirements.

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