scholarly journals Corrigendum to “Comprehensive Effect of the Time and Water-Cement Ratio on the Rheological Properties of Power-Law Cement Grouts”

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-2
Author(s):  
Yang Zhi-Quan ◽  
Ding Yi ◽  
Mi Ya-Peng ◽  
Zhu Ying-Yan ◽  
Yang Yi ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Power Law ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Cement Grouts

scholarly journals Comprehensive Effect of the Time and Water-Cement Ratio on the Rheological Properties of Power-Law Cement Grouts

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yang Zhi-quan ◽  
Ding Yi ◽  
Mi Ya-peng ◽  
Zhu Ying-yan ◽  
Yang Yi ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Power Law ◽  
Great Influence ◽  
Exponential Model ◽  
Engineering Practice ◽  
Optimal Model ◽  
Cement Ratio ◽  
Consistency Coefficient ◽  
Water Cement Ratio ◽  
Cement Grouts

The rheological properties of cement grouts are significantly affected by the changes of the time and the water-cement ratio, which determine the diffusion state of grouts in rocks and soils and influence the outcome of projects. In this study, Portland cement grouts with water-cement ratios of 0.50, 0.55, 0.60, 0.65, 0.70, and 0.75 at six moments, including 0 minutes, 5 minutes, 10 minutes, 20 minutes, 30 minutes, and 60 minutes, were evaluated to figure out the comprehensive effect of the time and the water-cement ratio on the rheological properties of power-law cement grouts. The results showed that the water-cement ratio had a great influence on both the consistency coefficient and the rheological index of the power-law cement grouts. The former appeared to have a downward trend with the increase of the water-cement ratio, and the latter appeared to have an upward trend. There was a rising tendency between the time and the consistency coefficient, while the rheological index was less affected by time. The difference between its maximum and minimum values was within 5%. Combined with the perspectives of statistical theory, practical applicability, and accuracy, the exponential model was the optimal model for showing the relationship between the comprehensive effects of the time, water-cement ratio, and consistency coefficient of the power-law cement grouts. The linear model was the optimal model of the rheological index based on the comprehensive effect of time and the water-cement ratio. Based on this, a power-law rheological equation with consideration of the comprehensive effect of time and water-cement ratio was established. The research results could not only improve the rheological theory of power-law cement grouts but also provide technical support for engineering practice.

Research on Vibrating L-Box Test and Yield Value of Low Water-Cement Ratio Concrete

2021 ◽  
Vol 315 ◽  
pp. 120-127
Author(s):  
Xiao Tian Li ◽  
Zhu Rui Gao ◽  
Sheng Jun Zhang
Keyword(s):  
Flow Velocity ◽  
Rheological Properties ◽  
Vibration Frequency ◽  
Test Method ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Average Flow Velocity ◽  
Yield Value ◽  
Flow Morphology ◽  
The Relationship

The rheological properties of concrete have a great impact on the workability, and the L-box test can obtain the relationship between the morphology and the yield value of the material under free flow conditions. However, as an elastoplastic fluid, the low water-cement ratio concrete can hardly flow freely without the admixture. The vibrating process is often used in the production to meet the requirements, but the rheological properties of the material under vibration are difficult to measure. A new vibration test method for the flowability of low water-cement ratio concrete is proposed in combination with the L-box idea. The flow morphology and flow velocity of two kind of low water-cement ratio concrete in the L-box are observed under the condition of controlling the vibration frequency. After that, theoretically analyzing the yield value of the material under vibration is applied. The results show that with the increase of vibration frequency, the average flow velocity of the material increases, but the trend is gradually slower. With the increase of vibration frequency, the yield value of low water-cement ratio concrete is much lower than before. This test method can be used in related engineering applications of vibrating compacted concrete.

Effect of Molecular Weight of Polycarboxylate-type Superplasticizer on the Rheological Properties of Cement Pastes

2012 ◽  
Vol 20 (8) ◽  
pp. 725-736 ◽  
Author(s):  
Xiongyi Peng ◽  
Conghua Yi ◽  
Xueqing Qiu ◽  
Yonghong Deng
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
High Molecular Weight ◽  
High Efficiency ◽  
Rheological Behaviour ◽  
Low Molecular Weight ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Dispersing Ability

In order to study the effect of molecular weight of polycarboxylate-type superplasticizer (PC) on the rheological properties of cement pastes, PCs with different molecular weights (low, medium, high) were synthesized, and used as superplasticizers for cement suspensions. The effect of molecular weight of PC on the zeta potential, adsorption, and rheological behaviour of the corresponding cement suspensions were investigated systematically. Among the PCs, PC with a medium molecular weight always produced the lowest apparent viscosity for cement pastes at the same shear rate. Compared to PC with a low molecular weight, PC with a high molecular weight presented a stronger initial dispersing ability and a weaker dispersing stabilizing ability for cement pastes. In addition, PC with a low molecular weight had an advantage over PC with a high molecular weight for reducing the viscosity of paste in the low added dosage or low water/cement ratio, but the latter had the advantage of reducing the viscosity of the paste when the added dosage or water/cement ratio was high. This understanding of the rheological properties of cement pastes incorporating PC will provide an important reference for the application and synthesis of PC with high efficiency.

scholarly journals Influence of Water-Cement Ratio on Viscosity Variation of Cement Grout in Permeation Grouting

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Gaohang Lv ◽  
Jian Liu ◽  
Bo Han ◽  
Tiantao Zhang ◽  
Quanyi Xie ◽  
...  
Keyword(s):  
Relative Error ◽  
Apparent Viscosity ◽  
Cement Grout ◽  
Time Dependent ◽  
Permeation Grouting ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Dependent Behavior ◽  
Viscosity Variation ◽  
Cement Grouts

Diffusion radius is an important construction parameter, because it can significantly influence the grouting effectiveness. Theoretical models in predicting diffusion radius have been practiced, but there are still significant discrepancies between theoretical calculations and realistic results in the practical construction. One of the critical reasons for the misprediction is the time-dependent behavior of the cement grout, which is significantly affected by the water-cement ratio (W/C). Therefore, this paper experimentally and numerically studies the influence of W/C on the viscosity variation of the grout and grouting process. Firstly, the apparent viscosity of the cement grout under different W/C is tested by a rotational viscometer in a laboratory experiment. Subsequently, based on the laboratory tests, numerical models are established to investigate the influence of W/C on the diffusion process of cement grout in sand layers. According to the laboratory results, the apparent viscosity of cement grouts decreases with the increase of W/C. Besides, the apparent viscosity increases with time, while the increasing range of apparent viscosity firstly increases and then decreases as W/C increases. Based on the simulated results, when W/C changes from 0.8 to 1.1, the diffusion radius at 60 min experiences a less and less obvious increase under the given grouting pressure for permeation grouting in the sand layer. When W/C is 0.9, the relative error reaches to 37.65% at 60 min, which is slightly lower than that of 0.8. However, when W/C changes from 0.9 to 1.0, the relative error becomes very narrow (21.36%), and this figure is much lower than that of 0.8 or 0.9. The simulation results are verified by field test, and the relative error is 6%, which proves the effectiveness of the analysis. Therefore, the cement permeation model considering viscosity variation of the grout is a reasonable alternative in the real project. At the same time, the time-dependent behavior of cement grouts should be considered, especially when using cement grouts with a low water-cement ratio in the practical engineering.

Research on Time-Varying Behavior of Cement Grouts of Different Water-Cement Ratios

2011 ◽  
Vol 71-78 ◽  
pp. 4398-4401 ◽  
Author(s):  
Zhi Quan Yang ◽  
Ke Peng Hou ◽  
Ting Ting Guo
Keyword(s):  
Flow Pattern ◽  
Initial Stress ◽  
Power Law ◽  
Bingham Fluid ◽  
Time Varying ◽  
Power Law Fluid ◽  
Cement Ratio ◽  
Consistency Coefficient ◽  
Cement Grouts ◽  
Independent Behavior

The thesis presents an research on the time-varying behavior of cement grouts with different water-cement ratio of 0.5,0.55,0.6,0.65,0.7,0.75,0.8,0.9,1.0,1.1,1.25,1.0,2.0,5.0 and10.0 at 0 minute, 5minutes,10minutes,20minutes,30minutes,60minutes,respectively.This was to investigate the time-varying behavior of reheological parameters of cement grouts with different water-cement ratios.It confirmed that: consistency coefficient and viscosity are time-varying reheological parameters, while rheological index and initial stress(yield stress) are time-independent behavior;the flow pattern properties of cement grouts with different water-cement ratios could remain unchanged with time; the laws with time change of consistency coefficient and viscosity of cement grouts accord exponential function, cp(t)=c0×ekt (Power-law fluid) or hp(t)=h0×ekt(Newtonian fluid or Bingham fluid).These research results have very important realistic value and theory meaning.

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