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

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.

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The effect of water/cement ratio, plasticizers and temperature on the rheology of cement grouts

Advances in Cement Research ◽

10.1680/adcr.1988.1.4.195 ◽

1988 ◽

Vol 1 (4) ◽

pp. 195-206 ◽

Cited By ~ 8

Author(s):

P. L. Domone ◽

H. Thurairatnam

Keyword(s):

Cement Ratio ◽

Water Cement Ratio ◽

Effect Of Water ◽

Cement Grouts

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Experimental Study on Groutability of Sand Layer concerning Permeation Grouting

Advances in Materials Science and Engineering ◽

10.1155/2021/6698263 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Yan-Xu Guo ◽

Qing-Song Zhang ◽

Lian-Zhen Zhang ◽

Ren-Tai Liu ◽

Xin Chen ◽

...

Keyword(s):

Particle Size ◽

Relative Density ◽

Clay Content ◽

Sand Particle ◽

Sand Layer ◽

Permeation Grouting ◽

Cement Ratio ◽

Water Cement Ratio ◽

Grouting Pressure ◽

Relative Density Of Sand

Permeation grouting is widely used in grouting engineering because of its low grouting pressure and minor disturbance to the stratum. However, influenced by the complex properties of sand layer and slurry, an accurate prediction of the groutability of the sand layer remains to be a hard work. In this paper, the permeability of sand layer is studied based on a self-designed permeation grouting test device, which considers the different sand particle size, relative density of sand layer, slurry water-cement ratio, and clay content. The influencing factors of sand layer groutability are analyzed, and the different parameters that affect the grouting of sand layer are evaluated, thus proposing a new approach to predict the groutability of sand layer. Results show that the sand particle size and slurry water-cement ratio are positively related to the groutability of sand layer, and the relative density and clay content of sand layer are negatively correlated with the groutability of sand layer. The proposed alternative empirical formula to estimate the groutability of sand layer will help predict the groutability of sand layer with a higher degree of accuracy, which can provide a certain reference for engineering.

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

Geofluids ◽

10.1155/2021/6636708 ◽

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.

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Clay dosage and water/cement ratio of clay-cement grout for optimal engineering performance

Applied Clay Science ◽

10.1016/j.clay.2018.07.035 ◽

2018 ◽

Vol 163 ◽

pp. 312-318 ◽

Cited By ~ 15

Author(s):

Cong Zhang ◽

Junsheng Yang ◽

Xuefeng Ou ◽

Jinyang Fu ◽

Yipeng Xie ◽

...

Keyword(s):

Cement Grout ◽

Cement Ratio ◽

Water Cement Ratio

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Research on Influence of Water-Cement Ratio on Reinforcement Effect for Permeation Grouting in Sand Layer

Advances in Materials Science and Engineering ◽

10.1155/2020/5329627 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Zhipeng Li ◽

Lianzhen Zhang ◽

Yuntian Chu ◽

Qingsong Zhang

Keyword(s):

Deformation Modulus ◽

High Water ◽

Sand Layer ◽

Curing Time ◽

Reinforcement Effect ◽

Cement Slurry ◽

Permeation Grouting ◽

Cement Ratio ◽

Water Cement Ratio ◽

Grouting Reinforcement

In order to study permeation grouting reinforcement effect in the sand layer, a set of grouting test device is developed, which consists of a power device, a pressure-bearing slurry tank, and several test frames. Compressive strength, deformation modulus, and permeability coefficient are selected to be the evaluation index of grouting reinforcement effect. Grouting reinforcement effect under different water-cement ratio of cement slurry and curing time were measured. Eventually, under laboratory conditions, fitting formulas have been obtained which describe the quantitative relationship between reinforcement effect of permeation grouting and water-cement ratio and curing time. Results show that water-cement ratio of slurry has obvious effect on grouting reinforcement effect. Mechanical performance and impermeability of the grouted body are negative-correlated with water-cement ratio. There are two different destruction patterns for the grouted body in uniaxial compression process: global destruction pattern at low water-cement ratio and local destruction pattern at high water-cement ratio. If cement slurry at high water-cement ratio is permeated into the sand layer, water bleeding phenomena will appear and lead to inhomogeneous performance of the grouted body, with lower performance in the upper part and higher performance in the lower part of the grouted body.

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Investigations on Improving the Compressive Strength of Sand Column with Cement Grout and Chemical Admixture

Turkish Journal of Computer and Mathematics Education (TURCOMAT) ◽

10.17762/turcomat.v12i2.1522 ◽

2021 ◽

Vol 12 (2) ◽

pp. 1841-1847

Author(s):

M. Samuel Thanaraj, Et. al.

Keyword(s):

Compressive Strength ◽

Internal Friction ◽

Water Content ◽

Soil Improvement ◽

Cement Grout ◽

Sand Column ◽

Cement Ratio ◽

Water Cement Ratio ◽

Angle Of Internal Friction ◽

Chemical Admixture

Grouting is one of the most commonly adopted technique for soil improvement and strengthening. Adding super plasticizers, accelerators, antifreezes, air entraining agent improves the performance of the cement grout. The performance of the grout while injecting in the sand column mainly depends on its fluidity property. Keeping it in mind about the water cement ratio, the strength of the sand column is studied in two sets of experiments one by sand column with cement grout only and another set by sand column with cement grout added with super plasticizers by varying the water cement ratios. Strength parameters like angle of internal friction and cohesion were obtained be direct shear test and unconfined compressive strength test on the specimens by varying the water content. An increase of 15.2kPa to 60.33 kPa was observed in the cohesion value for specimens with 10% water content and 13.8 kpa to 47.2kPa cohesion value observed in the specimens with 20% water content. The angle of internal friction was decreased from 360 to 160 for 10% water content whereas 300 to 100 for 20% water content. A series of experiments were conducted on the sand column grouted with cement and for different water cement ratios as 1.5, 2.0 and 2.5. Another set of experiments were repeated by adding 2%super plasticizer Sulphonated Melamine Formaldehyde (SMF). The experiment results revealed that at lower water cement ratio higher value of compressive strength was observed. It was also observed that the strength increases with curing period.

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Testing and Prediction of the Strength Development of Recycled-Aggregate Concrete with Large Particle Natural Aggregate

Materials ◽

10.3390/ma12121891 ◽

2019 ◽

Vol 12 (12) ◽

pp. 1891 ◽

Cited By ~ 4

Author(s):

Changyong Li ◽

Fei Wang ◽

Xiangsheng Deng ◽

Yizhuo Li ◽

Shunbo Zhao

Keyword(s):

Large Particle ◽

Coarse Aggregate ◽

Recycled Aggregate Concrete ◽

Time Dependent ◽

Recycled Aggregate ◽

Strength Development ◽

Aggregate Concrete ◽

Cement Ratio ◽

Water Cement Ratio ◽

Natural Aggregate

In this paper, a new recycled aggregate concrete (RAC) was produced with composite coarse aggregate and fine recycled aggregate. The composite coarse aggregate was mixed into continuous gradation by large particle natural aggregate with small particle recycled aggregate. To explore the time-dependent developments of the compressive strength and splitting tensile strength of this new RAC, 320 groups of cubic specimens were tested at different curing ages from 3 days to 360 days to measure the compressive and splitting tensile strengths. The amount of large particle natural aggregate varied from zero to 70% in mass of the total coarse aggregate. The water/cement ratio was taken as 0.60, 0.49, 0.41 and 0.36 to represent four strength grades of the RAC at about C20, C30, C40 and C50. Based on the tested results, the curves of the compressive and tensile strengths of the RAC that changed with curing age are plotted, which clearly exhibit that the amount of large particle natural aggregate had a rational range in different strength grades of the RAC which had better aging strength. When the RAC was no larger than C30 with a water/cement ratio of 0.60 and 0.49, the amount of large particle natural aggregate should be no more than 30%; when the RAC was no less than C40 with a water/cement ratio of 0.41 and 0.36, the amount of large particle natural aggregate should be no less than 50%. Along with the general prediction of the strength development of all the tested RAC, the optimal predictive formulas are proposed for the strength development of RAC with a rational amount of natural aggregate. Meanwhile, the strength developments of RAC with a rational amount of natural aggregate are assessed by the time-dependent models proposed by the ACI Committee 209 and CEB-FIP MC 2010.

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