Influence of Ground Slag on the Rheology of Mortar

2013 ◽  
Vol 438-439 ◽  
pp. 67-71
Author(s):  
Qian Qian Zhang ◽  
Jian Zhong Liu ◽  
Jia Ping Liu
Keyword(s):  
Film Thickness ◽  
Specific Surface ◽  
Yield Stress ◽  
Surface Area ◽  
Specific Surface Area ◽  
Water Film ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Water Film Thickness ◽  
Binder Ratio

The effects of ground slag with different specific surface area on the rheology of mortar at water-binder ratio of 0.25, 0.28 and 0.30 were investigated, and the combined effects of packing density and solid surface area on the rheology of mortar were evaluated in terms of the water film thickness. The results show that with the increasing of specific surface area of slag (220 m2/kg-784 m2/kg), plastic viscosity and yield stress decrease. The correlations of yield stress and plastic viscosity to the water film thickness are basically linear with high correlation R2 values. The action of the ground slag on the rheology of mortar can be characterized by water film thickness, and with the increasing of water film thickness the rheological parameters decrease.

scholarly journals Evolution of flow properties, plastic viscosity, and yield stress of alkali-activated fly ash/slag pastes

2020 ◽  
Vol 5 ◽  
pp. 141-149
Author(s):  
Mohammed Fouad Alnahhal ◽  
Taehwan Kim ◽  
Ailar Hajimohammadi
Keyword(s):  
Fly Ash ◽  
Yield Stress ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Time Intervals ◽  
Increasing Trend ◽  
Binder Ratio ◽  
Drastic Effect ◽  
Effect On Yield ◽  
Alkali Activated

The development of cementless concrete is attracting increasing attention in practice and research to reduce both greenhouse gas emissions and energy consumption of concrete. Alkali-activated materials (AAMs) are one of the viable alternatives to replace Portland cement due to their lower CO2 emissions. This study investigated the evolution of rheological parameters of alkali-activated fly ash/slag pastes as a function of time. Flowability and rheological measurements were carried out to determine the fluidity, plastic viscosity, and yield stress at different time intervals. The effects of the slag content, the concentration of SiO2 in the activator, and the solution/binder ratio were considered. Based on the results, the yield stress and plastic viscosity followed an increasing trend over time coinciding with a reduction in the paste fluidity. The plastic viscosity of AAM pastes was in the range of 1.3–9.5 Pa.s and 2.6–28.9 Pa.s after 5 min and 45 min of mixing, respectively. Given the same alkali activator, the higher content of slag the paste had, the higher yield stress the paste showed. In addition, this paper confirmed that the SiO2/Na2O ratio in the activator had no significant effect on yield stress, but a drastic effect of this ratio was found on the plastic viscosity of the paste.

scholarly journals A Study on the Relationships between Water Film Thickness, Fresh Properties, and Mechanical Properties of Cement Paste Containing Superfine Basalt Powder (SB)

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7592
Author(s):  
Hengrui Liu ◽  
Zhenghong Tian ◽  
Haoyue Fan
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Film Thickness ◽  
Cement Paste ◽  
Water Film ◽  
Mineral Admixtures ◽  
Rheological Parameters ◽  
Fresh Properties ◽  
Bleeding Rate ◽  
Water Film Thickness

In this paper, the effect of a newly developed superfine basalt powder (SB) on the fresh and mechanical properties of cement paste was studied. The concept of water film thickness (WFT) was cited to explain the influence of SB on fresh and mechanical properties and related mathematical model formulas were established. In addition, the relationship between the fresh properties and mechanical properties of paste was also explored. The results indicated that SB can improve the segregation resistance and cohesiveness. The maximum improvement rate relative to the control cement paste was 75.4% and 50.4%, respectively. The 5% SB and 10% SB reduced the fluidity in the range of 4.1–68.7% but increased the early and late compressive strength in the range of 1.2–25.7% compared to control cement paste under different water/cementitious materials (W/CM) ratios. However, the influence of 20% SB on fluidity and compressive strength was opposite to the above behavior, and the increase rate and decrease rate were 1.8–11.8% and 1.1–13.9% respectively. The WFT was the most important factor that determined the compressive strength, rheological parameters, and flow parameters of paste containing SB, while the substitute content of SB and WFT together determined the bleeding rate and cohesiveness. Among them, the correlation between bleeding rate and WFT increased with time. The empirical mathematical models between WFT, fresh properties, and compressive strength were established and verified by other mineral admixtures, which were successfully extended and applied to the entire field of cement-based materials

scholarly journals Effect of Silica Fume on the Rheological Properties of Cement Paste with Ultra-Low Water Binder Ratio

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 554
Author(s):  
Juan He ◽  
Congmi Cheng ◽  
Xiaofen Zhu ◽  
Xiaosen Li
Keyword(s):  
Hysteresis Loop ◽  
Rheological Properties ◽  
Yield Stress ◽  
Silica Fume ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Loop Area ◽  
Binder Ratio ◽  
Hysteresis Loop Area ◽  
Water Binder Ratio

The effect of silica fume on the rheological properties of a cement–silica fume–high range water reducer–water mixture with ultra-low water binder ratio (CSHWM) was studied. The results indicate that the W/B ratio and silica fume content have different effects on the rheological parameters, including the yield stress, plastic viscosity, and hysteresis loop area. The shear-thickening influence of CSHWM decreased with the increased silica fume content. When the silica fume content increased from 0% to 35%, the mixture with W/B ratio of 0.19 and 0.23 changed from a dilatant fluid to a Newtonian fluid, and then to a pseudoplastic fluid. When the silica fume content was less than 15%, the yield stress was close to 0. With the increase of silica fume content, the yield stress increased rapidly. The plastic viscosity and hysteresis loop area decreased slightly with the addition of a small amount of silica fume, but increased significantly with the continuous increase of silica fume. Compared with the Bingham and modified Bingham models, the Herschel–Buckley model is more applicable for this CSHWM.

Experimental Research on Rheological Properties of Cemented Mortar in Tail Void Grouting of Shield Tunnel

2011 ◽  
Vol 261-263 ◽  
pp. 1201-1205 ◽  
Author(s):  
Xiao Hui Yuan ◽  
Yue Wang Han
Keyword(s):  
Rheological Properties ◽  
Flow Pattern ◽  
Yield Stress ◽  
Plastic Viscosity ◽  
Rheological Parameters ◽  
Shear Yield Stress ◽  
Shear Yield ◽  
Binder Ratio ◽  
Water Ratio ◽  
Water Binder Ratio

Grout flow pattern and rheological parameters determine grouting pressure transfer process in annular tail void and filling rate for shield tail void. However, cemented mortar is a mixture of cement, fly ash, sand, bentonite and water, which lead to grout rheological properties and rheological parameters are difficultly determined. Based on orthogonal experimental design method, grout rheological properties were tested by rotational viscometer. Utilizing variance and poly-nonlinear regression analysis, the qualitative and quantitative relationships between mix ratios and rheological parameters were obtained respectively. It is shown that cemented mortar flow pattern commonly agree with Bingham fluid type, and plastic viscosity varies between 1 and 4Pa•s, and shear yield stress varies between 10 to 40Pa respectively. Water-binder ratio and bentonite-water ratio are key influencing factors for grout rheological parameters. With the water-binder ratio increasing and bentonite-water ratio decreasing, plastic viscosity and shear yield stress present reducing tendency.

scholarly journals ASSESSMENT OF THE IMPACT OF MODIFIER AND FILLER ON THE RHEOLOGICAL AND PHYSICAL AND MECHANICAL PROPERTIES OF PLASTER SOLUTIONS

2021 ◽  
pp. 105-113
Author(s):  
S.V. Savchenko ◽  
◽  
N.R. Antoniuk ◽  
V.V. Bachynckyi ◽  
◽  
...  
Keyword(s):  
Specific Surface ◽  
Rheological Properties ◽  
Surface Area ◽  
Specific Surface Area ◽  
Physical And Mechanical Properties ◽  
Sio2 Content ◽  
Rheological Parameters ◽  
Determining Factors ◽  
The Impact ◽  
Selection Of

Abstract. The possibility of using microsilica as a filler for cement plaster mortars was analyzed. As a result of the analysis of reference data, the features of the hydration of cement with microsilica were determined. In the experiments, the rheological characteristics of cement slurries containing microsilica with different contents of amorphous silica and specific surface area were studied. One of the most important objects of studying the effect of microsilica and superplasticizer additives on the properties of plaster solutions was optimization due to the optimal selection of the concentrations of additives, the rheological properties of mixtures and their ratio with technological and operational factors. For the analysis and optimization, the quantitative ratio between the indicators of the structure and properties of plaster solutions and their determining factors, the formulations and technologies were obtained in the form of experimental-statistical models calculated using the COMPEX system. Based on the results of measurements of the rheological properties of cement solutions containing silica fume with the highest specific surface area and SiO2 content, complete rheological curves "strain rate – stress" were constructed and models of the main rheological parameters were calculated. To analyze the possibility of regulating the properties of cement systems with a superplasticizer, depending on the grain and chemical composition of the ultradispersed filler, multicomponent tetrahedral diagrams, which were combined with the concentration space of DSP -DМC in the "mixture – technology – properties" models were used. A specially synthesized saturated plan of 21 points has been implemented. Models were obtained in the form of reduced polynomials for different properties of cement-sand mortars (mobility and compressive strength after 1, 3, 9, 28 and 81 days of hardening in normal humidity conditions). Using a generalizing indicator, the sensitivity of the system to fluctuations in the fractional composition and SiO2 content was estimated.

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