Effect of polypropylene fiber content and fiber length on the saturated hydraulic conductivity of hydrating cemented paste backfill

2020 ◽  
Vol 262 ◽  
pp. 120854
Author(s):  
Sirisha Chakilam ◽  
Liang Cui
Keyword(s):  
Hydraulic Conductivity ◽  
Fiber Length ◽  
Polypropylene Fiber ◽  
Saturated Hydraulic Conductivity ◽  
Fiber Content ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Saturated hydraulic conductivity of cemented paste backfill

2009 ◽  
Vol 22 (15) ◽  
pp. 1307-1317 ◽  
Author(s):  
M. Fall ◽  
D. Adrien ◽  
J.C. Célestin ◽  
M. Pokharel ◽  
M. Touré
Keyword(s):  
Hydraulic Conductivity ◽  
Saturated Hydraulic Conductivity ◽  
Cemented Paste Backfill ◽  
Paste Backfill

scholarly journals Insight into Saturated Hydraulic Conductivity of Cemented Paste Backfill Containing Polycarboxylate Ether-Based Superplasticizer

Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
Sada Haruna ◽  
Mamadou Fall
Keyword(s):  
Hydraulic Conductivity ◽  
Environmental Performance ◽  
Mining Industry ◽  
Design Criterion ◽  
Saturated Hydraulic Conductivity ◽  
Curing Temperature ◽  
Partial Replacement ◽  
Cemented Paste Backfill ◽  
Curing Conditions ◽  
Paste Backfill

Recycling of tailings in the form of cemented paste backfill (CPB) is a widely adopted practice in the mining industry. Environmental performance is an important design criterion of CPB structures. This environmental performance of CPB is strongly influenced by its saturated hydraulic conductivity (permeability). Superplasticizers are usually added to improve flowability, but there is a limited understanding of their influence on the hydraulic properties of the CPB. This paper presents new experimental results on the variations of the hydraulic conductivity of CPB containing polycarboxylate-based superplasticizer with different compositions and curing conditions. It is found that the hydraulic conductivity of the CPB decreases with the addition of superplasticizer, which is beneficial to its environmental performance. The reduction is largely attributable to the influence of the ether-based superplasticizer on particles mobility and cement hydration. Moreover, both curing temperature and time have correlations with the hydraulic conductivity of CPB containing superplasticizer. In addition, the presence of sulfate and partial replacement of PCI with blast furnace slag reduces the hydraulic conductivity. The variations are mainly due to the changes in the pore structure of the CPB. The new results discussed in this manuscript will contribute to the design of more environmental-friendly CPBs, which is essential for sustainable mining.

MONOLITH COLUMNS FOR STUDYING ORGANIC SOIL PROFILES

1986 ◽  
Vol 66 (4) ◽  
pp. 737-742
Author(s):  
J. A. MILLETTE ◽  
R. S. BROUGHTON
Keyword(s):  
Hydraulic Conductivity ◽  
Physical Properties ◽  
Bulk Density ◽  
Organic Soil ◽  
Saturated Hydraulic Conductivity ◽  
Fiber Content ◽  
Organic Soils ◽  
Soil Profiles ◽  
Sampling Procedures ◽  
Monolith Columns

Monolith column construction and sampling procedures were described for organic soil profiles and used to measure the variation with depth of saturated hydraulic conductivity, bulk density and fiber content. The top 0.30 m of the organic soil was more permeable, had a greater bulk density and had a greater fiber content than the soil layer between 0.60 and 0.90 m from the soil surface. These columns can be used for correlations studies between physical properties and studies of the dynamic nature of the physical properties of organic soils. Key words: Saturated hydraulic conductivity, bulk density, fiber content, organic soil, monolith columns

scholarly journals Impermeability Durability of SCC Reinforced with Fibrillated Polypropylene Fiber

2015 ◽  
Vol 9 (1) ◽  
pp. 159-166
Author(s):  
X.B. He ◽  
Y. Li ◽  
Q. Shen
Keyword(s):  
Volume Content ◽  
Fiber Length ◽  
Slenderness Ratio ◽  
Polypropylene Fiber ◽  
Total Porosity ◽  
Fiber Content ◽  
Fiber Volume ◽  
Flexural Tensile Strength ◽  
Mix Proportion ◽  
Relative Water

The paper studied the influences of the volume content and slenderness ratio of fibrillated polypropylene fiber on the impermeability durability of self-consolidating concrete (SCC) reinforced with the fibrillated polypropylene fiber, and proposed to use the modified relative permeability coefficient method to evaluate the water-resistant properties of SCC reinforced with the fiber. Also, the influence mechanism of the fiber on the permeability of the concrete has been analyzed according to the mercury injection test, scanning electronic microscope (SEM) observation and the basic principles of fracture mechanics. Results showed that: 1) the total porosity of SCC gradually increased with the increase in the fiber content; 2) the harmful porosity of SCC decreased firstly and then increased with the increase in the fiber content, while the harmful porosity increased with the increase in the fiber length; 3) when the reference mix proportion of SCC was kept constant, the fiber volume content was not more than 0.10 %, and the appropriate fiber length ranged from 12 to 15mm; 4) when the volume content is no more than 0.15%, the hardened SCC reinforced with fibrillated polypropylene fiber possessed good water impermeability gradation (＞P12); the splitting strength and flexural tensile strength of the hardened SCC reinforced with fibrillated polypropylene fiber increased with the addition of the fiber content; the relative water penetration coefficient of the hardened SCC reinforced with fibrillated polypropylene fiber decreased with the addition of the fiber content firstly and then increased; the Coulomb value first increased smoothly (the maximum Coulomb value is less than 2000C, and low according to JTJ/T 193-2009 and ASTM C 1202), and then increased sharply.

scholarly journals Stability Analysis of Soil Embankment Slope Reinforced with Polypropylene Fiber under Freeze-Thaw Cycles

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yafeng Gong ◽  
Yulong He ◽  
Chunpeng Han ◽  
Yangfan Shen ◽  
Guojin Tan
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Finite Element Model ◽  
Fiber Length ◽  
Polypropylene Fiber ◽  
Element Model ◽  
Fiber Content ◽  
Freeze Thaw ◽  
Embankment Slope ◽  
The Finite Element Model

Polypropylene fiber is a common soil reinforcement material which is used to reinforce a common clay in northeast China. Numerical analysis method was performed to investigate the effect of polypropylene fibers on stability of embankment slope subjected to freeze-thaw cycles. The orthogonal experiments of three factors (freeze-thaw cycle, fiber content, and fiber length) and three levels were carried out, and the corresponding nine groups of specimens were made, whose shear strength parameters (internal friction angle and bond force) were measured by direct shear test. Then, the experimental results were analyzed by analysis of variance and range analysis so that the optimum fiber content and fiber length can be determined. The finite element model of typical high-fill soil slope of freeway in northeast China was established whose basic material parameters were taken as the parameters of shear strength of different freeze-thaw cycles under the optimum fiber content and fiber length. The concept of shear strength reduction was introduced into the finite element model, and the convergence of the finite element model was taken as the judging criterion of slope stability. Thus, stability analysis of soil embankment slope reinforced with polypropylene fiber under freeze-thaw cycles was realized. The results show that the addition of fibers improves the cohesion under the action of freeze-thaw cycles, and the internal friction angle is improved in the case of freezing and thawing. This phenomenon leads to the improvement of the stability of the embankment slope in a freeze-thaw cycle. The improvement is particularly noticeable in the case, and this improvement effect decreases as the number of freeze-thaw cycles increases.

Experimental study on the strength of silty soft soil in beach with polypropylene fiber reinforcement

2020 ◽  
pp. 10-17
Author(s):  
Qi Daozheng ◽  
Gu Cong ◽  
Fu Jiajia ◽  
Wang Yao
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Shear Strength ◽  
Internal Friction ◽  
Unconfined Compressive Strength ◽  
Fiber Length ◽  
Soft Soil ◽  
Polypropylene Fiber ◽  
Fiber Reinforcement ◽  
Fiber Content

The effects of polypropylene fiber reinforcement on shear strength and unconfined compressive strength of silty soft soil in tidal flats were studied. Through shear test and unconfined compression test, Experimental study was conducted on silty soft soil of allene fiber reinforced beach with 0~0.6% different mass content and 3 ~18m different length. The failure process and mechanism of fiber reinforced soil samples were also discussed. The test results show that: Shear strength (cohesion and internal friction Angle) and unconfined compressive strength increased rapidly in the early stage with the increase of fiber content, and gradually decreased after reaching the peak at a certain content. In this test, the optimal fiber length corresponding to shear strength is 9mm. When the content is less than 0.6%, the optimal content of cohesion is about 0.2%, and the optimal content corresponding to the Angle of internal friction is between 0.2% and 0.3%. Within the range of 18mm fiber length in the experimental study, unconfined compressive strength increased with the increase of fiber length, and the optimal fiber content corresponding to unconfined compressive strength was 0.2%. The main effects of polypropylene fiber reinforcement on soil cohesion and unconfined compressive strength are not obvious.

scholarly journals Effect of Rice Straw on Tensile Properties of Tailings Cemented Paste Backfill

2022 ◽  
Vol 12 (1) ◽  
pp. 526
Author(s):  
Zeyu Li ◽  
Xiuzhi Shi ◽  
Xin Chen
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Rice Straw ◽  
Orthogonal Experiment ◽  
Fiber Content ◽  
Hydration Reaction ◽  
Percentage Increase ◽  
Cemented Paste Backfill ◽  
Curing Period ◽  
Paste Backfill

It is important and difficult to improve the tensile strength of backfill material to ensure the stability of goafs. In this study, rice straw (RS) in fiber form is used to improve the tensile properties of cemented paste backfill (CPB). An orthogonal experiment was designed, Brazilian indirect tensile strength tests were conducted to test the tensile performance of RS fiber-reinforced cemented paste backfill (RSCPB) under different fiber content (1, 2, 3 kg/m3) and fiber length (0.8~1, 1~3, 3~5 cm), and the microstructure of RSCPB was analyzed with scanning electron microscopy (SEM). The results showed that, compared with the conventional cemented paste backfill (CCPB), the increase in tensile strength of RSCPB ranged from 115.38% to 300.00% at 3 days curing age, 40.91% to 346.15% at 7 days, and −38.10% to 28.00% at 28 days., and the strain was slightly reduced during the curing period. The tensile strength, strain, and percentage increase of the RSCPB compared to the CCBP did not show a monotonic pattern of variation with the RS fiber content and length during the curing period. The RSCPB samples fractured under peak stress, showing obvious brittle failure. In addition, sulfate generated from S2− in the tailings inhibits the hydration reaction, and generates swelling products that form weak structural surfaces, which, in turn, lead to a 28-day tensile strength and strain of RSCPB lower than those at 7 days.

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