scholarly journals COMPARISON OF THE BEHAVIOR OF FIBER AND MESH REINFORCED SOILS

2017 ◽  
Vol 8 (2) ◽  
pp. 82-88
Author(s):  
Y. C. Fung ◽  
Shenbaga. R. Kaniraj

Soft soil does not have good soil properties and is not suitable for constructing pavement structures as shear strength is required to resist the shear stress developed by traffic loading. To increase shear strength in this study, lime is used as the soil stabilizing agent and fiber and mesh are used as the soil reinforcement materials. The proper amount of lime added to soil will increase the shear strength as the lime-treated soil will decrease moisture susceptibility and migration. Shear strength of the lime-treated soil can be further improved by adding reinforcement materials such as fiber and mesh. The reinforcement materials will interlock with groups of particles and provide tensile strength to the soil matrix. The type of soil used in this study is high plasticity elastic silt with sand which is classified using the Unified Soil Classification System (USCS). Quicklime (calcium oxide) is used in this study at the minimum amount required for stabilizing the soil, which is 9%. The amount of fiber and mesh added to the soil sample is 0.5% of the dry weight of the soil used. Cylindrical samples were prepared with a moisture content of 22% (OMC) for untreated soil and 21% (OMC) for lime-treated soil samples. The lime-treated soil samples were cured for 7, 14, 28, 56, 90 and 120 days. Unconfined compression tests were conducted to determine unconfined compressive strength (UCS) and stress-strain characteristics. The unconfined compressive strength of the lime-treated samples increased as curing period increased but the failure strain decreased. The UCS and failure strain for reinforced lime-treated soil samples are higher than the unreinforced lime-treated soil samples.

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Son Bui Truong ◽  
Nu Nguyen Thi ◽  
Duong Nguyen Thanh

Soft soil is widely distributed in Vietnam, especially in the coastal area. In engineering practice, soft soil cannot be used to build any construction and needs to be improved or treated before building construction. In addition, Vietnam has many pig-iron or thermal power plants, which annually produce a huge amount of granulated blast furnace slag (GBFS). Thus, the use of this material for soft soil improvement needs to be considered. This paper presents experimental results on the unconfined compressive strength (UCS) of three Vietnam’s soft soils treated with Portland cement and Portland cement with ground granulated blast furnace slag (GGBFS). Binder dosage used in this study is 250, 300, and 350 kg/m3 with the three different water/cement ratios of 0.8, 0.9, and 1.0, respectively. The research results showed that the UCS of soil-cement mixtures depends on soil type, water/cement ratio, cement type, and binder content. Accordingly, the unconfined compressive strength increased with the increase of binder contents, the decrease of the natural water content of soft soil, water/cement ratios, and clay content. The highest value of UCS of treated soils was found for the soil at Site II with the Portland cement content, cement GGBFS, and water/cement ratio of 873 kg/m3, 2355 kg/m3, and 0.8, respectively. Besides, for all the three soils and two binder types, the water/cement ratio of 0.8 was found to be suitable to reach the highest UCS values of treated soil. The research results also showed that the UCS of treated soil with cement GGBFS was higher than that of treated soil with Portland cement. This indicated the effectiveness of the use of Portland cement with GGBFS in soft soil improvement. There is great potential for reducing the environmental problems regarding the waste materials from pig-iron plants in Vietnam and the construction cost as well.


2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Qian Guo ◽  
Mingli Wei ◽  
Haochen Xue ◽  
Changhui Gao ◽  
Guangyin Du

This paper focuses on the strength development and pore structure evolution of high-plasticity clay mixtures treated with metakaolin- (MK-) blended ordinary Portland cement (OPC). The unconfined compressive strength (fcu) of treated soil mixtures is measured to study the effect of MK replacement. The microstructural study is carried out by mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results showed that the MK replacement led to the decrease of unconfined compressive strength of OPC-treated soil mixture cured for 28 days, but the influence on 7 days strength was negligible. However, the MK addition also enhanced the unconfined compressive strength significantly. The MK addition provided more cementitious products by secondary hydration and pozzolanic reaction, which would give rise to a notable filling effect by turning the large pores (1 to 10 μm) into smaller ones (0.1 to 1 μm). However, the MK replacement led to a decrease of cementitious products due to the lack of calcium hydroxide (CH) in soil mixture, and thus the effect on pore structure refinement was reduced. Nevertheless, the presence of MK enhanced the unconfined compressive strength cured for 7 days, due to the high reactivity of MK with CH.


2018 ◽  
Vol 7 (4) ◽  
pp. 75
Author(s):  
Abdulrahman Aldaood ◽  
Amina Khalil ◽  
Marwen Bouasker ◽  
Muzahim Al-Mukhtar

This research study was carried out to investigate the impact of freeze-thaw cycles on the mechanical and the mineralogical properties of lime treated fine-grained soil. The unconfined compressive strength, wave velocity, volume change, water content, pH and electrical conductivity values were determined during freeze-thaw cycles. Furthermore, Mercury porosimetry and X-ray diffraction tests were carry out to determine changes at microscopic level. The soil used in this study was taken at a site near Jossigny region in eastern part of Paris–France. The soil samples were treated with optimum lime percent 3% depending on the pH method, then cured for 28 days at 20 °C. The soil samples were subjected to 12 cycles of freeze-thaw following ASTM procedure.    The result referred that, natural soil exhibit no strength resistance against freeze-thaw cycles and failed during the first hours of freeze-thaw cycles. Analyses indicated that freeze-thaw cycles reduce the unconfined compressive strength of all the tested samples. Moreover, water content during the applied cycles increases and induces significant volume changes. During freeze-thaw cycles, the cracks propagation which caused by the formation of ice lenses in the pores of lime treated soil samples were consider to have significant. The changes in the micro-structural and mineralogical properties reduce the durability  of the lime treated soil samples when subjected to freeze-thaw cycles.


2020 ◽  
pp. 10-17
Author(s):  
Qi Daozheng ◽  
Gu Cong ◽  
Fu Jiajia ◽  
Wang Yao

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.


2018 ◽  
Vol 53 ◽  
pp. 04021
Author(s):  
SHAO Yong ◽  
LIU Xiao-li ◽  
ZHU Jin-jun

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.


2020 ◽  
Vol 998 ◽  
pp. 323-328
Author(s):  
Achmad Bakri Muhiddin ◽  
Marthen M. Tangkeallo

In remote areas, most roads still use pavements that are very sensitive to climate change, especially those using clay pavements with high plasticity. In addition to the issue of cost, the difficulty of obtaining a proper source of material is another problem that has led to soaring prices for materials. In this regard, a study was conducted using local materials, namely zeolite as a stabilizing material added with waterglass as activating agent. The research began with samples of laterite soil and natural zeolite for XRD test (microstructure testing), and then testing for laterite soil’s index properties and engineering properties, namely Unconfined Compressive Strength and CBR value. The purpose of the test is to determine the correlation between the Unconfined Compressive Strength (UCS) and the soil bearing capacity (CBR) caused by adding zeolite as stabilizer material and waterglass as activator with increasing curing time. Laterite soils contain a brownish red iron oxide. The stabilizing material zeolite contains a crystalline mineral of alumina silicate SiO2. While waterglass composed of sodium meta silicate. Stabilization carried out by mixing 4%, 8%, 12%, 16%, and 20% of zeolite with addition of 2% waterglass, percentage was measured based on soil dry weight. Specimens were tested at curing time of 0, 7, 14, and 28 days. The test result shows increasing UCS and CBR values with increasing percentage of zeolite. At mix of 20% zeolite and 2% waterglass, the unconfined compressive strength reaches 23.54 kg/cm2 with CBR value 58% at 28 days of curing time.


2020 ◽  
Vol 998 ◽  
pp. 329-334
Author(s):  
Maraden Panjaitan ◽  
Lawalenna Samang ◽  
Achmad Bakri Muhiddin ◽  
Tri Harianto

The main problem in infrastructure development at the soft clay was its bearing capacity therefore it needs to be improved. In this research, the improvement method was carried out by modeling in small scale of preloading and heat induction combination. Location of soft clay sampling was in Takalar, Indonesia. The purpose of this study was to investigate the change of the shear strength of soft soil corresponding with heat induction at the radial zone. The shear strength was obtained by vane shear test and compressive strength from unconfined compressive test (UCT). The heat applied ranging from 100o C, 200o C, 300o C, and 400o C with static preloading load 0.20 kg/cm2. The strengths of the soil in radial zones have been tested at R0, R1, and R2. At lowest temperature 100° at R0 the compressive strength was 0.203 kg/cm2, at highest temperature 400° at R0 the compressive strength 0.467 kg/cm2, there was a significant increasing of compressive strength value with the change of temperature. At the highest temperature 4000 the shear strength from vane shear tests resulting at R0 0.240 kg/cm2, R1 of 0.128 kg/cm2, R2 of 0.077 kg/cm2. At the lowest temperature of 100o C shows R0 at 0.116 kg/cm2, R1 at 0.070 kg/cm2, R3 of 0.046 kg/cm2. The results show a tendency of declining strength value as the soil farther away from center of heat induction. The experimental result from this model produces strength that can be used as a parameter of the foundation model on soft soil.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Panbarasi Govindasamy ◽  
Mohd Raihan Taha ◽  
Jamal Alsharef ◽  
Kowstubaa Ramalingam

This paper presents the improvement of the unconfined compressive strength (UCS) of soil by mixing different percentages of nanolime and 5% lime with soil. The UCS of treated soil increased significantly over curing time with increasing percentage of nanolime. The optimum results were reached at only 0.5% nanolime admixtures which were much higher than 5% lime admixture. This may be due to higher ability of nanolime to flocculate and agglomerate the soil particles compared with the lime. In addition, the lime could fill only the micropores while nanolime could fill the micro- and nanopores as well. The strength gain is inversely proportional to the remolded moisture content and curing period. However, when the content of nanolime used is larger than 0.5%, nanolime particles are not uniformly dispersed. Therefore, a weak area in the form of voids is created, consequently the homogeneous hydrated microstructure cannot be formed, and finally the strength will decrease.


2011 ◽  
Vol 250-253 ◽  
pp. 788-794
Author(s):  
Shu Lin Zhan ◽  
Shu Sen Gao ◽  
Jun Ying Lai

In order to study the influence of modified polypropylene (PP) fiber on the physical and mechanical properties of curing sludge, the same amount of cement and different content of polypropylene fiber were mixed into the sludge. Unconfined compressive strength tests, water content tests and shear strength tests were carried out on different specimens with different curing time. The results show that the sludge curing effect is markedly improved by the addition of the polypropylene fiber. As to the curing sludge with the same curing time, when the content of the polypropylene fiber increases, the unconfined compressive strength and the cohesive strength greatly increase, and the internal frictional angle decreases.


2011 ◽  
Vol 255-260 ◽  
pp. 4012-4016
Author(s):  
Jun Qing Ma ◽  
You Xi Wang

This paper studies relationship between soil-cement parameters and unconfined compressive strength. The research in tensile strength and deformation modulus of soil-cement is an important basis for soil-cement failure mechanism and intensity theory. They also impact cracks, deformation and durability of cement-soil structure. Shear strength and deformation of soil-cement is important to the destruction analysis and finite element calculations. Therefore it needs to study on tensile strength, shear strength and deformation modulus of soil-cement. Based on previous experiments, the relationship of tensile strength, shear strength, deformation modulus and unconfined compressive strength of soil-cement are quantitatively studied.


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