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Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 375
Author(s):  
Syafiadi Rizki Abdila ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Romisuhani Ahmad ◽  
Dumitru Doru Burduhos Nergis ◽  
Shayfull Zamree Abd Rahim ◽  
...  

Geopolymers, or also known as alkali-activated binders, have recently emerged as a viable alternative to conventional binders (cement) for soil stabilization. Geopolymers employ alkaline activation of industrial waste to create cementitious products inside treated soils, increasing the clayey soils’ mechanical and physical qualities. This paper aims to review the utilization of fly ash and ground granulated blast furnace slag (GGBFS)-based geopolymers for soil stabilization by enhancing strength. Previous research only used one type of precursor: fly ash or GGBFS, but the strength value obtained did not meet the ASTM D 4609 (<0.8 Mpa) standard required for soil-stabilizing criteria of road construction applications. This current research focused on the combination of two types of precursors, which are fly ash and GGBFS. The findings of an unconfined compressive strength (UCS) test on stabilized soil samples were discussed. Finally, the paper concludes that GGBFS and fly-ash-based geo-polymers for soil stabilization techniques can be successfully used as a binder for soil stabilization. However, additional research is required to meet the requirement of ASTM D 4609 standard in road construction applications, particularly in subgrade layers.


2021 ◽  
Author(s):  
Rasoul Alipour

Abstract Existing problematic sub-layers in mixing technologies are a challenge, and for the first time, the effects of salt sub-layers in mass mixing technology have been investigated in this study for sandy salt in the southwest of Iran. This paper discusses the influence of adding various cement contents, Aw, and imposing different preloading values on the salty sand soil. First, salt and sand samples were dried, then, 90 % sand was mixed with 10% salt. After that, 30 % water was mixed thoroughly with the mixture of salty sand to obtain slurries. Cement slurry at a water-cement ratio (w/c) of 0.6 was then added to the sample and thoroughly mixed. The amount of cement in a slurry form that was added to the salty soil was 2, 4, 6, 8, and 10% by mass of dry soil. Each treated soil preloaded by 0, 9, and 45 kPa. After 120 days, the unconfined compressive strength of the sample was determined. Furthermore, by Scanning Electronic Microscope, SEM, the microstructures of treated samples were analyzed. At the end Unconfined Compression Strength, UCS, test results normalized to the non-preloaded treated soil. By increasing cement content, the effect of preloading in increasing UCS will decrease. In the SEM images for Aw=2%, the effect of preloading indicates porous shape for non-preloaded samples. Vice versa by Aw=8%, porous shape in the SEM images will disappear. In the end, treatability studies of pure salt in the thick layer have been investigated.


2021 ◽  
Vol 411 ◽  
pp. 109-120
Author(s):  
Siti Rozana Romali ◽  
Norazzlina M. Sa’don ◽  
Abdul Razak Abdul Karim

High content of organic matter and fibre within peat results in a high degree of porosity; causing peat to have low bearing capacity. This study focuses on the application of nylon fibre as reinforcing material with fly ash as the chemical stabilizer to enhance the strength of the peat. The standard proctor tests were conducted to obtain the optimum moisture content (OMC) for all samples in which these OMC is then used for sample preparation of both the Unconfined Compressive Strength (UCS) tests and the California Bearing Ratio (CBR) tests. Samples for this study were categorized into control samples and modified samples for comparison purposes. Additives that were being used in this study are 5% cement, 5% nylon fibre and 10%, 15%, and 20% fly ash. For UCS test, the samples were cured for 7, 14, 28 and 56 days, whereas only 7 days of curing for CBR test. Throughout the study, improvements of strength were observed where sample added with 5% cement, 5% nylon fibre and 10% fly ash recorded the highest compressive strength value, of 123.71 kN/m2. As for CBR test, all samples exceeded the minimum requirement of 12% CBR value for subgrade design recommended by JKR Malaysia with the highest CBR value obtained from samples added with 5% cement and 10% fly ash. The CBR values were 43.85% and 43.70% for unsoaked and soaked condition, respectively.


2021 ◽  
Vol 411 ◽  
pp. 121-133
Author(s):  
Nur Amalina Hilwane ◽  
Norazzlina M. Sa’don ◽  
Abdul Razak Abdul Karim

This paper presents the peat ground improvement techniques using waste-tire as a fibre reinforced material. In this study, two sizes of the waste-tire are chosen, which are 0.05 mm and 1-3 mm, respectively. The collected peat is classified as Sapric peat with the degree of decomposition of H7 based on von Post classification with high moisture content of 400% was recorded. The Sapric peat is treated with the waste-tire at designated percentages of 5%, 10% and 15% with the addition of 5% of cement acting as a binder. The untreated and treated peat without and with cement content are compacted at the optimum moisture content for both the Unconfined Compressive Strength (UCS) test and Direct Shear Box Test. The specimens were air-cured for 7, 28, 56, and 90 days. Hypothetically, higher percentages of rubber improve the shear stress value of the treated peat. According to the results the finer size (0.05mm) of the tire produces a higher shear stress, which may due the finer sizes of the waste-tire filled the void between the soil particles. Further, from the 90 days of curing UCS results, there is a significant increase in compressive strength with the increase percentage of the waste-tire peat mixed samples. In summary, soil stabilized by the scrap-tire is believed to decrease the optimum moisture content and the maximum dry densities, but it helps in increasing the unconfined compressive strength value. Stabilizing by using the tire wastes not only increasing the strength of the soil, but it also helps in reducing the disposal problems.


2021 ◽  
Author(s):  
Tatiana Durmeková ◽  
Martin Bednarik ◽  
Petra Dikejová ◽  
Renáta Adamcová

Abstract The most significant factors affecting the results of Uniaxial Compressive Strength (UCS) test are the size, slenderness ratio h/d (ratio of height to diameter), and the shape of the rock specimen. The proposed experimental study shows the variable impact of these parameters on UCS values by implementing several lithological types. Standard strength tests were performed on four lithological types: granodiorite, limestone, sandstone and andesite. Cylindric and cube-shaped test specimens of different sizes were prepared from each rock. Cylindric specimens with diameter 20 mm, 35 mm, 50 mm and 70 mm with height to diameter ratio of 1:1 and 2:1, and cubic and prismatic specimens with an edge dimension of 50 mm were tested and analyzed. Obtained results of strength tests confirmed a high variability of current research opinions on how the size and shape of specimens influence the strength values of rocks. The study revealed the impossibility of conclusive correlations between the UCS and specimens to be generally applicable for all lithological types. Of the observed effects on the strength, the aspect of the specimen slenderness ratio was the most pronounced on all studied rocks.


2021 ◽  
Vol 2 (4) ◽  
pp. 1-7
Author(s):  
Damilola A. Ogundare

The need to improve the strength and durability of subgrade soil in recent times has become imperative using stabilizing materials that can be sourced locally at no/or very low cost in other to reach their design life span before a major repair is required. This necessitates the improvement that could be achieved by stabilizing subgrade soil along Ede-Abeere road in Ede, Osun State with the Waste Plastic Bottle (WPB). The soil samples were collected at 1m depth at different portions along the road and stabilized with varying percentages of WPB. Laboratory tests conducted were sieve analysis, natural moisture content, specific gravity, Atterberg limit, compaction, California Bearing Ratio (CBR), and Unconfined Compressive Strength (UCS) Test. The CBR of the stabilized soil ranges from 1.28% to 12.20% with 2.5% WPB having the highest CBR value of 12.20% meeting the recommended value for unsoaked CBR of subgrade soils. However, the statistical model reliably adjudged that there is a significant relationship between the CBR values of subgrade soil-WPB mixture obtained. Thus, it is recommended that WPB at 2.5% can serve as a stabilizing material as it increases the CBR of the subgrade soil and as an effective method of disposing of WPB.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Haijun Wang ◽  
Xiaogang Sun ◽  
Jianwen Wang ◽  
Yun Duan ◽  
Changsuo Zhang ◽  
...  

In order to quantitatively study the influence of tailings fine content on the properties of cemented paste backfill (CPB) and further understand the mechanism of tailings fine content acting, the concept of packing density was introduced in this study. The packing density of each tailings sample was measured by the wet packing method after the samples with various fine contents were prepared. Moreover, CPBs with different tailings fine contents were tested by the mini slump test, rheological test, uniaxial compressive strength (UCS) test, and mercury intrusion porosimetry test. The results demonstrated that the flow spread and UCS both increase first and then decrease with the increase of tailings fine content, while the yield stress shows an opposite trend. The fine content of tailings affects the flowability of fresh CPB mainly through the packing density. When the fine content is high, the influence of the specific surface area of tailings cannot be ignored. The packing density is an important factor affecting the strength of CPB, and there is an obvious linear relationship between the packing density and UCS. The pore structure of CPB samples with different tailing fine contents is significantly different, and the macroscopic packing density changes the strength of CPB by affecting the microscopic pores.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2765
Author(s):  
Hua Yuan ◽  
Guanzhou Ren ◽  
Kang Liu ◽  
Zhiliang Zhao

Enzyme-induced calcium carbonate precipitation (EICP) technology can improve the strength of treated soil. But it also leads to remarkable brittleness of the soil. This study used polyvinyl alcohol (PVA) fiber combined with EICP to solidify sand. Through the unconfined compressive strength (UCS) test, the effect of PVA fiber incorporation on the mechanical properties of EICP-solidified sand was investigated; the distribution of CaCO3 in the sample and the microstructure of fiber-reinforced EICP-treated sand were explored through the calcium carbonate content (CCC) test and microscopic experiment. Compared with the sand treated by EICP, the strength and stiffness of the sand reinforced by the fiber combined with EICP were greatly improved, and the ductility was also improved to a certain extent. However, the increase of CCC was extremely weak, and the inhomogeneity of CaCO3 distribution was enlarged; the influence of fiber length on the UCS and CCC of the treated sand was greater than that of the fiber content. The improvement of EICP-solidified sand by PVA fiber was mainly due to the formation of a “fiber–CaCO3–sand” spatial structure system through fiber bridging, not the increase of CCC.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Kangli Cheng ◽  
Bingbing Tu ◽  
Lang Liu ◽  
Bo Zhang ◽  
Huafu Qiu

In order to consider the influence of mesoscopic characteristics of materials on the constitutive model of cemented paste backfill (CPB), the uniaxial compression variables and the damage constitutive model, considering the influence of porosity and pore size of filling materials, were derived based on the strain equivalence principle and Weibull probability distribution function. The nuclear magnetic resonance (NMR) tests and unconfined compression strength (UCS) tests were carried out on 8 groups of CPB specimens with different slurry concentrations and cement-tailings ratios. Then, the expression of damage strengthening coefficient is determined, and the stress-strain curves measured by the theoretical model were compared with the experimental ones. The results show that the uniaxial compression constitutive model proposed is in good agreement with UCS test results and can effectively describe the damage evolution law and the development process of stress-strain curve of CPB under uniaxial compression. The 28-day compressive strength of CPB can reach 8 MPa, the residual strength is about 1∼2 MPa, the elastic modulus is about 200∼2000 MPa, and the porosity is about 3∼5%. The CPB with slurry concentration of 74% and 76% and cement-tailings ratio of 1 : 4 and 1 : 6 is more reasonable, and the relevant mechanical parameters are more stable.


2021 ◽  
Vol 4 (2) ◽  
pp. 53
Author(s):  
Yusep Muslih Purwana ◽  
Bambang Setiawan ◽  
Raden Harya Danajaya ◽  
Brilliant Bagaskara

<p>Plasticine is an artificial material made from solids such as gypsum, lime, mixed with petroleum jelly or micro wax and acid fat. The properties of plasticine are likely similar to natural clay and is influenced by oil content. The information about mechanical properties of plasticine is still very rare, and as such the study on it is riquired and must be conducted intensively. The preliminary laboratory study has been conducted to understand the behaviour of plasticines. Microwax and petroleum jelly based plasticines were utilised with the variation of oil content, whereas kaolin clay with the variation of water content is utilised as a reference material. The study is focusing on the stress-strain behaviour for both microwax and petroleum jelly based plasticines compared to the stress-strain behaviour of kaolin clay. This paper reports the result of preliminary investigation regarding the use of plasticine as an alternative artificial material for substitution of clay in soil modeling. Some engineering properties from unconfined compression strength (UCS) test and hand penetrometer are shown. The result indicates that the stress-strain behaviour of plasticine resembles the stress-strain behaviour of kaolin clay. The plasticine is suitable as a substitute cohesive material and it has a potential to be utilised for geotechnical material modelling in the future.</p>


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