scholarly journals Compaction and Collapse Characteristics of Dune Sand Stabilized with Lime-Silica Fume Mix

2016 ◽  
Vol 20 (2) ◽  
pp. 1 ◽  
Author(s):  
Mohammed Y. Fattah ◽  
Hasan H. Joni ◽  
Ahmed S. A. Al-Dulaimy
Keyword(s):  
Silica Fume ◽  
Soil Stabilization ◽  
Ground Improvement ◽  
Construction Materials ◽  
California Bearing Ratio ◽  
Dune Sand ◽  
Dune Sands ◽  
Maximum Percentage ◽  
Collapse Characteristics ◽  
Sand Stabilized

The purpose of this research is to assess the suitability of dune sands as construction materials. Moreover, such a goal is considered beneficial in determining appropriate methods for soil stabilization or ground improvement and to assessing the suitability of dune sands as subgrade layer for carrying roads and rail foundation. Dune sand samples were collected from a region in Baiji area in Salah-Aldeen governorate, North of Iraq. A grey-colored densified silica fume (SF) and lime (L) are used. Three percentages are used for lime (3%, 6%, and 9%), and four rates are used for silica fume (3%, 6%, 9% and 12%) and the maximum percentage of silica fume is mixed with the proportions of lime. Unsoaked California Bearing Ratio (CBR) on compacted dune sands treated dune sands with L-SF by mixing and cured for one day. The increasing in CBR ranged between 443 – 707% at 2.54 mm penetration and 345 – 410% at 5.08 mm penetration.   ResumenEl propósito de esta investigación es evaluar el uso de arena de dunas como materiales de construcción. Además, este objetivo permite determinar los métodos apropiados para la estabilización del suelo, el mejoramiento del terreno y la evaluación de pertinencia de la arena de dunas en capas subbase para carreteras y cimientos férreos. Se recolectaron muestras de arena de dunas en el área de Baiji, del comisionado Salah-Aldeen, al norte de Irak. Se utilizó vapor de óxido de silicio (SF, en inglés), grisáceo y densificado, y óxido de calcio (L). Se utilizaron tres porcentajes para el óxido de calcio (3 %, 6 % y 9 %), y cuatro para el óxido de silicio (3 %, 6 %,  9% y 12%) y el máximo porcentaje del óxido de silicio se mezcló con las proporciones de óxido de calcio. Se realizó en seco el Ensayo de Relación de Soporte de California (del inglés California Bearing Ratio, CBR) en arena de dunas compactada y tratada con la mezcla L-SF curada durante un día. El incremento en el ensayo CBR osciló entre 443-707 % en la penetración de 2.5 mm y 345-410 % en la penetración de 5.08 mm.

Strength characteristics of dune sand stabilized with lime-silica fume mix

2016 ◽  
Vol 19 (10) ◽  
pp. 874-882 ◽  
Author(s):  
Mohammed Y. Fattah ◽  
Hasan H. Joni ◽  
Ahmed S. A. Al-Dulaimy
Keyword(s):  
Silica Fume ◽  
Strength Characteristics ◽  
Dune Sand ◽  
Sand Stabilized

scholarly journals Performance of soft clay stabilized with sand columns treated by silica fume

2018 ◽  
Vol 162 ◽  
pp. 01007
Author(s):  
Zeena Samueel ◽  
Hussein Karim ◽  
Mohammed Mohammed
Keyword(s):  
Silica Fume ◽  
Carrying Capacity ◽  
Construction Projects ◽  
Ground Improvement ◽  
Soft Clay ◽  
Road Construction ◽  
Reduction Ratio ◽  
Area Replacement Ratio ◽  
Second Category ◽  
Improvement Ratio

In many road construction projects, if weak soil exists, then uncontrollable settlement and critical load carrying capacity are major difficult problems to the safety and serviceability of roads in these areas. Thus ground improvement is essential to achieve the required level of performance. The paper presents results of the tests of four categories. First category was performed on saturated soft bed of clay without any treatment, the second category shed light on the improvement achieved in loading carrying capacity and settlement as a result of reinforcing with conventional sand columns at area replacement ratio = 0.196. The third set investigates the bed reinforced by sand columns stabilized with dry silica fume at different percentages (3, 5 and 7%) and the fourth set investigates the behavior of sand columns treated with slurry silica fume at two percentages (10 and 12%). All sand columns models were constructed at (R.D= 60%). Model tests were performed on bed of saturated soil prepared at undrained shear strength between 16-20 kPa for all models. For all cases, the model test was loaded gradually by stress increments up to failure. Stress deformation measurements are recorded and analyzed in terms of bearing improvement ratio and settlement reduction ratio. Optimum results were indicated from soil treated with sand columns stabilized with 7% dry silica fume at medium state reflecting the highest bearing improvement ratio (3.04) and the settlement reduction ratio (0.09) after 7 days curing. While soil treated with sand columns stabilized with 10% slurry silica fume provided higher bearing improvement ratio 3.13 with lower settlement reduction ratio of 0.57 after 7-days curing.

Systematic approach to assessing the applicability of fly-ash-based geopolymer for clay stabilization

2020 ◽  
Vol 57 (9) ◽  
pp. 1356-1368 ◽  
Author(s):  
Hayder H. Abdullah ◽  
Mohamed A. Shahin ◽  
Megan L. Walske ◽  
Ali Karrech
Keyword(s):  
Fly Ash ◽  
Systematic Approach ◽  
Soil Stabilization ◽  
Ground Improvement ◽  
Experimental Program ◽  
Attractive Alternative ◽  
Chemical Additives ◽  
Soil Mineralogy ◽  
Problematic Soils ◽  
Ph Level

Traditional soil stabilization by chemical additives such as cement and lime is a well-established technique for ground improvement of problematic soils. However, with the advantage of lower carbon emission and energy consumption, fly-ash-based geopolymer has recently become an attractive alternative to traditional stabilizers. Nevertheless, the literature lacks systemic approaches that assist engineers to apply this promising binder for soil stabilization, including the proper dosages required for an effective treatment. This paper introduces a systematic approach to assess the applicability of fly-ash-based geopolymer for stabilization of clay soils, through a comprehensive experimental program where engineered and natural clays were examined and evaluated, including soil compaction, plasticity, compressive strength, durability, pH level, and impact of pulverization. The results revealed several factors that influence the level of enhancement of geopolymer-treated clays, including the soil mineralogy, plasticity–activity properties, geopolymer concentration, curing time, and pulverization.

scholarly journals Geotechnical properties of reinforced clayey soil using nylons carry’s bags by products

2018 ◽  
Vol 162 ◽  
pp. 01020 ◽  
Author(s):  
Nahla Salim ◽  
Kawther Al-Soudany ◽  
Nora Jajjawi
Keyword(s):  
Soil Stabilization ◽  
Clayey Soil ◽  
Ground Improvement ◽  
Soft Soil ◽  
Liquid Limit ◽  
Waste Material ◽  
Industrial Wastes ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Replacement Technique

All structures built on soft soil may experience uncontrollable settlement and critical bearing capacity. This may not meet the design requirements for the geotechnical engineer. Soil stabilization is the change of these undesirable properties in order to meet the requirements. Traditional methods of stabilizing or through in-situ ground improvement such as compaction or replacement technique is usually costly. Now a safe and economic disposal of industrial wastes and development of economically feasible ground improvement techniques are the important challenges being faced by the engineering community. This work focuses on improving the soft soil brought from Baghdad by utilizing the local waste material for stabilization of soil, such as by using “Nylon carry bag’s by product” with the different percentage and corresponding to 1 %, 3% and 5% (the portion of stabilizer matters to soil net weight) of dried soil. The results indicated that as Nylon’s fiber content increases, the liquid limit decreases while the plastic limit increases, so the plasticity index decreases. Furthermore, the maximum dry density decreases while, the optimum moisture content increases as the Nylon’s fiber percentage increases. The compression index (decreases as the Nylon’s fiber increases and provides a maximum of 43% reduction by adding 5% nylon waste material. In addition, the results indicated that, the undrained shear strength increases as the nylon fiber increases.

scholarly journals Artificial biocrust establishment on materials of potash tailings piles along a salinity gradient

2021 ◽  
Author(s):  
V. Sommer ◽  
A. Palm ◽  
A. Schink ◽  
P. Leinweber ◽  
N. Gose ◽  
...  
Keyword(s):  
Sodium Alginate ◽  
Soil Stabilization ◽  
Salinity Gradient ◽  
Bare Soil ◽  
Photosynthetic Performance ◽  
Dune Sand ◽  
Future Studies ◽  
Sand Surface ◽  
Salt Gradient ◽  
Hydrological Cycles

Abstract Biocrust communities provide a pallet of ecosystem services, such as soil stabilization, altering of hydrological cycles and primary production, and often are the first colonizers of unvegetated surfaces during succession. Therefore, artificially establishing biocrusts can improve soil properties, for example, by stabilizing bare soil surfaces against erosion or by accumulating nutrients. In this study, the establishment of artificial biocrusts was tested for the restoration of potash tailings piles that result from potash fertilizer production and mostly consist of NaCl. A biocrust cover as primary vegetation could decrease the saline seepage waters by trapping rainwaters, thereby reducing the environmental pollution. In a laboratory experiment, we created a salt gradient by mixing the tailings materials with non-saline dune sand. Surface material of the abandoned potash tailings pile Neuhof-Ellers (NE) and material of the Infiltration Hampering Stratum (IHS) were tested, along with a treatment with bone charplus (BCplus) and sodium alginate. A mixture of 50% (w/w) IHS and dune sand was most successful for the establishment of green biocrust microalgae, based on increased biomass and photosynthetic performance. The chlorophyll a content was negatively correlated with the electrical conductivity (EC), and was significantly increased in the BCplus and sodium alginate treatment, while biocrusts failed to establish on pure tailings piles substrates. The limit of the substrates EC for biocrust establishment was 35 mS cm−1. This limit provides a baseline for future studies that should use BCplus and sodium alginate to increase the success of biocrust establishment on potash tailings piles.

scholarly journals Reuse of Urban Soils as Earthworks Material: Geotechnical and Environmental Specifications

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 3
Author(s):  
Lenoir
Keyword(s):  
Urban Soils ◽  
Soil Stabilization ◽  
Construction Materials ◽  
Point Of View ◽  
Crucial Issue ◽  
Common Features ◽  
Crucial Problem ◽  
Promising Solution ◽  
Mechanical Performances ◽  
Resource Shortage

In the context of urban extension, the depletion of natural resources for construction constitutes a crucial issue. Specifically, in the field of earthworks, the amounts of materials can be massive and pose the crucial problem of resource shortage. Therefore, the reuse of excavated urban soils from foundation layers as new earthwork construction materials appears to be a sustainable and promising solution. Two questions are thus asked: (1) Are urban soils relevant from a geotechnical point of view? (2) Are they relevant from an environmental point of view? To answer those issues, two urban soils from the suburb of Paris (France) have been studied. Geotechnical approach and environmental approach exhibit that both soils have common features. Specifically, they are bearer of several pollutant phases like metals, organic carbon and sulphates. Interestingly, those materials, when treated with few percent of hydraulic binders reach required mechanical performances for a use in road structure despite the occurrence of pollutants that are known to have deleterious effects on soil stabilization with lime and cements. However, even if permeability of materials is reduced when they are treated with cement, leaching tests under neutral pH (7) and alkaline pH (12) show, that treatment could have inhibitor effects or activating effects on pollutants release.

Late Pleistocene Eolian Sediments Related to Pyroclastic Eruptions of Mauna Kea Volcano, Hawaii

1997 ◽  
Vol 47 (3) ◽  
pp. 261-276 ◽  
Author(s):  
Stephen C. Porter
Keyword(s):  
Late Pleistocene ◽  
Sand Dunes ◽  
Primary Source ◽  
Cinder Cone ◽  
Lava Flows ◽  
Trade Wind ◽  
Stratigraphic Correlation ◽  
Dune Sand ◽  
Dune Sands ◽  
Eolian Sediments

Loess and dune sands that mantle volcanic rocks on the northwest flank of Mauna Kea volcano consist predominantly of fine-grained pyroclasts of the alkalic Laupahoehoe Volcanics produced by explosive eruptions. The loess is divided into lower and upper units, separated by a well-developed paleosol, while older and younger dune sands are separated by loess. Four interstratified tephra marker horizons aid in regional stratigraphic correlation. Radiocarbon ages of charcoal fragments within the loess, U-series ages of rhizoliths in the dune sand, and K/Ar ages and relative stratigraphic positions of lava flows provide a stratigraphic and temporal framework. The lower loess overlies lava flows less than 103,000 ± 10,000 K/Ar yr old, and14C dates from the paleosol developed at its top average ca. 48,000 yr. Loess separating the dune sand units ranges from ca. 38,000 to 25,00014C yr old; the youngest ages from the upper loess are 17,000–18,00014C yr B.P. Dips of sand-dune foreset strata, isopachs on the upper loess, and reconstructed isopachs representing cumulative thickness of tephra associated with late-Pleistocene pyroclastic eruptions suggest that vents upslope (upwind) from the sand dunes were the primary source of the eolian sediments. Average paleowind directions during the eruptive interval (ca. 50,000–15,000 yr B.P.), inferred from cinder-cone asymmetry, distribution of tephra units, orientation of dune foreset strata, and the regional pattern of loess isopachs, suggest that Mauna Kea has remained within the trade-wind belt since before the last glaciation.

Shear Strength of BC-Soil Admixed with Lime and Bio-Enzyme

2019 ◽  
Vol 969 ◽  
pp. 327-334
Author(s):  
C. Jairaj ◽  
M.T. Prathap Kumar ◽  
H. Muralidhara
Keyword(s):  
Shear Strength ◽  
Soil Stabilization ◽  
Morphological Changes ◽  
Ground Improvement ◽  
High Strength ◽  
Sem Analysis ◽  
Dry Density ◽  
Test Results ◽  
Maximum Dry Density ◽  
Lime Content

This BC Soil are expansive in nature and are problematic because of low shear strength and high compressibility. Review of literatures have proven that addition of lime imparts high strength with a corresponding reduction in swell of BC soils. In addition, Bio-enzymes have also been found to play a key role as activators in improving the characteristics of clayey soils such as BC soil. Development and use of non-traditional ground improvement techniques such as bio-enzymes in combination with lime for soil stabilization helps to reduce the cost and the detrimental effects on the soil environment. In the present study lime and bio-enzymes were used as soil stabilizing agents. Compaction test results on BC soil admixed with different percent of lime indicated that 3% addition lime gives higher maximum dry density of 17kN/m3 with OMC of 21% compare to other addition of lime percentages. Keeping 3% of lime as optimum lime content(OLC), BC Soil was admixed with different dosages of Bio-enzymes 25ml/m3, 50ml/m3, 100 ml/m3,150ml/m3, and 200ml/m3 along with OLC was tested for compaction and unconfined compressive strength(UCC). Further UCC test was carried out for different curing period of 0, 7, 15, 30, and 60 Days to analyse the long term effect of BC soil admixed with bio-enzymes with and without lime content. Morphological and chemical analysis was done by using XRD and SEM analysis, from all the test results it was found that 3%OLC + 75ml/m3 of bio-enzymes for 7 day of curing gives higher UCC of 450 kPa. From the SEM it was found that better bond between particles found to develop in bio-enzyme+ lime admixed BC soil in comparison with lime alone admixed BC soil. XRD studies indicated morphological changes in crystallinity and structure of stabilized BC soil in comparison to BC soil alone.

Shrinkage of Blended Cement Pastes with Mineral Additions

2013 ◽  
Vol 539 ◽  
pp. 55-59
Author(s):  
Yi Chen ◽  
Wu Yao ◽  
Dan Jin
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Construction Materials ◽  
Blended Cement ◽  
Cement Pastes ◽  
Mercury Intrusion ◽  
Mineral Additions ◽  
By Products

Mineral additions such as fly ash and silica fume are industrial by products, and play an important role in properties improvement for construction materials. In this work, the shrinkage of cement paste blended with fly ash and silica fume by different substitute ratio was studied. Pore structures of specimens at different ages were determined by mercury intrusion porosimetry (MIP) and shrinkage deformation was measured by standard shrinkage tests. The effects of mineral addtions on shrinkage were discussed. The results show that the fly ash was significantly effective on shrinkage at early ages. Based on the research, several suitable advices were offered to optimize the performances of materials and reduce the shrinkage.

Hydration Process of Portland Cement Blended with Silica Fume

2013 ◽  
Vol 699 ◽  
pp. 578-583 ◽  
Author(s):  
Neven Ukrainczyk ◽  
Jure Zlopasa ◽  
Eduard Koenders
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Isothermal Calorimetry ◽  
Construction Materials ◽  
Radical Change ◽  
Sustainable Construction ◽  
Hydration Kinetics ◽  
Replacement Ratio ◽  
Cement Production ◽  
Ultrasound Bath

The enormous carbon footprint associated with the global cement production (5-7%) asks for a radical change in the use of sustainable replacement materials in concrete. Replacement of cement by pozzolanic waste materials, being a by-product from industrial processes, has been widely recognized as the most promising route towards sustainable construction materials. This paper presents experimental study on hydration of commercial Portland cement blended with silica fume in replacement ratio of 15 mass %. Isothermal calorimetry was employed to monitor the hydration kinetics. Thermogravimetric analysis coupled by differential scanning calorimeter (TG/DSC) was used to investigate the formed hydration products at 1, 3, 7, and 28 days of hydration. Two different approaches for a dispersion of silica fume in cement paste were compared: ultrasound bath and addition of superplasticizer (polycarboxylic ether based).

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