Excessively Wet Subgrade Improvement with 100% Industry By-Products for Heavy Traffic Pavement – I. Solidification and Compaction Characteristics of Treated Soil

2010 ◽  
Vol 113-116 ◽  
pp. 1560-1564
Author(s):  
Xi Zhong Yuan ◽  
Fei Liu ◽  
Wei Cui ◽  
Cheng Cheng Liu
Keyword(s):  
Heavy Traffic ◽  
High Volume ◽  
Site Investigation ◽  
Engineering Properties ◽  
Traffic Condition ◽  
Dynamic Cone Penetrometer ◽  
Green Materials ◽  
Free Moisture ◽  
Stabilized Soil ◽  
Solids Content

Deformation of excessively wet subgrade is often problematic during pavements construction as well as under regular vehicular traffic loads. In order to create a sturdy and stable platform for heavy traffic pavement, a “green materials” based entirely on industry byproduct of combination fly ash (FA) with carbide lime (CL) and flue gas desulfurization gypsum (FGDG) was proposed in this study. In order to investigate the effectiveness and improvement of engineering properties, solidification test and compaction test were carried out in laboratory, and Dynamic Cone Penetrometer (DCP) was conducted at the construction site. Investigation results showed significant improvement in drying rate, workability, and mechanical behavior. The addition of FA/CL/FDG stabilizer increases the solids content by “bulking” and reduces the free moisture through hydration reactions. The addition of FA/CL/FGDG leads to an increase of approximately 18% in the maximum allowable moisture content, which would largely facilitate the compaction of the excessively wet soils. Post construction evaluation using DCP indicates the stabilized soil can be utilized under high volume traffic condition.

Engineering properties of lightweight aggregate concrete containing limestone powder and high volume fly ash

2016 ◽  
Vol 135 ◽  
pp. 148-157 ◽  
Author(s):  
Payam Shafigh ◽  
Mohammad A. Nomeli ◽  
U. Johnson Alengaram ◽  
Hilmi Bin Mahmud ◽  
Mohd Zamin Jumaat
Keyword(s):  
Fly Ash ◽  
Lightweight Aggregate ◽  
High Volume ◽  
Limestone Powder ◽  
Engineering Properties ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
High Volume Fly Ash

Effect of Lime on Compaction, Strength and Consolidation Characteristics of Pontian Marine Clay

2015 ◽  
Vol 72 (3) ◽  
Author(s):  
Siaw Yah Chong ◽  
Khairul Anuar Kassim
Keyword(s):  
Construction Material ◽  
Soft Clay ◽  
Engineering Properties ◽  
Dry Density ◽  
Marine Clay ◽  
Maximum Dry Density ◽  
Stabilization Phase ◽  
Compaction Curve ◽  
Stabilized Soil

Marine clay is a problematic construction material, which is often encountered in Malaysian coastal area. Previous researchers showed that lime stabilization effectively enhanced the engineering properties of clay. For soft clay, both strength and consolidation characteristics are equally important to be fully understood for design purpose. This paper presented the effect of lime on compaction, strength and consolidation characteristics of Pontian marine clay. Compaction, unconfined compression, direct shear, Oedometer and falling head permeability tests were conducted on unstabilized and lime stabilized samples at various ages. Specimens were prepared by compaction method based on 95 percent maximum dry density at the wetter side of compaction curve. It was found that lime successfully increased the strength, stiffness and workability of Pontian marine clay; however, the permeability was reduced. Unconfined compressive strength of stabilized soil was increased by 49 percent at age of 56 days whereas compressibility and permeability was reduced by 48 and 67 percent, respectively. From laboratory tests, phenomenon of inconsistency in engineering characteristics was observed for lime stabilized samples below age of 28 days. This strongly proved that lime stabilized soil underwent modification phase before stabilization phase which provided the long term improvement.

scholarly journals CHARACTERIZING A TROPICAL SOIL VIA SEISMIC IN SITU TESTS

2019 ◽  
Vol 37 (3) ◽  
pp. 263
Author(s):  
Breno Padovezi Rocha ◽  
Heraldo Luiz Giacheti
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soil Profile ◽  
Site Investigation ◽  
Tropical Soil ◽  
Engineering Properties ◽  
Foundation Engineering

ABSTRACT. The shear wave velocity (Vs) is an important geotechnical parameter to be used in dynamic problems (e.g. earthquakes and vibration problems) as well as in static deformation analysis such as excavations and foundation engineering design. There are several in situ seismic tests to determine Vs such as the crosshole and the downhole techniques, as well as hybrid tests (e.g. seismic dilatometer – SDMT). This paper presents crosshole, downhole and SDMT tests carried out in a typical tropical soil profile from Brazil. Advantages and limitations regarding the test procedures and interpretation are briefly presented and differences observed among Vs determined by these techniques are discussed. Shear wave velocities (Vs) estimated from the crosshole, downhole and SDMT tests ranging from 194 to 370 m/s. The shear wave velocity suggests that the experimental site could be divided into two strata, which are in agreement with soil profile description. The maximum shear modulus (G0) calculated from the Vs by theory of elasticity can be used to show the investigated tropical soil is a typical unusual geomaterial. This article also emphasizes that the SDMT is a useful test for site investigation since it allows a great means for profiling geostratigraphy and soil engineering properties during routine site investigation as well as for dynamics problems. Keywords: shear wave velocity, maximum shear modulus, crosshole, downhole, SDMT.RESUMO. A velocidade de onda cisalhante (Vs) é um parâmetro geotécnico empregado em análises dinâmicas (terremotos e problemas de vibração), bem como em análises estáticas (escavações e projeto de fundações). Existem vários ensaios sísmicos de campo para a determinação de Vs, entre eles as técnicas crosshole e downhole, e os ensaios híbridos (por exemplo, dilatômetro sísmico – SDMT). Este artigo apresenta os ensaios crosshole, downhole e SDMT realizados em um perfil típico de solo tropical do Brasil, as vantagens e limitações dos procedimentos de ensaio e de interpretação são brevemente apresentadas, e as diferenças observadas entre os valores de Vs determinados pelas diferentes técnicas são discutidas. Os perfis de Vs determinados pelas diferentes técnicas variaram de 194 a 370 m/s. A velocidade da onda cisalhante sugere que o campo experimental investigado pode ser dividido em dois horizontes, os quais estão de acordo com a descrição do perfil do solo estudado. O módulo de cisalhamento máximo (G0), calculado a partir de Vs pela teoria da elasticidade, pode ser utilizado para demonstrar o comportamento não convencional do solo investigado. Este artigo também enfatiza que o SDMT é um ensaio geotécnico útil para a investigação geotécnica do subsolo, uma vez que permite a definição do perfil estratigráfico e a estimativa de parâmetros estáticos e dinâmicos de um projeto.Palavras-chave: velocidade de onda cisalhante, módulo de cisalhamento máximo, crosshole, downhole, SDMT.

Improving engineering properties of mature fine tailings using Tubifex

2020 ◽  
Vol 47 (7) ◽  
pp. 812-821
Author(s):  
Xiaojuan Yang ◽  
Miguel de Lucas Pardo ◽  
Maria Ibanez ◽  
Lijun Deng ◽  
Luca Sittoni ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Engineering Properties ◽  
Test Results ◽  
Sulfate Content ◽  
Mature Fine Tailings ◽  
Fine Tailings ◽  
The Mean ◽  
Solids Content

The present study investigated the effects of Tubifex (Oligochaeta: Tubificidae) treatment on the dewatering process of mature fine tailings (MFT). Experiments testing the survival rate showed that Tubifex can survive at 20 °C and 4 °C. MFT with initial solids content (Sc) of 30% of total mass were treated in 11 settling columns by three Tubifex densities, 1400, 2000 and 4200 individuals·m−2. Test results showed that the mean survival rate at 20 °C and 4 °C on the 28th day stayed around 85%. Tubifex enhanced MFT dewatering by providing compacted tailings with 11.6% and 66.7% higher Sc and undrained shear strength compared with nontreated tailings. Tubifex accelerated pore water pressure dissipation. Tubifex did not affect the chemical composition of tailings except for a decrease in sulfate content. The Sc of tailings treated by Tubifex increased by 67.4% within nine months, which was 129% greater than the Sc increase of the nontreated tailings after 11 months.

Fatigue and Engineering Properties of Chemically Stabilized Soil for Pavements

2012 ◽  
Vol 43 (1) ◽  
pp. 96-104 ◽  
Author(s):  
B. M. Lekha ◽  
A. U. Ravi Shankar ◽  
Goutham Sarang
Keyword(s):  
Engineering Properties ◽  
Stabilized Soil

A limit theorem for priority queues in heavy traffic

1973 ◽  
Vol 10 (04) ◽  
pp. 907-912 ◽  
Author(s):  
J. Michael Harrison
Keyword(s):  
Limit Theorem ◽  
Queueing System ◽  
Heavy Traffic ◽  
Critical Value ◽  
Single Server ◽  
Traffic Condition ◽  
Transient Distribution ◽  
Virtual Waiting Time ◽  
Waiting Time Process ◽  
Priority Queueing

A single server, two priority queueing system is studied under the heavy traffic condition where the system traffic intensity is either at or near its critical value. An approximation is developed for the transient distribution of the low priority customers' virtual waiting time process. This result is stated formally as a limit theorem involving a sequence of systems whose traffic intensities approach the critical value.

Excessively Wet Subgrade Improvement with 100% Industry By-Products for Heavy Traffic Pavement – II. Mechanical Behavior and Durability of Stabilized Soils

2010 ◽  
Vol 113-116 ◽  
pp. 1429-1432
Author(s):  
Xi Zhong Yuan ◽  
Cheng Cheng Liu ◽  
Wei Cui ◽  
Fei Liu
Keyword(s):  
Mechanical Behavior ◽  
Heavy Traffic ◽  
Dry Weight ◽  
Strength Loss ◽  
Systematic Investigation ◽  
Treated Soil ◽  
Freeze Thaw ◽  
Volumetric Expansion ◽  
Green Materials ◽  
Compaction Degree

The workability of excessively wet subgrade can be effectively improved by using a “green materials” based entirely on industry byproduct of combination of fly ash (FA) with carbide lime (CL) and flue gas desulfurization gypsum (FGDG). This paper presents the results of a further systematic investigation on the mechanical behavior and durability of FA/CL/FGDG treated silt from Dezhou in Shandong province. FA, CL and FGDG were added at 3 levels in percentages of 8%-24%, 2%-6% and 1%-3% by dry weight of the soils, respectively. The unconfined compressive strength as well as splitting tensile strength (STS), volumetric expansion (VE), California bearing ratio (CBR), dry-wet cycles test and freeze-thaw cycles test were performed. The best strength of 0.802MPa was achieved for 24%FA/6%CL/1%FGDG treated soil, while the 16%FA/6%CL/1%FGDG treated soil also produce good strengths of 0.742MPa, after 7 days curing. STS keeps increasing with curing period in the first 8 weeks throughout the investigation. According to the VE test, a mellowing period may help prevent swelling from ettringite precipitation by letting these minerals form and hydrate before compaction. The FA/CL/FGDG treated soil has a better durability with strength loss ratio less than 15% after 10 wet-dry cycles, and the maximum weight loss around 25% after 10 freeze–thaw cycles. CBR decreases with decrease of compaction degree, but the values are still around 70 even in a poor compaction degree of 93%, meeting the general requirements of subgrade. So, if the silt subgrade is in excessively wet state and could not be compacted to the required density, the modified subgrade would still serve as a strong platform and could provide necessary support for pavement.

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