Permeability of Expansive Soils Modified/Stabilized with lime (Review Paper)

2021 ◽  
Vol 14 (2) ◽  
pp. 129-140
Author(s):  
Muwafaq Awad ◽  
Ibrahim Al-Kiki ◽  
Amina Khalil
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Pozzolanic Reaction ◽  
Curing Temperature ◽  
Curing Time ◽  
Short Term ◽  
Coefficient Of Permeability ◽  
Review Study ◽  
Time Periods

The aim of this paper was to review the mechanism of the expansive soil-lime reactions: short term and long-term reactions in both lime modification and lime stabilization. The focus of the study was the effect of curing time for a certain centigrade 25C curing temperature in both lime modification / stabilization-expansive soils on the coefficient of permeability. Peer reviewed articles published between 2000- and 2019 were collected and relevant data were extracted. Results of this review study showed that the coefficient of permeability of expansive soils modified with lime increased during the first 7 days of curing time at curing temperature 25C and it remains constant or slightly decreased for longer curing time periods. However, for expansive soils stabilized with lime, it was found that the coefficient of permeability increased during the first 7-day curing time at curing temperature 25C, then decreased during the longer curing time periods (pozzolanic reaction). It is also noted that even though the coefficient of permeability decreased during pozzolanic reaction, it remains higher than that of the untreated soils

scholarly journals Experimental Study on Dynamic Resilient Modulus of Lime-Treated Expansive Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Zheng Lu ◽  
Yang Zhao ◽  
Shaohua Xian ◽  
Hailin Yao
Keyword(s):  
Moisture Content ◽  
Environmental Changes ◽  
Resilient Modulus ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
The Stability ◽  
Compaction Degree

Dynamic resilient modulus is the design index of highway subgrade design code in China, which is significantly affected by the traffic loads and environmental changes. In this study, dynamic triaxial tests were conducted to investigate the influence of moisture content, compaction degree, cyclic deviator stress, and confining pressure on lime-treated expansive soil. The suitability of UT-Austin model to lime-treated expansive soils was verified. The results indicate that the dynamic resilient modulus of lime-treated expansive soils increases nonlinearly with the increase of compaction degree, while decreases nonlinearly with the increase of dynamic stress level. The dynamic resilient modulus decreases linearly with the increase of moisture content and increases linearly with the increase of confining pressure. Moreover, the moisture content has a more significant effect on the dynamic resilient modulus of lime-treated expansive soil. Therefore, it is necessary to ensure the stability of soil humidity state and its excellent mechanical properties under long-term cyclic loading for the course of subgrade filling and service. Finally, the calculated results of the UT-Austin model for dynamic resilient modulus show a good agreement with the test results.

Long-Term Interaction

2011 ◽  
pp. 169-183
Author(s):  
Christoph Haffner ◽  
Thorsten Völkel
Keyword(s):  
Working Memory ◽  
Interactive Television ◽  
Theoretical Models ◽  
Short Term ◽  
Time Periods ◽  
Potential Impact

This chapter introduces the application of concepts for long-term interaction to support long-term relationship in the interactive television (iTV) domain. While classical interaction concepts cover short-term interaction cycles only, theoretical models for long-term interaction and relationships deal with time periods exceeding the human short-term working memory. The user must be supported by memory cues to resume interrupted long-term interactions immediately. The iTV domain offers many long-term interaction scenarios in the context of establishing long-term relationships of recipients and broadcasters. The authors adopt concepts for long-term interaction towards iTV and develop a basic classification of long-term interaction. Three scenarios within the iTV domain illustrate the potential impact for the design of iTV applications.

scholarly journals Experimental investigation of soil blended with lime and lignosulphonate

2018 ◽  
Vol 7 (2.25) ◽  
pp. 74
Author(s):  
Soundarya M.K ◽  
Bhuvaneshwari S ◽  
Prasanna Kumar.S
Keyword(s):  
Expansive Soils ◽  
Research Work ◽  
Expansive Soil ◽  
Pozzolanic Reaction ◽  
Clay Particles ◽  
Bearing Strength ◽  
Pulp Industry ◽  
Saw Dust ◽  
Change Behavior ◽  
Volume Change Behavior

The deterioration of the structures which are built on the expansive soils is due to its volume change behavior, due to the presence of Mont-morillonite minerals in soil. Hence this soil requires adequate stabilization before commencement of any construction activities. The stabili-zation phenomenon in which addition suitable additives completely alters the behavior of the soil by changing the basic properties and there-by increasing the bearing strength of soil. The choice of the additives depends on the ease and permanence of the stabilizing characteristics achieved for the expansive soil. In this paper, an attempt is done to evaluate the behavior of soil when blended with additives like saw dust ash, lime and lignosulphonate at varying blending ratio. The objective of the research work is to focus on the change in the plasticity charac-teristics by utilizing the industrial waste as additive due to its cementitious value, making it eco-friendly and reduction in cost. Lignosulpho-nate is a by-product of paper pulp industry, generated during the sulphite process. From the literature, the optimum percentage for stabilizing works for lime and lignosulphonate was found to be two to eight percent and one to three percent respectively. Basic Index properties and compaction characteristics test were determined for both virgin and treated soil. The additives decreased the plasticity index, causing ag-glomeration of clay particles involving pozzolanic reaction. 

Mechanical Strength of Lime-Rice Husk Ash Mortars: A Preliminary Study

2012 ◽  
Vol 517 ◽  
pp. 495-499 ◽  
Author(s):  
R. Méndez ◽  
M.V. Borrachero ◽  
J. Payá ◽  
J.M. Monzó
Keyword(s):  
Portland Cement ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Curing Temperature ◽  
Curing Time ◽  
Short Term ◽  
Similar Tendency ◽  
Pozzolanic Material ◽  
Binder Composition ◽  
Preliminary Study

Rice is produced in many countries in the world, and this product permits to feed a lot of people, most of them in developing countries. Approximately one tone of rice produces 200 Kg of rice husk, and when this rice husk is burnt 20% of rice husk ash (RHA) is obtained. A very important part of rice husk is abandoned in the field producing environmental problems. RHA can be obtained by controlled combustion, when this fact occurs, a good quality RHA is produced. This RHA can be used as a pozzolanic material in mixtures with lime or Portland cement, producing good mechanical properties and durability. In this work a preliminary results about the influence of RHA/lime ratio on workability and mortars strength was studied. The results showed that mortars workability improves when RHA/lime ratio do. Compressive strength (Cs) of mortars with different RHA/lime ratios was studied, in this sense, for 28 days curing time at 20°C an increase of Cs when RHA/lime ratio do is observed. However for 90 and 180 days curing time a maximum or Cs for RHA/lime equal to 2 is obtained. The lowest and highest Cs values obtained were 6 and 18 MPa respectively, when 20°C curing temperature was used. When curing temperature increases until 65°C similar tendency of Cs respecting RHA/lime ratio was observed. A preliminary study of binders for using in mortars tiles reveals that at least low quantities of Portland cement must be included in binder composition in order to obtain short term strengths that make easy tile demoulding process.

scholarly journals The mechanical behavior of an expansive soil due to long-term seasonal rainfalls

2020 ◽  
Vol 195 ◽  
pp. 02019
Author(s):  
Kai LI ◽  
Liang Kong ◽  
Hossein Nowamooz ◽  
Cyrille Chazallon
Keyword(s):  
Mechanical Behavior ◽  
Expansive Soils ◽  
Expansive Soil ◽  
Direct Determination ◽  
Model Parameters ◽  
Continuous Change ◽  
Step Method ◽  
Steady Solutions ◽  
Unsaturated Expansive Soils

Expansive soils, susceptible to be affected by the environmental conditions, expand when water is added and shrink when they dry out. This continuous change in soil volume is able to cause structures built on them to move unevenly and crack. To investigate the hydro-mechanical behavior of unsaturated expansive soils, many laboratory tests on these materials have been carried on and numerous models have also been proposed with a relatively large number of parameters. In this study, a simplified model based on Zarka method has been developed for unsaturated expansive soils. The direct determination of the steady solutions in Zarka analysis is able to replace classic step-by-step method and needs less model parameters. In this context, this paper presents a Zarka-based model to predict the volume change in unsaturated expansive soils under seasonal drought and rainfall cycles and the proposed model is implemented in the finite element code to simulate long-term behavior of a 2D structure consisting of expansive soils and subjected to successive drought and rainfall cycles. Finally, the numerical calculation defines the plastic strain field and the inelastic displacement field of the studied structure.

scholarly journals Using Fine Silica Sand and Granite Powder Waste to Control Free Swelling Behavior of High Expansive Soil

2020 ◽  
Vol 15 (1) ◽  
pp. 53
Author(s):  
Manal O. Suliman ◽  
Abdulrazzaq Jawish Alkherret
Keyword(s):  
Expansive Soils ◽  
Expansive Soil ◽  
Critical Issue ◽  
Soil Samples ◽  
Silica Sand ◽  
Swell Index ◽  
Subgrade Soil ◽  
Free Swell ◽  
Granite Powder

Many researchers have been interested in studying the effect of adding local natural materials or construction waste on the properties of poor subgrade soil. However, changes in size and strength of expansive soils can cause extensive damage to the geotechnical infrastructure. This damage is often repeatable and latent in the long term, and is a critical issue in highway subgrade engineering. This paper examines the effect of adding both Fine Silica Sand (FSS) and Granite Cutting Powder Waste (GPW) materials on the welling characteristics of expansive soils. Atterberg limits, free swell index, and rate of swell of the mixtures were used as a key to assess properties of a group of expansive soil samples after adding different percentages of the mentioned materials. The rates of additions were 10%, 20%, 30%, 40%, 50%, 60 and 70% of the weight of the soil samples. The test results showed that FSS and GPW significantly affect the expansive soil properties. However, adding 70% of both FSS and GPW reduced the swelling index from 58.3% to 6.6% and from 58.3% to 11% after 7 days of curing, respectively. This study suggests that the Fine Silica Sand and Granite Powder Waste can be used as stabilizers for expansive highly plastic soils.

A Review on the Effect of Fly Ash, RHA and Slag on the Synthesizing of Coal Bottom Ash (CBA) Based Geopolymer

2021 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Nor Farhana Binti Ab Gulam ◽  
A. B. M. Amrul Kaish ◽  
Abir Mahmood ◽  
Sudharshan N. Raman ◽  
Maslina Jamil ◽  
...  
Keyword(s):  
Fly Ash ◽  
Erosion Resistance ◽  
Rice Husk Ash ◽  
Lightweight Concrete ◽  
Bottom Ash ◽  
Curing Temperature ◽  
Curing Time ◽  
Construction Sector ◽  
Coal Bottom Ash

Geopolymerization is widely used in the construction sector for its characteristics of strong compressive strengths, quick hardening, long-term durability, fire resistance, and erosion resistance. This paper has gone through the geopolymer performances utilizing coal bottom ash (CBA), CBA blended with fly ash (FA), CBA mixed together with slag, and CBA with rice husk ash (RHA). CBA shows a better performance than FA in the compressive strength. This paper has discovered several elements that influence geopolymerization, the curing time, the curing temperature, the silicate and hydroxide ratio, and grinding CBA surfaces. The combination of CBA and RHA is suitable for lightweight concrete, as the range of the volumetric weight is within 1192 kg/m3 to 1655 kg/m3. The slump result decreases, as the ratio of CBA and slag increases. Slag particles are uneven in shape, which increases water consumption and leads to a honeycombed structure, whereas CBA particles are spherical in shape, which enhances workability.

Short- and Long-Term Effects of Auxiliary Labels on Patient Knowledge of Precautionary Drug Information

1988 ◽  
Vol 22 (6) ◽  
pp. 470-474 ◽  
Author(s):  
Candace S. Brown ◽  
Brenda L. Solovitz ◽  
Stephen G. Bryant ◽  
Brock G. Guernsey ◽  
Seymour Fisher
Keyword(s):  
Drug Information ◽  
Controlled Study ◽  
Control Group ◽  
Long Term Effects ◽  
Short Term ◽  
Short And Long Term ◽  
Time Periods ◽  
Experimental Group ◽  
Over Time

The purpose of this study was to determine the efficacy of auxiliary prescription labels in educating outpatients about medicines at two different time periods. Five hundred fifty-nine patients were randomly assigned either to an experimental group or a control group; each person in the experimental group received a prescription bottle to which one study auxiliary label (“sticker”) had been affixed, and those in the control group received bottles with no study sticker attached. Patients were interviewed by telephone approximately one week or two months after prescription pick up. Patients who had the study sticker affixed to their prescription bottle were significantly more knowledgeable after one week about precautionary information than those patients who did not receive stickers; however, sticker-group patients receiving the delayed interview incorrectly attributed many precautions to their medication. This is the first controlled study to document that auxiliary labels increase short-term knowledge about medications, and to suggest that the same labels may result in an inappropriate generalization over time.

The effects of forskolin and LH on cAMP changes and maturation in the follicle-enclosed oocytes of hamsters

1985 ◽  
Vol 110 (3) ◽  
pp. 413-420 ◽  
Author(s):  
C.J. Hubbard
Keyword(s):  
Oocyte Maturation ◽  
Transient Increase ◽  
Short Term ◽  
Significant Percentage ◽  
Transient Rise ◽  
Dramatic Rise ◽  
Time Periods ◽  
Camp Levels

Abstract. Graafian follicles from mature pro-oestrous hamsters were incubated with LH, various concentrations of forskolin, or forskolin plus LH. The incubations were either terminated at different time periods for analysis of follicular or oocyte cAMP levels or incubated for the entire 6 h and the oocytes examined to determine maturational status. Incubations with LH (1 μg/ml) produced a short transient rise in follicular and oocyte cAMP concentrations, while forskolin (60 μm, 20 μm and 10 μm) produced cAMP values which remained elevated for longer periods of time. The 1 μm concentration of forskolin initiated oocyte maturation (28%) but at a level which was significantly below that stimulated by LH (74%). When LH was included with forskolin, a dramatic rise in follicular cAMP occurred which was approximately 2 times greater than levels seen with LH alone. A significant percentage of oocytes matured when 100 nm forskolin (45%) was included with LH (I μg/ml) but not with any other concentration of forskolin tested. Maturation percentages for follicle-enclosed oocytes exposed to 1 μm forskolin plus 1 μ/ml of LH (3.8%) were not different from the controls (7%). However, when 1 μm forskolin was combined with 100 ng/ml of LH a significant percentage of oocytes matured (47%). While continuous incubations with forskolin did not stimulate a high percentage of oocytes to mature, oocytes from follicles exposed to forskolin (60 μm and 20 μm) for short periods (5 min–30 min) with a change to plain medium did mature. The results of these studies indicate that, in the hamster, long term exposure to forskolin inhibits maturation in follicle-enclosed oocytes. This appears to be the result of persistently elevated cAMP levels in both the follicle and the oocyte. By contrast, short-term incubations initiate maturation. In these groups, cAMP presumably undergoes a transient increase similar to that which is initiated by LH. Maturation in the follicle-enclosed oocytes of hamsters appears to require both a rise and decline in cAMP.

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