scholarly journals An Eco-Sustainable Stabilization of Clayey Road Subgrades by Lignin Treatment: An Overview and a Comparative Experimental Investigation

2021 ◽  
Vol 11 (24) ◽  
pp. 11720
Author(s):  
Rosolino Vaiana ◽  
Cesare Oliviero Rossi ◽  
Giusi Perri
Keyword(s):  
Clayey Soil ◽  
Experimental Tests ◽  
Test Results ◽  
Bibliographic Analysis ◽  
The Road ◽  
Subgrade Soils ◽  
Road Pavement ◽  
Comparative Experimental Investigation ◽  
And Performance

Subgrade conditions significantly affect functionality of the road pavement during its service life. Among the different stabilization techniques for upgrading poorly performing in-situ soil subgrades, an economically attractive example involves the use of waste materials, such as lignin. A deep bibliographic analysis of previous studies is carried out in the first section of this paper. The literature review suggests that use of lignin as a stabilizing agent of road subgrade soils is not completely consolidated. In addition, this study reports an investigation on the strength and performance characteristics of a lignin-treated clayey soil. Several experimental tests were carried out on both the untreated and lignin-treated soils in order to shed some light on different aspects with limited knowledge available, such as the behaviour of the stabilised soil in specific conditions (e.g., the presence of water). Finally, the test results are discussed and compared with those obtained when the same soil is treated with lime, which is more widely used. The most relevant finding is the poor ability of lignin to upgrade the bearing capacity of the soil in wet conditions compared to lime; on the contrary, the presence of lignin helped in controlling the swelling potential of this type of soil.

Bond of Steel Bars to Masonry Mortar Joints: Test Results and Analytical Modelling

2017 ◽  
Vol 747 ◽  
pp. 319-325 ◽  
Author(s):  
Matteo Maragna ◽  
Cristina Gentilini ◽  
Giovanni Castellazzi ◽  
Christian Carloni
Keyword(s):  
High Strength ◽  
Experimental Tests ◽  
Analytical Investigation ◽  
Masonry Walls ◽  
Test Results ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bars ◽  
Masonry Mortar

In this paper, the preliminary results of a series of pull-out tests conducted on mortar cylinders with embedded bars are presented. The bars are made of high strength stainless steel and are of helical shape to increase mechanical interlocking with the surrounding mortar. Usually, such bars are employed in situ to realize structural repointing in the case of fair-faced masonry walls. To this aim, they are inserted in the mortar bed joints of masonry for providing tensile strength to the walls and with the function of crack stitching. The aim of the present experimental tests is to determine the bond-slip relationship for bars embedded in masonry. Firstly, pull-out tests are conducted on mortar cylinders considering different embedded lengths of the bars. Further tests are on-going on masonry specimens with bars embedded in the mortar joints. An analytical investigation is also carried out for the interpretation of the pull-out test results.

scholarly journals In Situ Measurement of Discomfort Curves for Seated Subjects in a Car on the Four-Post Rig

2014 ◽  
Vol 2014 ◽  
pp. 1-14
Author(s):  
T. Ibicek ◽  
A. N. Thite
Keyword(s):  
Predictive Models ◽  
Dynamic Behaviour ◽  
Rate Of Change ◽  
Test Results ◽  
Vehicle Dynamic ◽  
The Road ◽  
Perceived Intensity ◽  
The Difference ◽  
On The Road

The aim of this study is to measure and quantify perceived intensity of discomfort due to vibration in a vehicle in situ considering complete vehicle dynamic behaviour. The shaker table based discomfort curves or the road test results may not accurately and universally indicate the true level of human discomfort in a vehicle. A new experimental method, using a seated human in a car on the four-post rig simulator, is proposed to quantify discomfort. The intensity of perception to vibration decreased with decreasing input and increasing frequency; the rate of change is different from the published literature; the difference is large for angular modes of inputs. Vehicle dynamic response is used to inform and analyse the results. The repeatability of the method and the fact that they are in situ measurements may eventually help reduce reliance on the road tests. Furthermore, discomfort curves obtained, subsequently, can be used in predictive models.

Root reinforcement of soil: review of analytical models, test results, and applications to design

2013 ◽  
Vol 50 (3) ◽  
pp. 259-274 ◽  
Author(s):  
Tien H. Wu
Keyword(s):  
Analytical Models ◽  
Test Results ◽  
In Situ Tests ◽  
Design Problems ◽  
Root Reinforcement ◽  
And Performance

This paper reviews analytical models that are used to evaluate results of laboratory and in situ tests on soil reinforced by vegetation roots and performance of slopes with vegetation. Predicted and observed performances are compared to illustrate the accuracy and refinement of the models and their relationships to the quality of the available data. General guidelines for application to design problems are provided.

A NEW APPROACH TO REPAIR OF NON-RIGID ROAD PAVEMENT TRANSITIONAL TYPE

2020 ◽  
Vol 264 (4) ◽  
pp. 47-51
Author(s):  
Serhii Holovko ◽  
Keyword(s):  
Crushed Stone ◽  
Significant Heterogeneity ◽  
Fine Aggregate ◽  
The Road ◽  
Subgrade Soils ◽  
Soil Mixing ◽  
Road Pavement ◽  
Local Roads ◽  
On The Road ◽  
Over Time

Earlier, due to insufficient financing of the road industry, funds were allocated on a leftover basis for the repair of local roads, over time the condition of these roads has deteriorated significantly. So, given the ramified network of local roads, the issue of restoring the condition of local roads is a very urgent problem. Conducted exploratory studies of the application of stabilization technology to restore the condition of local roads show that this technology is progressive, since it allows reusing existing materials while ensuring the required strength of the pavement. However, design engineers rarely use this technology, probably due to insufficient research on this approach. The task is to investigate the possibility of using stabilization technology with the use of crushed stone layers of different composition and their maximum reuse, when repairing transitional pavements. Analysis shows that there are many cases where transitional structures have significant heterogeneity and low strength. This is formed due to a weak crushed stone base and waterlogging of the subgrade soils. Over time, soil particles penetrate into the crushed stone layer and weaken the contacts between the crushed stones, as a result of which rut, pits and subsidence form on the road, which significantly complicates the movement of vehicles. Studies of the composition of existing bases show that if in a dispersed system the amount of crushed stone grains is more than 50% by volume, then a contact frame is formed in the material. Intergranular voids are filled with soil or fine aggregate, processing with such a small amount of a mineral binder (cement or lime) allows it to be significantly strengthened, as well as to create bonds between the soil and crushed stone. Modern self-propelled soil mixing machines (recycler-stabilizer) allow in one pass to perform milling (loosening) and mixing of materials of existing transitional pavement to a depth of 40 cm. Taking into account the dependence of the distribution of normal stress in a two-layer half-space, it can be seen that stabilization of the foundation to a depth of 40 cm will allow the subgrade soil to work without exceeding the permissible shear deformations. The construction of the experimental site in Berezivka, Odessa region, confirmed the assumptions about the effectiveness of the proposed solution to restore the strength of transitional pavement. Keywords: non-rigid pavement of transition type, modulus of elasticity, stabilization, rubble, soil, cold recycling.

scholarly journals Evaluation of sample quality from different sampling methods in Finnish soft sensitive clays

2019 ◽  
Vol 56 (8) ◽  
pp. 1154-1168 ◽  
Author(s):  
Bruno Di Buò ◽  
Juha Selänpää ◽  
Tim Tapani Länsivaara ◽  
Marco D’Ignazio
Keyword(s):  
Storage Time ◽  
Soft Clay ◽  
Test Results ◽  
Geotechnical Parameters ◽  
Sample Quality ◽  
Constant Rate ◽  
And Performance

The determination of reliable geotechnical parameters from laboratory testing is highly dependent on sample quality. Over the past decades, undisturbed sampling of soft sensitive clays has been performed using various apparatuses and procedures. This paper outlines details of the design and performance of a new Laval-type tube sampler employed for the investigation of five soft clay sites located in Finland. The investigation was conducted using the new tube sampler and two different piston samplers. The sample quality was evaluated based on the recompression volume during reconsolidation to the in situ effective stress in constant-rate-of-strain oedometer tests. Test results show that tube samples are generally characterized by higher quality, especially in low-plasticity clays. In particular, the quality of piston samples is highly affected by the apparatus condition and sampling operations. Furthermore, the influence of storage time on tube samples was investigated. To guarantee a proper confinement, and thus reduce swelling, a pressurized system was applied to the tube samples obtained in two soft clay sites. Results demonstrate that the sample quality is not significantly affected by storage time as long as the soil is properly stored in the tube.

scholarly journals Micro-mechanical performance evaluation of expansive soil biotreated with indigenous bacteria using MICP method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nitin Tiwari ◽  
Neelima Satyam ◽  
Meghna Sharma
Keyword(s):  
Mechanical Performance ◽  
Clayey Soil ◽  
Treatment Protocol ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Natural Soil ◽  
Split Tensile Strength ◽  
Indigenous Bacteria ◽  
The Road ◽  
Road Pavement

AbstractThis study explored the effect of indigenous bacteria present in the soil to stabilized swelling behavior and improving the mechanical property of expansive soil. The objective of the research is to investigate the effectiveness of the biostimulation microbial induced calcite precipitation (MICP) for controlling the swelling-shrinkage behavior and improving shear strength of expansive soil. An attempt was made to develop an effective procedure to culture the indigenous bacteria for treating clays with varying plasticity and improve their engineering behavior. The detailed procedure has been investigated to effectively apply the MICP technique in clay soil, considering its low permeable nature. The applicability of biostimulation to clayey soils in minimizing their swelling potential and improving the strength is assessed. Both macroscale and microscale studies were conducted on untreated and biostimulated soils to observe changes in plasticity, strength, swelling, mineralogical, chemical characteristics. The present method has shown an effective alternative to improve the road pavement subgrade without affecting the eco-system of natural soil. The method investigated the effective way of providing the enrichment and cementation solution in clayey soil, which is the major concern in current literature. The study confirms that the calcite content has been increased with biostimulated MICP treatment up to 205% in the treated specimens and which future increased the unconfined compressive strength and split tensile strength. A reduction in the swelling pressure and swell strain is also observed. The results show that a cost-effect and eco-friendly method can be deployed for stabilizing the road pavement subgrades. The statistical assessment using multivariate analysis and hierarchical clustering dendrogram has been carried out to investigate the effect of the MICP treatment protocol on different soil and engineering parameters.

scholarly journals Characteristics of Mixed Porus Asphalt with Combination of LDPE, CPO and PEN 60/70

2021 ◽  
Vol 1 (4) ◽  
pp. 19-24
Author(s):  
Meidia Refiyanni ◽  
Chaira Chaira
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Mixture ◽  
Test Results ◽  
Porous Asphalt ◽  
The Road ◽  
Road Pavement ◽  
Asphalt Content ◽  
Poly Ethylene ◽  
The Second Variation

The quality of the road depends on the pavement, drainage conditions, and materials. For this reason, it is necessary to make innovations in improving the quality of road pavement, one of which is increasing the material. There are many types of pavements, one of which is porous asphalt pavement. Porous asphalt has many cavities that is easy for water to pass but has a low stability value with high           permeability. This research will utilize Low Density Poly Ethylene (LDPE), as an additive, CPO, and Pen 60/70 in a porous asphalt mixture. The purpose of this study was to determine the characteristics of the porous asphalt mixture by substituting LDPE and CPO for Pen 60/70. The method used in analyzing the characteristics of the porous asphalt mixture refers to the specifications of the Australis Asphalt Pavement Association (AAPA) (2014), with parameters Camtabro Loss (CL), Asphalt Flow Down (AFD), VIM, stability and flow. The gradation used in this study is an open gradation. This research was started from determining the value of Optimum Asphalt Content (KAO), with two variations, namely Variation 1 (1% LDPE, 10% CPO, 89% pen 60/70), variation 2 (5% LDPE, 10% CPO, 85% Pens 60/70). The KAO value of variation 1 is 5.03% and the second variation is 4.75%. After obtaining the KAO value, LDPE and CPO are substituted. The test results for the porous asphalt mixture for CL values were 34.12% and 27.07%, respectively; AFD value of 0.13% and 0.12%; for the VIM value of 14.90% and 19.03%; stability value 603.24 kg and 603.19 kg; and flow values are 5.03 mm and 4.80 mm. In general, the value obtained from the test meets the required requirements. However, the durability value of the mixture did not meet the requirements, namely 60.15% and 48.22%, with the condition >90%.

scholarly journals Analysis of Technical Condition of Local Roads Drainage in the Czestochowa Region

2019 ◽  
Vol 1 (1) ◽  
pp. 251-260
Author(s):  
Zbigniew Respondek
Keyword(s):  
Rural Areas ◽  
Technical Condition ◽  
Rapid Loss ◽  
Rural Municipality ◽  
The Road ◽  
Road Pavement ◽  
Local Roads ◽  
Drainage Problem

Abstract Local roads (district and municipal) play an important role in the road network, especially in rural areas. In recent years, these roads have been largely repaired, which was often associated with the construction of new infrastructure. One of the basic conditions of maintaining the quality of road works is the proper construction or renewal of drainage devices. Errors in this area result in lower durability of the road pavement. It is equally important to maintain these devices later in a good technical condition, which requires spending appropriate funds from local government budgets. The aim of the study presented in the article was to determine the current technical condition of drainage of local roads in the Czestochowa region and to identify the most frequent design and implementation errors, resulting in a rapid loss of functionality of drainage devices. They were based mainly on in situ studies carried out in the area of an exemplary rural municipality. Errors resulting in the lack of continuity of drainage, or the danger of a rapid loss of its functionality are shown with real examples. It was found that despite the shortcomings described, in recent years the technical condition of drainage of local roads has improved, which is related to the systematic overhaul of local roads (including the construction of sidewalks) and the local government's perception of the importance of road drainage problem.

Estimation of Subgrade Soils Resilient Modulus from in-situ Devices Test Results

2009 ◽  
Vol 37 (3) ◽  
pp. 101993 ◽  
Author(s):  
M. R. Mitchell ◽  
R. E. Link ◽  
Louay N. Mohammad ◽  
Munir D. Nazzal ◽  
Murad Y. Abu-Farsakh ◽  
...  
Keyword(s):  
Resilient Modulus ◽  
Test Results ◽  
Subgrade Soils

Moisture-Density Relationship of Bottom Ash, Lime Stabilized Bangkok Clay as a Potential Pavement Material in Thailand

2019 ◽  
Vol 972 ◽  
pp. 50-56
Author(s):  
Akanksha Bhurtel ◽  
Amin Eisazadeh
Keyword(s):  
Clayey Soil ◽  
Bottom Ash ◽  
Dry Density ◽  
Test Results ◽  
Maximum Dry Density ◽  
Water Contact ◽  
The Road ◽  
Density Relationship ◽  
Relationship Of ◽  
Pavement Material

Expansive clayey soils like Bangkok clay can shrink and swell with water contact. Therefore, the presence of such soils tends to damage the road conditions with a higher frequency of rainfall in Thailand. The presence of expansive clayey soil has brought the concept of stabilization of such roads with any other stronger materials. This paper shows the test results on the moisture-density relationship of bottom ash and lime stabilized Clayey soil to use as a pavement material in Thailand. In this study, a waste material produced from coal combustion called bottom ash was used as a replacement material and quicklime as a binding material. During the tests 10%, 20%, 30% and 50% bottom ash and 4%, 8%,12% Lime were used. The result shows a decrease in Maximum Dry Density and increase in Optimum Moisture Content with an increase in each amount of replacement material.

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