Showing papers in "International journal of GEOMATE : geotechnique, construction materials and environment in 2015"

Performance of automatic control different localized irrigation systems and lateral lengths for : 1-emitters clogging and maize (zea mays l.) growth and yield

Abstract: Many parts of the world including Egypt currently suffer from water scarcity. For this reason optimization of the available water has become a necessity not only from the point of limited water resources, but also relative to the growing demand for food. Field experiments were conducted at Experimental Farm of National Research Center, El-Nubaria, El-Buhaira Governorate, Western Delta, Egypt to study the effect of automatic control of the localized irrigation system(LIS) as a modified system on emitter's clogging and maize parameters in new reclaimed lands by using the following treatments: a) Bubbler irrigation systems (B); b) Low head drip irrigation system (LHD), and c) Mini-sprinkler irrigation system (MS) through different lateral lengths (40, 50; 60m). Plants were irrigated every 4 days to compensate ETc and salt leaching requirement took place. The obtained data showed that emitter's clogging percentage could be ranked in the ascending orders: LHD

Lime leachability studies on stabilized expansive semi-arid soil

Abstract: The present study is aimed at examining the role of lime and the nature of leaching solution on the lime leaching characteristics of an expansive soil originating from the Kingdom of Saudi Arabia. Lime leachability studies were carried out in specially fabricated molds subjected to continuous leaching conditions. The specimens were compacted directly into specially fabricated perspex molds and cured for 7, 14 and 28 days under constant humidity conditions. In order to study the rate at which the calcium ions leach out from the lime treated clay matrix, water (leaching solution) was allowed to flow through the compacted specimen continuously for seven days and the resultant calcium concentration in the leachate was determined. The effects of various parameters like lime content, curing period and the pH of leaching solution on the lime leachability values has been studied. It is observed that, at a given lime content, the calcium concentration in the leachate reduces with curing period. Relatively higher amounts of lime leached under acidic conditions and the flow period does not affect the lime leaching patterns.

Engineering properties of black cotton soil-dolime mix for its use as subbase material in pavements

Abstract: In this paper, an attempt is made to stabilize problematic expansive Black Cotton (BC) soil by dolime fines for its use in subbase course of flexible pavements. Atterberg limits, free swell index, compaction characteristics, unconfined compressive strength (UCS), soaked CBR, shear strength parameters and resilient modulus are evaluated for different trial mixes cured up to 28 days. BC soil stabilized with a minimum dolime content of 9% satisfies the criteria recommended by Indian Road Congress for utilization in subbase layer of flexible pavements. The effects of dolime content and curing period on the above geotechnical properties of the mixes were investigated. Empirical relationships are developed to estimate important design parameters such as deviator stress at failure and cohesion of the stabilized mix that can be used to determine dolime content to achieve a target strength within a given curing period. Different empirical models are proposed to estimate the resilient modulus of soil-dolime mixes and their performances for the prediction of resilient modulus are compared.

Impact of bubbler discharge and irrigation water quantity on 1- hydraulic performance evaluation and maize biomass yield

Abstract: The aim of current research work is studying the effect of two bubbler irrigation discharges (BD) were: a) 8 LPH and b) 12 LPH, and different water quantity treatments from evapotranspiration (ET): 100%, 75%, 50% on uniformity coefficient (UC%), emission uniformity (EU%) and coefficient of variation (CV%), maize (Zea mays-L., HF-10 Varity) grain and Hay yield. The experiment design is split in randomized complete block with three replicates. So, field experiment for one growing season (2014) was conducted in sandy soil at the Agricultural Research and Production Station of National Research Centre, El- Nubaria, Elbehira Governorate, Egypt. Irrigation water was added in order to compensate for ET of maize. Obtained data could be summarized as follow: Parameters under study could be ranked in following descending orders: 8 LPH>12 LPH and 100>75>50 for bubbler discharge treatments, except for CV%. Investigated bubbler discharge (8 and 12 LPH), increase operating pressure head, getting improvement in UC%, EU% and decreasing CV values. With respect to BD and ET% effect on UC, EU%, maize hay yield, and significant difference at the 1 % level between all mean values of bubblers and ET% treatments were obtained. The interaction effects of the investigated factors, the highest and lowest values of maize hay yield were recorded under 8 LPH X 100% and 12 LPH X 50% ET treatments. These attained results were attributed to the improvement in hydraulic parameters of UC%, EU% and CV Also the Irrigation treatments of 100 and 75% from ET were covered water requirements and also recorded convergent results in values which means that the quantity of water added (which is the difference between the 100-75% =25% ET). It's amount, in excess of the plant required under the current conditions of the experiment. So it can be recommended to using 75% for saving 25% from water requirements under bubbler irrigation system using 8 LPH bubbler.

Determination of the freezing effect on unconfined compression strength and permeability of saturated granular soils

Abstract: Artificial ground freezing usage gradually rises in civil engineering applications as a soil supporting system However, many unknown fundamental parameters have been still waiting discovery, especially for granular soil Granular soil can not carry its own weight during unconfined conditions If water turns to ice that locates in the soil pores, it proceeds as a cementitious material First step of design phenomena is to identify the material properties in geotechnical engineering Within this scope, unconfined compression tests (UCC) and permeability tests are performed on frozen granular soils subjected to 1, 3 and 7 day-freezing periods to observe time effect Experimental procedure are applied totally on 12 sand and gravel type of specimens with saturated cases after freezing application in the CDF/CIF freezing thawing machine Stress - strain behaviors, ultimate load capacities and permeability of specimens are determined This method will be used while taking undisturbed granular soil samples from the construction site

Ecological significance of masonry revetments in plant biodiversity

Abstract: The objective of this research is to evaluate the importance of vegetation of retaining walls made of natural stones (i.e., masonry revetment) in plant biodiversity. In this paper, plant compositions and the characteristics of masonry revetments were surveyed in terraced fields in Toho Village, southern Japan. In total, 43 families and 88 species were recorded in the spaces of the masonry revetments. Of these 88 species, 68 (77.3%) were herbaceous, excluding 13 (14.8%) ferns, and 7 (8.0%) species were woody plants. Native species accounted for 69 (78.4%) of the 88 species. Furthermore, numerous species not found in the horizontal environments around the terraced fields were also seen in the spaces of the masonry revetments. From these results, the authors consider that masonry revetments provide a habitat for plants and therefore contribute toward the conservation of plant biodiversity on a local scale.

Developing a decision-making model for reinforced concrete columns strengthening

Abstract: Steel tubes (ST) have long been used to strengthen RC columns, while the application of CFRP for this purpose is a recent practice. Both techniques have many advantages and shortcomings. In this paper, a multi-criteria decision-making model is introduced to quantify the selection of one of the two techniques. Four criteria and 28 factors affecting them are identified to develop the model. The selected criteria are cost, strengthening efficiency, durability, and project scope achievement. The model is fed by data collected from execution activities, field surveys and previous laboratory test results. The model hasbeen validated and applied to a real case study. The detailed discussion and analysis indicated that many features support the use of CFRP in the investigated case study. Furthermore, the analysis emphasised that the strengthening efficiency and durability decide the selection while project scope achievement criterion isinsignificant compared to other criteria. Ultimately, the obtained results from the case study provide the construction market with a decision that supports the use of the CFRP by 56 %, while the use of ST is only supported in 44 %.

Pore water pressure generation and dissipation near to pile and far-field in liquefiable soils

Abstract: The degree of liquefaction as characterised by the excess pore water pressure plays an important role in defining soil strength and stiffness. The pile-soil interaction in liquefiable soil, if modelled using BNWF model, the strength and stiffness of the soil springs can be suitably reduced by using a reduction factor. This reduction mainly depends on the soil type, its SPT/CPT value and the degree of liquefaction. Ideally this reduction should be based on the excess pore water pressure near the pile. However, it is difficult to estimate the degree of liquefaction near the pile. Hence, the lateral resistance of liquefied soil at soil-pile interface is normally characterized by the degree of liquefaction expected in the soil at the site without considering the influence of pile. Though, excess pore pressure near to the pile could be the governing parameter of soil resistance, it is hard to characterize the expected value of it in a field condition, as it depends on many parameters including soil type, shear loading, pile dimension, gap formation near to pile that facilitates easy dissipation of excess pore water pressure (EPWP), soil densification during pile driving, etc. Hence, to understand the difference between the far- field and near-pile response of liquefied soil, one high quality centrifuge test results are studied in this paper. The pattern of excess pore water pressure generation and development has been compared for both near-pile and far- field. The results are critically reviewed and discussed in this paper.

Water balance analysis considering runoff of ungauged catchments in iwaki river basin, northern japan

Abstract: For integrated and sustainable water resource management, it is essential to understand water balance of river basin Infiltration calculated by subtracting evapotranspiration and runoff from precipitation is a key factor for groundwater resource development and is an important input data for three-dimensional groundwater flow analysis For estimation of runoff, it needs a great challenge to establish a method for runoff in ungauged catchments, because gauging stations are usually set up in the limited main rivers This paper focused on close relation between topography and runoff Then, the runoff of ungauged catchments in the Iwaki River Basin was estimated by "runoff index" derived from results of geomorphometry and multivariate statistics using digital elevation model data Comparisons between runoff indices and measured runoff data, showed clear positive correlations This result proved that runoff index was useful for runoff estimation, and suggested that it was possible to estimate runoff of ungauged catchments from runoff index by linear regression equation

Consumption of rainwater harvesting in terms of water quality

Abstract: Rainwater harvesting is seen as part of solution to avoid water shortage in the future as it offers a sufficient supply and more economical if compare to the conventional way. The scarcity of water supply is becoming a concern due to the growing population of human along with environment pollutions. Rainwater harvesting is considered the most accessible source which could be easily used for potable purposes both for household and commercial activities. Therefore, in this study, the physical, microbiological and chemical rainwater quality samples were analyzed using membrane filtration technique (ELE Paqualab 50), ICP-OES and Hach methods, to ensure the suitability of rainwater harvesting for domestic consumption. The study reveals that overall quality of the rainwater is quite satisfactory as per WHO and Malaysian standards, where the pH, turbidity, total dissolved solids, salinity, NO3- , SO4 2- , Zn and Pb were still under the permissible limits. However, the microbiological parameters (total coliform, fecal coliform and E. coli) and chemical (Cr) were found exceeded the standards, due to poor hygienic practices of the harvesting system. It can be concluded that the rainwater harvesting is still safe to drink and can be a potential alternative source of water supply in the future.

A behavioural study of dynamic soil structure interaction for piled raft foundation with variable sub soils by time history fem model

Abstract: India is the developing country and in this age of rapid urbanization, geotechnical issues in construction of tall buildings are a major problem. These act as strong barriers against the construction of tall buildings in urban areas. Piled raft foundation is the type of foundation which can be used for the construction of tall buildings safely and economically. The piled raft foundation system has recently been widely used for many structures, especially high rise buildings. In this foundation, the piles play an important role in settlement and differential settlement reduction, and thus can lead to economical design without compromising the safety of the structure. Foundation rafts are analyzed as a plate on elastic foundation with the representation of the foundation media using the Winkler idealization. The elastic constant of the Winkler springs is derived using the sub-grade modulus. Perusal of literature reveals that very few investigations were done on the effect of variable sub soil on the behavior of structures supported on pile raft foundations. So in this research, an iterative dynamic analysis was performed using SAP2000 program to carry out three dimensional time history analysis of non-linear soil-foundation-building models under a great earthquake ground motions. The interaction between the soil and structure is represented by Winkler spring model. The obtained results confirmed that the dynamic characteristics of soil structure system should be recommended for conservative nonlinear seismic response of the high building since it mitigates of earthquake hazards.

Small water distribution system disinfection by-product control : water quality management using storage systems

Abstract: Disinfection, a vital part of a drinking water treatment, using chlorine is the most widely practiced process in the world. The Stage-2 Disinfectant and Disinfection By-Product regulations force water utilities in the US to be more concerned with their distributed water quality. Compliance requires changes to their current operational strategy. Storage system management is an important part of the operational strategy of small scale utilities. This study quantifies changes in DBP formation and chlorine decay in storage systems under varying operational parameters such as mixing, contact time, and water movement using a physical model (Pipe Loop) of a distribution system. Effective operation of storage systems can yield greater than 30% decrease in DBP formation in distribution systems and maintain chlorine residual for a 50% longer period.

Cu, zn and as contamination of seaweed beside shizuki and kanayama metal mines in japan

Abstract: Brown seaweed, Sargassum thunbergii is thought to be effective for As, Cu and Zn sensor. Green seaweed, Ulvales, red seaweed, Caulacanthus ustulatus and Ahnfeltiopsis flabelliformis are thought to be effective for just Cu sensor. High Zn concentration and large volume of Zn drainage water from the closed Kanayama mine flowed into sea and drainage water and groundwater containing Cu, Zn and As contacted with muck along the coast also flowed into sea in the closed Shizuki mine. Cu, Zn and As concentrations for many kinds of seaweed sampled at the two mines and no contamination places, the Kii and Izu Peninsula, were measured. Cu Zn and As concentrations for Sargassum thunbergii are 1000, several 100 and several 100 ppm at the Shizuki mine and 10, several 1000 and 100 ppm at the Kanayama mine, and 10, several 10 and 100 ppm at the no contamination places.

Numerical analysis on the effect of jet grout piles on an excavation located in an urban area

Abstract: The development of infrastructure in limited land space is a challenging scenario. Infrastructure in limited land space regions (e.g. Singapore) does not provide freedom to develop at favourable locations instead forces the engineer to design at the possible locations. Clay with high organic content, commonly referred as Peaty clay is predominant in coastal areas. This clay being highly acidic (PH>7) and possessing very low shear strength is a critical factor to the design of infrastructure in the vicinity. Ground improvement adopted weak strata will have varying effect and may not be able to achieve the required strength. This paper discusses the effect of ground improvement (Jet Grout Piles) on the sloped excavation predominantly in Peaty clay. A 15m deep excavation which is 60 m wide is used for the Finite element modeling. Impact study on a tunnel located 40m from the excavation is presented (The study is carried out for various achieved Jet grout piles strengths of 100, 200, 300, 400 and 500 kPa). The stability of the slopes for the various strengths is also discussed (GeoSlope was used as the medium to perform the geotechnical analysis).

Influence of fertilization on native plants and exotic pasture grasses on the fascined landslide slopes in mikura-jima island, japan

Abstract: Typhoon 9512 hit Mikura-jima Island, Izu Islands, Japan in 1995, producing many landslide slopes. Torino-o No.3 landslide slope was fascined with fallen trees and planted with seedlings of native species (Alnus sieboldiana tree and Miscanthus condensatus grass) as part of vegetation recovery efforts, and was subsequently seeded by helicopter in 2002 with exotic pasture grasses. To elucidate the influence of fertilization on the growth of transplanted seedlings of native species, exotic pasture grasses and newly invading trees and herbs, we designated seven plots in 2004, and surveyed vegetation every summer until 2013: four fertilized plots (fowl manure applied at 0.2 g/m 2 ) and three non-fertilized plots. The native species seedlings grew steadily irrespective of fertilization, but with self-thinning in A. sieboldiana. Exotic pasture grasses decreased gradually and almost disappeared in 2013. Fertilizing temporarily enhanced the growth of some species, but seemed to induce species competition, judging from the delay of invading of native trees and the increase of climbing plants in herbaceous layer in fertilized plots.

Determination of slip surfaces in fracture zone landslides using oriented borehole core samples

Abstract: In situ and laboratory observation, geophysical measurement and digital imaging analysis of oriented borehole core samples are performed to determine slip surfaces in two large fracture zone landslides in Shikoku, Japan. The following data are obtained from each oriented borehole: (1) a depth distribution of rock quality designation, magnetic susceptibilities, the Equotip hardness values and wet unit weight of core samples, (2) geometric orientation of geologic discontinuities (cracks, joints, faults, etc.), and (3) a depth distribution of numerical color values from digital imaging of borehole core samples. As a result, the rock quality designation, the Equotip hardness value and unit weight, and the orientation of cracks and joints showed a clear change near the slip surfaces respectively, but the digital color values clearly varied only in one of the landslides and no change of magnetic susceptibility of core samples was found at both sites. The results demonstrate that it is capable of locating the slip surface in a fracture zone landslide by using the above-mentioned data in combination.

The role of block ratio and layer thickness on rock slopes movement style

Abstract: ABSTARCT: In rock slopes, toppling movements are very common. The layers thicknesses and block ratio relative to slopes height might determine the type of slope movements and the style of toppling. In this paper, a numerical parametric study was conducted to evaluate the effect of block ratio and block thickness, in both crystalline and sedimentary rock formations, on the style of rock slopes movement in slopes prone to toppling. The mechanical defects or joints of rocks can be either random or well defined sets depends on the rock mass origin, metamorphic, igneous, or sedimentary. Different styles of movements were observed numerically in this study ranging from block toppling to rock falls. The styles of movement were also compared to the ones observed in the field. The results showed that the style movement is time dependent and three types of movement can be observed in one slope.

Hydraulic conductivity in loessic stabilized soil

Abstract: Loessic soils are the main geological storage available as a building material in Cordoba, Argentina. They are a typically kind of clayed silty soil with a metastable structure. Their structure makes them sensitive to collapse and sliding upon wetting. This has an important influence on mechanical and hydraulic behavior. Thus, usually their hydraulic properties are modified by compaction methods or by bentonite addition. Infiltration tests were done using remolded samples and a flexible wall permeameter. Compression tests were executed in a universal compression machine. Were performed in addition, capillary rise assays. Water content, dry unit weight, and percentages of ionic stabilizer and bentonite have been studied. Experiment results were compared between mixtures with different percentages of additives. The results show that the infiltration volume decreases with increasing content of bentonite in all remoulded samples tested respect to those natural soil remoulded samples, and it has been identified that the addition of bentonite increases the compressive strength by 400%.

Comparative analysis of three embankment methods for road construction by life cycle assessment and cost

Abstract: In recent years, new composite geomaterials have been developed to reduce the weight of road construction materials in soft ground and mountainous areas in Japan that are prone to ground liquefaction and landslide. These new composite geomaterials have some problems, such as increased construction time, cost, and adverse impacts on the environment. As a result, conventional geomaterials are usually chosen over composite geomaterials in Japan. However, there are few researches that analyzed the environmental impacts (for example, CO2, NOx, and SOx emissions as well as total life-cycle cost) of traditional and composite geomaterials quantitatively from the perspective of LCA (life cycle assessment). Therefore, the purpose of this research is to apply a LCA to estimate the total emissions of CO2, NOx, and SOx as well as the total life cycle costs of three embankments—one constructed by the conventional method (cut and fill), one with lightweight geomaterial mixed with expanded polystyrene beads, and one by the expanded polystyrol construction method. All three embankments are located on a mountain road in Japan.

Study on the use of obstructing objects to diffuse flood water velocity during road crossing

Abstract: Laboratory experimental investigations were conducted to identify suitable shape and dimension of objects as well as its capability to reduce flow velocity The first stage of the study was to identify suitable shape and its arrangement In this test a scale of 1:20 was used in a flow table experiment The water flow pattern was recorded focusing on the distance and amplitude of the pattern as water flow pass the obstructing objects The second stage of the investigation involved a hydraulic model investigation In this investigation, the velocity reduction effects of the selected objects shapes were studied The results are classified into three distinguishable patterns of diffusion Two objects shapes and arrangements selected for use in the hydraulic model investigation indicated its capability to reduce flow velocity satisfactorily consistent with the flow pattern in the preliminary findings

Correlating bender element and electromagnetic measurements to evaluate clay's stiffness

Abstract: Soil's stiffness is usually measured in the laboratory in an indirect manner, such as by derivation from the gradient of a stress-strain plot. It requires numerous tests and may be compounded by errors from the original measurement itself. As such, the bender element test has become rather popular among researchers for determining the small strain moduli of soils with minimal / temporal disturbance to the specimens. This paper examines the possibility of relating the bender element data with the dielectric constant obtained from the same soil specimen using an electromagnetic test setup. As both tests are non- destructive, they can be easily repeated on the same specimen over a period of time without the necessity of duplicate specimens. A clay sample was used in the present study, with varying water content corresponding to different 1-dimensional compression stresses. It was generally found that the resulting stiffness change was detectable from both the shear wave velocity (vs) obtained from the bender element tests, as well as the dielectric constant (e) of the electromagnetic measurements, with fairly good correspondence between the two. These results shed light on the possibility of relating relevant geotechnical parameters with both the measurements for establishing a unique set of signatures for stiffness monitoring and determination in soils.

Wood-tile quality composite board from coco coir dust and unplasticized polyvinyl chloride waste materials

Abstract: Gearing on sustainable technology, two waste materials, coco coir dust and UPVC were utilized to produce a wood-tile quality, high density composite board material. Adopting the technology in producing fiberboards, the use of UPVC as binder to combine with dried coir dust (5% moisture content) was investigated. Three mix ratios of UPVC: Coir Dust were used: 80:20, 70:30 and 60:40. The produced board from each combination was then subjected to mechanical and physical property tests. Their properties were compared using the analysis of variance. The mixing process involves the use of two -roll mill machine operating at 204 O C while the pressing involves the heat press machine at 108 O C and pressure of 450 psi for 3minutes. The finished products highlight a glossy brown surface comparable to a wood tile, and can be readily manufactured without the additional veneer coating. Physical properties of the 3 ratios were tested against ordinary board. All 3 ratios exhibit 0% Water Absorption (WA) and Thickness Swelling (TS) while ordinary board showed 28.5% WA and 16.5% TS. Mechanical tests for the 80:20 ratio yielded a highest mean value of 55KPa·m on Impact Strength (IS) and 68.85MPa on Modulus of Rupture (MOR) while ordinary boards yielded 50KPa·m on IS and 7.51MPa on MOR. The least mean on different properties of the bio-composite material were compared with the means of commercial board product. This study found that the PVC-Coir Dust combination exhibited highly satisfactory performance based on the physical and mechanical properties as compared to the ordinary board.

Landfill waste warter treatment by application of pulsed high voltage

Abstract: In this study, using the plasma generated from the pulsed discharge process, we examined the possibility of simultaneous degradations of dye substance and COD component in the landfill waste water. Furthermore, the possibility of sterilization by the plasma was investigated in the experiments. Experiments were performed to investigate the effects of voltage, repetition rate, charging time and O2 coexistence on the sterilization and degradations of COD and dye substance. The experimental results show that the sterilization and simultaneous degradations of the dye substance and COD are possible by the plasma and the dye substance is easily decomposed by the plasma from COD. The degradations of the dye substance and COD were enhanced by the presence of O2, while the effect on the dye substance degradation is larger than COD degradation. The results reveal that sterilization is possible by plasma, and E. coli is completely dead as compared with the bacteria is difficult to kill completely by the plasma.

Uptake of advanced and sustainable engineering materials in civil infrastructure projects

Abstract: Advanced and sustainable engineering materials, such as engineered fibre composites, geoploymer cement, and recycled concrete have the potential to reduce demand on scarce resources, improve safety, reduce greenhouse gas emissions and contribute to positive initiatives in civil engineering design and construction in areas like foundations and structural members. For example, engineered fibre composites can replace other materials (such as timber), because of their high strength to weight ratio, light weight and ease of installation. They can also have positive impacts on sustainability. While advanced materials have several advantages, their take-up by industry, and in particular small and medium enterprise companies (SMEs), has in a number of cases been relatively slow. This is likely to be the result of a number of factors, such as relatively high cost, financial risk in using an unproven technology, lack of suitable design standards, an unproven life cycle, uncertainty over long-term sustainability issues, and possible changed building and construction methods. Advantages and disadvantages of the use of selected advanced and sustainable materials in civil engineering projects are investigated. A weighted scoring methodology for improved evaluation of their advantages and disadvantages, with a view to aiding decisions, is proposed.

Understanding to predict soil behavior

Abstract: Understanding is needed to relate variation of shear strength of soil in different environment. The shear strength is determined by the parent material of the soil (mineral skeleton), pore fluid (distilled water/ saline water) and environment which changes from land areas to deep Ocean. The shear strength interpretation is extended to the environments of turbidity currents, carbonate compensation depth and abyssal plains. The abyssal plains maintain moderate shear strength. The abyssal plain is a controlled environment which controls any events of the restless earth around it. The Carbonate compensation depth influences both turbidity currents and abyssal plains. Based on the analysis and interpretation of documented cases this paper makes a new conceptual model in interpretation of the influence of Carbonate Compensation depth on turbidity currents in Abyssal plain and the geotechnical behavior of the sediments in Abyssal plains. Documented Cases are: 1) Liquid Limit of a soil calculated by using distilled water is not representative sample in marine condition. The distilled water overestimates Geotechnical property. 2) The failure envelope of reconstituted clay mixed with distilled water is different from the one mixed with Nacl solution. 3) The Oedometer test on undisturbed specimens exposed to distilled water display higher strains than tested in solution.

Rehabilitation works in queensland using foamed bituminous stabilisation

Abstract: Adapting foamed bitumen stabilisation is considered as the most cost effective approach in Queensland to expedite the rehabilitation works, especially after the major flood devastation in 2011 This paper presents the key changes made as well as the recent practices adapted during a road rehabilitation work to increase the return from the investment In this process, initially, the designed width for subgrade lime stabilisation has been modified to minimize the moisture entry into the pavement The dry modulus, three days soaked resilient modulus and retain modulus were used to identify the suitable base material for construction In addition, a trail site was used to examine the bulking effect on base layer when adding lime as secondary agent, which helped to estimate the exact depth for foamed stabilisation A few innovative techniques such as a two-layer compaction to effectively condense stabilised subgrade, was used to improve the quality of the outcome were also highlighted