Civil Engineering Works Research Articles

Reducing the carbon footprint of municipal infrastructures

Developers of municipal infrastructures have focused so far mainly on the operation of infrastructure networks (e.g. roads) or facilities (e.g. district heating facilities) and their impacts on climate change. Only recently, the focus shifts to optimizing CO2 emissions embodied in building materials and caused by processes and transports related to construction, maintenance, overhaul and renewal of civil engineering works. The European standard EN 15643-5:2017 provides specific principles and requirements for the assessment of their environmental performance and a new standard for calculation methods will be published in 2022 including an assessment of embodied C02 emissions. But, how can this information be used to systematically reduce the carbon footprint for municipal infrastructures? In an ongoing research project, we want to answer this question and develop a management cycle for optimizing the carbon footprint of municipal infrastructures. In a first step, we used expert interviews with infrastructure operators, planers and builders focusing on roads to define use cases where information on embodied CO2 emissions is needed. In a second step, we studied construction projects (completed in the past) to analyze data availability at different stages of the planning process. Based on our preliminary results, a management cycle should include the following four use cases for using information on embodied CO2 emissions for decision support. First, it should be used for monitoring of infrastructure networks (as part of scope 3 accounting for operators). Second, it supports priority setting for renewal and overhaul planning when used to analyse representative project portfolios. And, it will help developing project specific benchmarks for optimization at early design stages as well as before public tender. In the next step of our project, we will adapt existing calculation methods in collaboration with operators of municipal road networks to meet information requirements in the identified use cases.

Experimental investigation of crude oil contaminated soil for sustainable concrete production

Contaminated soil materials are often unsuitable for engineering construction works due to high content of impurities which inhibits development of mechanical strength and durability properties. This study was therefore necessary to make available empirical evidence revealing the consequences of crude petroleum pollution on the mechanical characteristics of materials made of concrete and determine its effect on civil engineering works. The study involved collection of contaminated soil sample from the Kolomani oil-well in Bauchi State, Nigeria and laboratory evaluation performed to evaluate the engineering possessions of concrete formed from contaminated soil sample. A calculated ingredient at a proportion of water to cement (W/C) set at 0.5, a mix proportion of 1:1.8:2.7 was used with the fine aggregate content replaced partially with crude oil contaminated soil materials (COCM) from 0–40%. The obtained laboratory results showed rise in compressive strength property as COCM fraction increases with the optimal response of 16.36 N/mm2 derived at 20% replacement. The experimental results was further subjected to statistical analysis using one-way ANOVA and F-statistics to test the source of variation for the geotechnical properties. Multiple Linear Regression (MLR) and correlation statistics were then used to establish relationship between mix ratios and the geotechnical properties. The results signifies good performance with R-squared of 82.81. The benefits derived from this work would enhance production of sustainable concrete works which can be applicable in large scale for tile production.

Chloride Ingress Resistance, Microstructure and Mechanical Properties of Lightweight Mortars with Natural Cork and Expanded Clay Prepared Using Sustainable Blended Cements

The use of lightweight aggregates in construction materials is a good solution for increasing the contribution to sustainability of civil engineering works, such as maritime ones. In this regard, the possibility of using cork granulates and expanded clay is a current research topic. The combination of eco-friendly cements with lightweight aggregates could provide solutions for developing new building materials. In this work, it has been studied mortars prepared with sustainable cements and the lightweight aggregates of natural cork and expanded clay. These cements incorporated slag, limestone and fly ash. Reference mortars with only sand as aggregate were also made. The total porosity and pore size distributions were obtained. The non-steady-state chloride migration coefficient and compressive and flexural strengths were also determined. The tests were performed at 28 days and 1 year. The differences in the total porosity between the natural cork and expanded clay series were not high, depending on the binder. Natural cork mortars showed similar or slightly higher migration coefficients than the reference and expanded clay mortars at 1 year. This adequate chloride resistance and the low mechanical strengths observed for the natural cork mortars recommend the possible use of this new aggregate in non-structural cement-based materials for civil engineering works exposed to maritime environments.

Investigating the Potential of Infrared Thermography to Inform on Physical and Mechanical Properties of Soils for Geotechnical Engineering

Knowledge of physical and mechanical properties of geomaterials is fundamental to characterise their response to external forcings (mechanical, climatic) at various scales. This is true, for instance, in slope stability assessments, civil engineering works, and agriculture. The direct evaluation of these properties in situ can be difficult, especially in inaccessible or vast areas, and so can be the sampling and subsequent testing in the laboratory—where ensuring the representativeness of the acquired data at the scale of analysis poses an additional challenge. Thus, empirical correlations with more readily determinable quantities remain a powerful and practical tool. Recently, several sensors, able to inform on various geomaterial properties, have been developed. However, applications have typically targeted rocks, while studies on uncemented geomaterials (soils, geotechnically speaking) are lacking. Here, we propose a simple method to evaluate the porosity and critical state friction angle of soils via infrared thermography, consisting of periodic acquisitions of images in infrared wavelengths. To demonstrate the method’s capability, we analysed the cooling behaviour of samples of bentonite, kaolin, and sand (for which an extensive characterisation exists in the literature), after compaction to different porosities and pre-heating in an oven. We interpreted the results by seeking the optimal time interval for which a cooling rate index (CRI) could be defined, which is best linked with the target property. We found that the CRI correlates very well with the critical state friction angle (R2 > 0.85) and that different materials show unique and strong (R2 = 0.86–0.99) relationships between their porosity and the CRI, which also varies in a material-specific fashion according to the explored time interval. Although a systematic investigation on a wide range of natural soils is warranted, we argue that our method can be highly informative and could be used to calibrate remote sensing-based full-scale implementations in situ for various purposes.

Characterization of In Situ Concrete of Existing RC Constructions

The strengths and mechanical characteristics of concrete play a key role in the safety levels for the recovery and reuse of existing RC buildings and civil engineering works. This is one of the main focuses of the current research trend. To this aim, the characteristics of concrete must be investigated: the characterization of the concrete and its in situ conditions play a key role. For these reasons, many studies on in situ and laboratory test methods and procedures have been carried out over the last two decades. In the past few years, non-destructive investigation methods have been considered reliable and used in many engineering applications, also for RC constructions. More recent codes and guidelines identify destructive test methods as a reference for practice application. However, non-destructive investigation methods can be used though exclusively in combination with destructive tests to support them. In this study, a significant database is considered to assess the reliability of the relationship between destructive and non-destructive methods for in situ concrete in existing RC constructions. The results of the analyses are used to verify the effectiveness of the methods and prediction models and suggest more effective test procedures. It can be stated that many of the existing empirical methods (based on pre-established correlations) are unable to provide a reliable evaluation of the compressive concrete strength and its variability. In practical applications, non-destructive methods often lead to unsatisfactory results for the existing reinforced concrete constructions. Finally, based on the results, some first operational indications are provided for practical investigations and future possible codes and guideline improvements.

Ground improvement by jet grouting and injection to control hydraulic conditions in the frame of Grand Paris Express Project, North-East section: methodology and quality control sequence

The main tunnels of Line 16 Lot1 of the Grand Paris Express project are underway since 2019 using tunnel boring machines (TBM). They are drilled entirely in permeable strata (fine/silty sands, marls, and limestones) at a depth of 20÷30 m below the groundwater level. Groundwater inflow with high pressure is a major issue at the arrival/departure sections of the TBMs as well as during the excavation work of connection galleries between the main tunnels and maintenance or security shafts. Line 16 Lot1 is located under dense urban areas with the requirement of minimizing the drawdown of the groundwater and water inflow in civil engineering works; the purpose is to avoid excessive settlements on existing facilities and dissolution reactivation process of gypsum-rich strata. In order to minimize these risks, different types of ground improvement technics (jet grouting and cement mixture injection) have been applied, where jet grouting is used in fine sandy soil and cement mixture injection used in fissured marly-limestone. In addition, both technics of improvement have been associated on the same site. From a geotechnical point of view, the sands of Beauchamp are classified as coarse-grained soils (60% SM and 40% ML in the Unified soil Classification System ) and Marly-limestone of Saint-Ouen and deep Marls as fissured soft to medium-hard calcareous rock. This paper presents the geotechnical conditions, the ground improvement methodology and quality control during construction. The control sequence is performed by vertical and then horizontal drilling holes. The method of control work after excavation (horizontal control) allows to confirm the quality of the treatment blocks and specifically the bonding between the treatment block and the diaphragm wall.

Petrographic and Geotechnical Characterization of Granites from Karay (Eastern Chad) for Their Use in Civil Engineering

Chad is in need of huge amount of aggregates, the most used materials, for its building and road construction. It is necessary to evaluate the geotechnical properties of the different types of rock outcropping in this country. This paper is focused on the petrography and geotechnical characteristics of granites from Karay (East Chad) for their use in civil engineering. The study area is located in the eastern Chad at about 50 km south to the town of Oumhadjer. The rocks that outcrop there form an isolated relief within a vast expanse of sand forming an inselberg. This relief is made up of fine, medium to coarse grained monzogranite cropping out as blocks and slabs, exposed to surface conditions (temperatures, waters and winds) that sometime transformed the micas and feldspars into clay. Microscopic description of thin sections of rock shows that they display a medium grained texture and are composed of quartz (32.8%), alkali feldspar (24.7%), plagioclase (21.4%), biotite (10.4%), muscovite (6.8 %) and opaques (3.7%). The geotechnical data showed that aggregates from the above rocks display Los-Angeles coefficient varying between 20.50 and 39.70% with an average of 29.60% and a Microdeval coefficient of comprised between 6.9 and 12.6 % with an average of 9.4%. These results indicate that the study materials can be used for civil engineering works. The correlation between the petrographic and geotechnical results indicates that the size of the grains, their arrangement (texture) and the mineralogical composition of rocks influence the geotechnical behavior of the aggrgates.

Evaluation of Concrete by Non-destructive Ultrasonic Pulse Velocity Method

Concrete is a material whose properties depend on its initial formulation, its conditions of use, and its change over time depending on its environment and the different types of degradation that it is likely to undergo. Knowledge and monitoring of its various mechanical properties are therefore essential for the maintenance of civil engineering works. All of the concrete assessment methods, whether destructive or non-destructive, can then provide a valuable diagnosis to the operators of the structure. Depending on their precision, they can be used to easily detect an alteration in the characteristics of the materials, locate a damaged area, the extent of the damage, or even precisely quantify the evolution of this damage over time and predict future changes. This paper presents the Ultrasonic Pulse Velocity technique (UPV) which is used by many companies to assess the compressive strength of concrete in situ and which allows measuring the speed and attenuation of elastic waves. The influence of the reinforcements on the ultrasonic pulse velocity has been studied and this is in the case of reinforcement perpendicular and parallel to the direction of propagation. The influence of several factors affecting the UPV, whether related to the properties of concrete or otherwise, was mentioned. Indeed, the porosity, the water/Cement ratio, the micro-cracks, the state of saturation and the temperature of concrete are parameters which strongly influence the values of UPV.

Utilization of Geotextile in Civil Engineering Work's

Utilization of Geotextile in Civil Engineering Work's

Utilization of Geotextile in Civil Engineering Work's

Utilization of Geotextile in Civil Engineering Work's

Research on shear strength of geopolymer concrete by using fly ash

Cement is one of the most important construction material. Cement is a backbone of civil engineering work. Development of whole world depends upon increasing infrastructure. For which cement is very necessary. Manufacturing of cement produce huge amount of carbon di-oxide and other greenhouse gases which is hazardous to the environment causes pollution. Hence it is very necessary to develop alternative binding material instead of cement for construction. Many researchers contribute their work on replacement of cement in concrete.

Petrographic and Geotechnical Characterization of the Magmatic Formations from Hadjer El-Hamis and Dandi (Hadjer-Lamis Province, Chad) for Their Use in Civil Engineering

This paper deals with the magmatic rocks from Hadjer El-hamis and Dandi located in the Hadjer-Lamis Province (Chad). Indeed, Chad is actually engaged in several construction project and consequently needs a large quantity of good quality construction materials. The present study is in straight line with this logic and aims to determine the petrographic and geotechnical characteristics of the Hadjer Lamis rocks in order to define their use in civil engineering. In this area, rocks outcrop in the form of mounds displaying hexagonal, pentagonal and tetragonal prisms in Hadjer El-hamis, and as fractured blocks in Dandi. Petrographic analyses show that rocks from Hadjer El-hamis are rhyolite displaying porphyritic to locally glassy microlitic texture with mineralogical quatz, alkaline feldspar, pyroxene, biotite and opaque minerals. Rocks from Dandi granites (microgranite, porphyritic microgranite and granite) with massive structure and fine grained (microgranite), fine grained porphyritic micrograined and gritty texture composed of quartz, orthose, plagioclase, pyroxene, biotite and opaque minerals of variable proportions from one rock to another.             The geotechnical analyses carried out on the crushed masses of the sites of Hadjer El-hamis and Dandi concerned their physical and mechanical characteristics. Their physical characteristics show that their average specific density values are 2.40g/cm3 and 2.60g/cm3 and bulk density are 1.41g/cm 3 and 1.38 g/cm 3 respectively for Hadjer El-hamis and Dandi samples. The average values of flattening coefficients are respectively 12.19% and 10.6% for  Hadjer El-hamis and Dandi areas. The mechanical characteristics of the studied materials on the basis of average values show that building materials from Hadjer El-hamis resist better to wear than those from Dandi, This difference in mechanical properties is certainly due to the petrographic nature characterized respectively by volcanic rocks in Hadjer El-hamis and plutonic in Dandi. Regarding resistance to impact, the geotechnical material from these two areas show very close average values of Los-Angeles coefficient and dynamic fragmentation coefficient recommended for civil engineering works. It appears from this research work that the studied materials are recommended for civil engineering work except for the sample E6 which presents too high Micro-Deval and Los-Angeles coefficients thus requiring a preliminary treatment before use.

긍재(兢齋) 김득신(金得臣, 1754~1822) 생애의 재구성

Geungjae (兢齋) Kim Deuk-shin (金得臣, 1754~1822) was a painter from the Yeong, Jeong, and Sun Dynasties. Born to the Kaesong Kim clan, a noble painter family of the late Joseon Dynasty, he entered the Dohwaseo in his teens and, for more than 44 years, played critical roles of a major painter, living the typical life of a painter during the late Joseon Dynasty. In addition to his well-known genre painting, he was one of the best painters of his time, presenting outstanding skills in almost all genres, including landscapes, figures, furry animals and flowers and birds. Nevertheless, many viewed him with limited perspectives, such as “a painter whose major inspiration was Kim Hong-do” and “a painter only known for genre painting.” Focusing on these aspects, this paper intends to reconstruct Kim Deuk-shin’s life and his influence on Korean painting history.
 Born to the Gaesong Kim clan and Shinpyung Han clan, both noble painter families of the late Joseon Dynasty, Kim Deuk-shin received rigorous education from an early age and became an official Dohwaseo painter in his teenage years. After the establishment of Jabidaeryungw hawon (the best painters of their time, temporarily recruited for royal court assignments in the late Joseon period) by Gyujanggak, he was recruited as one of the first Jabidaeryungwhawon and devoted himself to Gyujanggak activities for the next 37 years. He was known to be diligent in all his tasks, small or large, in addition to major painting duties including Gamdong (監董, a temporary official post to supervise and manage special projects such as civil engineering works or publication of books), royal portrait painter for Jeong Dynasty, and production of Hwaseongwonhaengdobyeong. With his talent and attitude, he was a trusted painter, being appointed several times as an official (burok, 付祿) during both Jung and Sun Dynasties.
 In addition to his official duties, Kim Deuk-shin was also active in his private works. He grew himself as a painter by interacting with important artists of the Joseon Dynasty, such as Kim Eung-hwan who came from a similar background, as well as Kim Hong-do and Lee In-moon. He received private orders through these personal relations, resulting in general paintings of various genres, as evidenced by his works such as Gosangugok-sihwabyeong and Hanjgangjooyouaheokdo cheob.

Experimental Investigation on Black Cotton Soil Mixed with Tyre Waste

Abstract: Expansive soil or black cotton soil are one of the problematic soil. Settlement of the structure, cracking in the different component of the structure etc. are some major problems caused in the structure constructed over such soil. The Stabilization is process done for improvement of existing soil by using an admixture. Rubber crumbs can be treated as admixture. The potential of using rubber from warm tyres in many civil engineering works has been studied for more than 30 years. Applications where tyres can be used have proven to be effective in protecting the environment and conserving natural resources. Hence in this study attempt is made study to behaviour of black cotton soil using rubber crumbs in terms of stability behaviour. Keywords: Black cotton soil, Rubber crumbs.

Influence of water content on the basic friction angle of porous limestones—experimental study using an automated tilting table

An accurate evaluation of the shear strength of discontinuities is frequently a key aspect for determining the safety of mining and civil engineering works and for solving instability issues at rock mass scale. This is usually done by using empirical shear strength criteria in which the basic friction angle (φb) is a relevant input parameter. Tilt testing is probably the most widespread method to obtain the φb due to its simplicity and low cost, but previous research has demonstrated that the results are strongly affected by several factors (e.g. surface finishing, cutting speed, specimen geometry, wear, time and rock type). In this connection, despite it is well known that water significantly reduces the mechanical properties of sedimentary rocks, very scarce research has focused on assessing the impact of the variations in water content on tilt test results. With the aim to fill this gap, saw-cut slabs of three limestone lithotypes were tilt tested in dry state, wet condition (fully water saturated, non-submerged samples) and under exposure to an environmental relative humidity (RH) of 90%. The results revealed that full water saturation caused moderate φb reductions in two lithotypes and a φb increase in one lithotype. This can be explained by their different microstructure and mineralogy, which makes that lubrication effect prevails over suction effect or vice versa. However, the exposure to a high RH environment did not cause significant φb variations. In addition, some important considerations related to tilt testing are provided and discussed, such as the intrinsic variability of the sliding angle (β) and the impact of multiple sliding on the same rock surfaces on β.

Purification of selenium-containing leachate in wastewater tanks at a tunnel construction site

The leachate containing heavy metals which generated from excavated soil and rock in the civil engineering works appropriate measures are required. We conducted indoor and outdoor experiments to purify heavy metal-containing leachate using a water tank, and proposed a method for treating heavy metals using the purification function of plants at civil engineering works. The plant used was Eleocharis acicularis, which belongs to the Cyperaceae family. The results of the indoor tank experiment on selenium indicated a decrease in the selenium concentration in the leachate from 0.093 to 0.008 mg/L in 14 days. The selenium content per kg of Eleocharis acicularis based on dry weight increased from 0.010 to 0.205 mg, indicating that the plant absorbed selenium. The outdoor tank experiment revealed that the selenium concentration in the leachate decreased from 0.090 to 0.007 mg/L in 21 weeks, and the daily absorption of selenium was 0.0005 mg/L. The lead concentration decreased from 0.004 to 0.001 mg/L in one week, and the arsenic concentration decreased from 0.003 to less than 0.001 mg/L in three weeks. Calculation of the leachate purification cost using Eleocharis acicularis under the current outdoor experiment conditions resulted in a 56% treatment cost reduction compared with the regular treatment cost.

Damage tolerance in engineering components: Implementation to anchor heads

Damage tolerance is commonly used as a design criterion in some engineering fields, such as aerospace engineering, but is not usual in civil engineering, where structural safety often relies on safety coefficients. This work presents a study on how using damage tolerance for designing post-tensioning anchor heads, usual mechanisms in many civil engineering works, can be useful for building safer structures. Damage is simulated using 2D and 3D finite element models, considering axisymmetric damage and single damage, respectively. The influence of several aspects, such as the crack depth, the crack orientation angle or the shape of the anchorage, is studied. Lastly, a specific anchorage geometry is analysed using the damage tolerance concept to show that this approach may help in the design of this type of elements.

Petrographic and Geotechnical Characterization of Granites from the N’Goura Massif (Center-Sud/Tchad): Implication for their Used in Civil Engineering

This work deals with the petrographic and geotechnical characterization of rocks from the N'goura massif with focus on their use in civil engineering. The study area is located in central southern Chad, about 205km to the north of N'Djamena. The N'goura massif is monzogranitic with two micas. The rocks outcrop as blocks, slabs and balls displaying fine, medium and coarse grained minerals. Monzogranite is composed of 34% quartz, 32% alkali feldspar, 26% plagioclase, 4% biotite, 2% muscovite and 1% chlorite on average. Geotechnical data show that the aggregates obtained from this rock have a Los Angeles coefficient ranging from 22.70 to 38.70% with an average of 30.70%, a Microdeval coefficient ranging from 4 to 13% with an average of 8.5% and a dynamic fragmentation coefficient ranging from 11.43 to 18.57% with an average of 15%. These results indicate that the studied materials are suitable to be used for construction and civil engineering works. The correlation between petrographic and geotechnical data reveals that the size (texture), grain structure and mineralogical composition (Qtz, Kfs and Bt+Ms+Chl+Ser) have an influence on the geotechnical behavior of these materials.

EVALUATION OF THE SUBSURFACE STRUCTURES IN PART OF FEDERAL UNIVERSITY OF GUSAU CAMPUS , ZAMFARA STATE, NIGERIA

Geo-electric evaluations of the subsurface structures of federal University Gusau Campus, Zamfara State, Nigeria were carried out using vertical electrical soundings technique (VES). The area lies within the Pre-Cambian Basement Complex of Northern Nigeria. Thirty-six (36) vertical electrical soundings (VES) along six profiles (A-F) were carried out during the survey. The surveys were carried out on grid 500m by 500m. The data obtained were interpreted using computer based program named Zohdy. The result of the interpreted curves reveals three distinct geo-electric curves types were delineated: K, H and HK-curves with H-type having the most prolific aquifer. The result also shows 3 geo-electric layers which were confirm by some borehole lithology. The aquifers in the study area are likely to be found in the fractured basement layers of western and southeastern parts of the study area. The civil engineering work can be sited mostly in the northern and southwestern parts of the study area which are the region of shallow basement within t=he study areas. Further boreholes in the area should reached an effective depth of 75m to 90m and the borehole be supervised by a certified hydrogeologist for optimum groundwater yields. Pumping test should be carried out in order to ascertain the size and type of submersible pump to install.

Physical and mechanical characterization of pyroclastic materials in Baleng area (Bafoussam, West-Cameroon): implication for use in civil engineering

Bafoussam, like other regions along the Cameroon Volcanic Line has huge pyroclastic resources. These materials are widely used in civil engineering works and result from different volcanic activities and therefore display locally different geotechnical properties. Thus, pyroclastic rocks in the Takouche quarry (Baleng-Bafoussam) were subjected to physical and mechanical analysis in order to determine their suitability and to optimize their use in civil engineering. Results indicate that the Takouche pyroclastic rocks are organized in five strata according to their color, structure and grain size. Except the stratum 2 with a water content of 14.4%, the others and the mixture of all strata displayed a low water content (> 7%) and therefore a low percentage of fine particles and are suitable for the production of concretes and realization of pavement bases. Based on absolute density (2.53–2.75 t/m3), pyroclastic materials of Takouche are common aggregates of the ungraded sand type and can be used for road construction and concrete works. The sand equivalent (69.0–92.8%) and the absorption coefficient (0.01–0.14%) reveal that these materials are very clean sands and contain poorly accessible pores. However, materials of stratum 2 with a sand equivalent of 69.0% and absorption coefficient of 0.14% allow the formation of concretes, exclusively with the use of Portland cement. The optimal dry density (1.83–2.07 t/m3) and optimal water content (8.0–12.5%) which are Optimum Proctor Modified parameters evidenced that materials from stratum 2 require treatment/correction before their use in road embankments. Meanwhile, materials from the remaining strata and the mixture of strata can be directly used and need to be improved only as base layer for heavy traffics T4 and T5. Referring to the 95% CBR values which range from 25 to 98, materials of stratum 1 and the mixed strata can be used as base layers for T3 traffic. In the mean-time, materials from stratum 3 and stratum 4 can be used as base layers for roads with a low volume of traffic. Nevertheless, materials from stratum 2 with a 95% CBR value of 25 need to be improved before their use as base layer. Moreover, the particle size distribution curves of materials extracted from stratum 1 to stratum 4, and the mixture of all strata do not belong to any particle size grading of sand for concrete. This study suggests proposals with the aim to improve the quality of the studied materials for their better use as concrete sand and backfill material. The correction involves the addition of fine volcanic ash to the pyroclastic rocks collected near the Takouche quarry. The resulting gains in compressive strength of concrete are quite considerable and vary from 52.87% to 97.23%, compared to the strength of concrete usually formulated by local users. The CBR coefficient after correction increases significantly with the maximum value of 115. Finally, the corrected aggregates provide good characteristics for their better use in road construction and concrete formulation.