A Study on the Mechanical Properties of Green Concrete

Green concrete is a type of concrete that uses waste materials as one of its ingredients. Hazardous wastes like fly ash and silica fume can be used to partially replace cement in concrete, which varies in physical and chemical properties. On the other hand, the increase in automobiles in urban and rural areas has led to an increase in the number of waste tires, which promotes environmental pollution due to disposal issues throughout the world. This study aims to use waste materials which can partially replace cement and conventional aggregates in the concrete mix. Fly Ash (FA), Silica Fume (SF), and Plaster of Paris (PP) replaced cement, whereas Reclaimed Rubber (RR) partially replaced coarse aggregates by weight. This work is focused on experimentation and simulation of M 40 grade mix using the above four materials. 306 cubes were cast by replacing cement with FA, SF, and PP in 3% increments up to 24%. Similarly, coarse aggregates were replaced with RR using the same proportion. Compression tests were carried out using a Universal Testing Machine. 12% silica fume replacement exhibited maximum strength during individual replacement of materials in concrete, which is selected as the optimum percentage replacement. FA and PP developed ultimate strength at 9% replacement of cement in the concrete mix, which is considered the optimum replacement percentage. A Genetic Algorithm (GA) model was developed using a C++ program to simulate various combinations of FA, SF, PP, and RR based on individual optimum replacement percentage. Hence, 1600 combinations were identified with the above four materials. Hence, GA was used as a tool to simulate the compressive strength of concrete to reduce time and cost. During simulation of combined replacement using GA, very high and very low compressive strength values were neglected, and 32 combinations were selected based on optimum compressive strength values. Finally, five combinations (C1-C5) were recognized, which resulted in higher compressive strength than individual optimum values after simulation. The GA-based numerical results were validated by casting 15 cubes for all the five combinations. 15 beam samples of size 100 150 1500 mm were cast with the above five combinations, cured and tested using a loading frame. A load-deflection curve was plotted, which showed that material replacement increased the flexural strength of the concrete mix. Doi: 10.28991/CEJ-2022-08-05-012 Full Text: PD

Performance of Mortar Incorporating Heat-Treated Drinking Water Treatment Sludge as a Silica-Sand Replacement

This paper examines the possibility of using water purification wastes in the production of mortar. Within the study context, XRD and XRF analyses were performed to obtain the chemical composition of sludge. Moreover, heat-treated sludge at a temperature of 900ºC was used in the preparation of mortar mixes as a partial sand replacement (5, 10, 15, and 20% by sand weight) with a w/c of 0.48. Fresh mortars were tested for workability, and mortar samples with 7, 28, and 90 days curing ages were tested for dry density, absorption, ultrasonic pulse velocity (UPV), and compressive and flexural strengths. Besides, some regression modeling was conducted for each of the measured parameters. In general, the results showed that the use of up to 10% incinerated sludge by sand weight leads to a slight decrease in the workability and density of the mixture and a 10% increase in its strength. Nevertheless, mortars with sludge content of over 10% showed a significant increase in water absorption and a decrease in strength and other properties. Doi: 10.28991/CEJ-2022-08-08-08 Full Text: PD

Post-cyclic Loading Relationship Effects to the Shear Stress and Cyclic Shear Strain of Peat Soil

Peats originate from plants and denote the various stages in the humification process. This condition renders the peat extremely soft and can be considered problematic soil. Thus, this study is conducted to examine and comprehend the particularities of peat engineering behaviour in respect to the relationship effects to the shear stress and cyclic shear strain of peat soil various characteristics to establish suitable correlation. This study carried out by using triaxial testing described by geotechnical test standards BS-1377: Part 8: 1990. Methods of Testing Soils for Civil Engineering Purposes: Shear Strength Tests (Effective Stress) that required for consolidated undrained and consist of five main stages: saturation, consolidation, static, dynamic, and post-cyclic loading using the GDS Enterprise Level Dynamic Triaxial Testing System (ELDYN). The parameters of shear strength were obtained in the peak deviator stress at a maximum of 20% of axial strain by using an undisturbed sample with an effective pressure imposed of 25, 50, and 100 kPa. In this study, all specimens are subjected to cyclic loading up to 100 cycles based on a one-way loading system with strain-controlled conditions. Based on the analysis conveyed, the post-cyclic shear stress decreased compared to its initial value of about 65.56 kPa (PNpt-100 kPa) in static and decreased to 14.9616 kPa in post-cyclic (PNpt-25 kPa-1 Hz). The principal stress ratio (σ'1/σ'3) shows the maximum values of this ratio that are located in the narrow zone of 1.61 to 1.12. Doi: 10.28991/CEJ-2022-08-12-08 Full Text: PD

Numerical Parametric Study of Fully Encased Composite Columns Subjected to Cyclic Loading

This paper investigates the cyclic behaviour of steel-concrete encased composite columns. By investigating the cover concrete and the steel-concrete coefficient of friction on the behaviour (strength, ductility, stiffness, and energy dissipation) of composite columns subjected to combined axial load and cyclically increasing lateral load to improve the strength and performance of the composite column. Eight of the columns were designed to study the cover concrete effect, and eleven other columns were designed to study the coefficient of friction effect in the dynamic behaviour to the cyclic load. Additionally, in this study, the finite element models created in ANSYS software were verified and calibrated against previously published experimental results (load-displacement curve, load capacity and failure mode). The numerical results obtained from the finite element model indicate that the ductility and the energy dissipated increased by +11.71 and +18.93% receptively by the increase of the cover concrete until reaching the limit of the cover concrete. Beyond this limit, the ductility and the energy decrease by 27.33 and 24.97% receptively. The results also indicate that the ductility and the energy dissipated increased by 12.62 and 7.82% receptively by the increased coefficient of friction until reach 0.6, after that the energy decreases by 4.47%. Doi: 10.28991/CEJ-2022-08-01-04 Full Text: PD

Effect of Liquefaction Induced Lateral Spreading on Seismic Performance of Pile Foundations

Seismically active areas are vulnerable to liquefaction, and the influence of liquefaction on pile foundations is very severe. Study of pile-supported buildings in liquefiable soils requires consideration of soil-pile interaction and evaluation of the interaction resulting from movement of soil surrounding the pile. This paper presents the results of three-dimensional finite difference analyses conducted to understand the effect of liquefiable soils on the seismic performance of piles and pile groups embedded in stratified soil deposits using the numerical tool FLAC3D. A comparative study has been conducted on the performance of pile foundations on level ground and sloping ground. The soil model consists of a non-liquefiable, slightly cemented sand layer at the top and bottom and a liquefiable Nevada sand layer in between. This stratified ground is subjected to 1940 El Centro, 2001 Bhuj (India) earthquake ground motions, and harmonic motion of 0.3g acceleration. Parametric studies have been carried out by changing the ground slope from 0° to 10° to understand the effects of sloping ground on pile group response. The results indicate that the maximum bending moments occur at boundaries between liquefiable and non-liquefiable layers, and that the bending moment increases with an increase in slope angle. The presence of a pile cap prevents horizontal ground displacements at ground level. Further, it is also observed that the displacements of pile groups under sloping ground are in excess of those on level ground due to lateral spreading. Doi: 10.28991/CEJ-SP2021-07-05 Full Text: PD

The Effect of Adding Steel Fibers and Graphite on Mechanical and Electrical Behaviors of Asphalt Concrete

Conductive asphalt concrete can satisfy different and multifunctional applications such as heating roads to get rid of snow and ice and assure auto-detection, auto-cure, and energy recovery. This research aims to evaluate the performance of asphalt concrete with additives like steel fibers and graphite powder. This work is based on destructive tests (direct tensile test FENIX) and non-destructive tests (electrical resistivity measures). The obtained results indicate that the tensile resistance, dissipated energy, and ductility module of asphalt concrete increased with the increasing steel fiber percentage. Direct tensile strength, cracking resistance, and dissipated energy increased as graphite percentage increased, while the ductility module decreased. Electrical resistivity decreased when it added steel fibers and graphite. Therefore, it found that tensile strength increased reversibly with electrical resistance. When adding steel fibers or graphite powder, the dissipated energy of asphalt concrete is increased while electrical resistivity is decreased. The dissipated energy of conductive asphalt concrete with steel fibers is higher than that with graphite powder. Electrical resistivity decreased significantly with increasing steel fibers, compared to electrical resistivity with graphite. The obtained results indicate that asphalt concrete cracking resistance is higher with the optimal percentage of steel fibers added at 1% and better mechanical performance. Doi: 10.28991/CEJ-2022-08-02-012 Full Text: PD

Construction Labour Measurement in Reinforced Concrete Floating Caissons in Maritime Ports

This research work attempts to approach the measuring of the working equipment necessary to make floating caissons for maritime work and their performances. With this objective, an empirical study has been carried out based on the construction of five floating caissons with a rectangular layout of 34.00 meters in length, 17.00 meters in width, and 19.00 meters in depth, lightened with 32 vertical cells. This work was carried out in the port of Granadilla, Tenerife (Spain). The updated scientific literature related to the execution of this type of floating structure refers to the importance of the calculation hypotheses, the actions to be taken into account, the service states or the importance of the choice of materials (concrete and steel). However, scientific research does not seem to face the problem of how to size the working team necessary to execute this type of structure. The work force is approached from the point of view of the adequate sizing of working groups. The important contribution of the article to the project and construction management literature is the development and capability of an easy-to-use optimization model for planning the labour and labour days required in floating caisson construction. The optimization model proposed in this research allows the project managers of a construction company to estimate the labour costs and teams necessary in the execution of the construction. This gives it a competitive advantage both in the construction phase and in the bidding phase for the award of the work. Doi: 10.28991/CEJ-2022-08-02-01 Full Text: PD

Integrated Framework for Inclusive Town Planning Using Fuzzy Analytic Hierarchy Method for a Semi Urban Town

Planning is a continuous process and must incorporate a regular evaluation of implementation and further revision for effective and efficient utility for the betterment of society through modification of the planning standards. Development plans for cities / towns are criticized for being rigid and static, having little regard for investment planning efforts, and taking a very long time in the process of formulation and approval. In depth analysis and review of the existing situation, covering the demographic, economic, financial, infrastructure, physical, environmental, and institutional aspects, is important so as to identify the strengths and weaknesses in the city overall development. In the present study, an attempt has been made to thoroughly review the existing planning standards adopted for the preparation and implementation of development plans in India, especially in Maharashtra. Since the development plan's objectives are not measurable, this study will use the Fuzzy Analytic Hierarchy Process (AHP) to assess their level of performance. For the purpose of identifying the various viewpoints of various stakeholders, field surveys and questionnaire surveys were conducted. This application can be used as an objective evaluation tool for planners and policy makers to improve planning practices and provide necessary knowledge for revising plans. The results indicated the importance of criteria from the pre-planning, preparation, and implementation stages of DP. These results were used for two semi-urban towns in Maharashtra regions and could also be used by planning engineers for further development of planning standards. Doi: 10.28991/CEJ-2022-08-12-07 Full Text: PD

Seismic Analysis of Double Unit Tunnel Form Building Subjected to Out-of-Plane Lateral Cyclic Loading

Most of the high-rise buildings for commercial and residential purposes in Malaysia are constructed using a tunnel formwork system. This type of building becomes a favor due to the fast construction and cost-effectiveness. However, the research on the behavior of Tunnel Form Building (TFB) under the seismic effect is still insufficient and requires further investigation. Therefore, the safety level of double unit TFB subjected to weak plane (out-of-plane) was investigated in this study. The TFB was designed using a non-seismic provision to represent an existing condominium building constructed in Selangor. Ten past earthquake records categorized as major, moderate, and low magnitudes were utilized. The behavior of the double unit TFB was analyzed using the Ruaumoko 2D program. The ultimate lateral load, displacement, pseudo-spectral acceleration (PSA), pseudo-spectral displacement (PSD), and mode shape of TFB were also analyzed. Based on the findings, most of the selected earthquake records exceeded the lateral capacity of TFB. The building experienced a major damage under 6.9 Richter scale of Imperial Valley, 7.3 Richter scale of San Joaquin Valley, and 7.9 Richter scale of Denali Earthquakes excitations. Therefore, these findings suggested if any similar magnitudes of unpredicted seismic events would occur in the future, significant damages may be experienced by the existing TFB in Malaysia. Doi: 10.28991/CEJ-2022-08-11-012 Full Text: PD

Numerical Analysis of Seepage Failure Modes of Sandy Soils within a Cylindrical Cofferdam

Soil seepage failure within cofferdams is a dangerous phenomenon that always poses difficulties for designers and builders of excavations in zones with high water levels. When the hydraulic head difference H between the upstream and downstream sides reaches a critical height, the downstream soil seepage failure occurs. Depending on soil properties, soil-wall interface characteristics, and cofferdam design, different seepage failure modes can be observed: heaving, boiling, liquefaction, or failure by reduction of the passive earth pressure. In the literature, there are differences, sometimes very large, in the critical value of the hydraulic head loss Hc/D inducing seepage failure given by several methods proposed for stability verification. Then, complex cases are generally approached using simplifying assumptions and adopting large safety factors to take account of uncertainties. In practice, geotechnical engineers deal with many kinds of excavations and different shapes of cofferdams, such as rectangular, square, or circular, which generate three-dimensional (3D) flow conditions. Axisymmetric seepage flow through the soil in a circular cofferdam is often used to model such 3D seepage flow. In this paper, using the numerical code FLAC, several numerical simulations are carried out in axisymmetric groundwater flow conditions to analyze the seepage failure modes of cohesionless sandy soils within a cylindrical cofferdam. The effects of the cofferdam radius, internal soil friction, soil dilatancy, and interface friction on the Hc/D value and failure mode are studied. The numerically obtained seepage failure modes are presented and discussed in various scenarios. The present results, illustrated in both tables and graphs, show a significant decrease in the value of Hc/Dinducing seepage failure, with a decrease in the cofferdam radius. They also indicate the sensitivity of the seepage failure mode to internal soil friction, soil dilatancy, interface friction, and cofferdam radius. As well, new terms are proposed for the seepage failure mode designations based on the 3D view of the downstream soil deformation. Doi: 10.28991/CEJ-2022-08-07-06 Full Text: PD