Construction Technologies and Architecture Vol. 15

Abstract: At present, concrete blocks serve as the primary construction material in civil engineering due to their convenient material selection and impressive compressive strength. However, their limitations in terms of low tensile strength, poor toughness, and susceptibility to cracking hinder their progress. To enhance the flexibility and resilience of concrete, incorporating fibers is a viable method to develop a composite material. Concrete blocks, pavers, and kerbstones are widely using in construction applications. However, this is susceptible to cracking, especially under heavy loads or in harsh environmental conditions. Pine needles is a promising new material for reinforcing concrete. This is strong, durable, and sustainable. Pine needle is a promising material for reinforcing concrete blocks, pavers, and kerbstones. It has been shown to enhance a wide range of concrete valuables, containing tensile strength compressive strength, flexural strength, toughness indices, and energy absorption. This makes it a better choice than other reinforcement materials, such as millet husk ash, PET bottle, sheep wool, and coconut-fiber rope, which have only been shown to improve certain properties. Based on the literature review, wheat straw should be the first choice for reinforcing concrete due to its superior performance. Fibers, following certain treatment or recycling processes, [specified material] has been documented for its utilization in various forms as construction materials. Consequently, the objective of this literature review is to provide a comprehensive overview of the potential of waste fibers in the production of concrete blocks, pavers, and kerbstones. This entails a specific focus on scholarly articles published within the last decade in highly regarded journals.

Abstract: The problem of corrosion in reinforced concrete infrastructure can be addressed by using fibre-reinforced polymer (FRP) bars, since they are a feasible alternative due to their non-corrosive nature. Basalt fibre-reinforced polymer (BFRP) bars have recently gained attention as a possible substitute for both of these materials because they are less expensive than Carbon Fibre-Reinforced Polymer (CFRP) and have greater tensile strength than Glass Fibre-Reinforced Polymer (GFRP). While considerable research has been conducted on CFRP bars and GFRP bars, studies on BFRP are limited, hindering its incorporation into design guidelines. Therefore, in this study, bond behaviour of BFRP bars in concrete is experimentally evaluated. This study concludes that although BFRP bar shows more slip than steel bar, its bond strength is comparable to that of steel bar. It is also found that the bond strength and maximum slippage reduced with an increase in the bars' diameter and embedment length. Furthermore, the bond strength improves as the cover increases. Furthermore, bond strength equations as proposed by ACI 440.1 R15, CSA S806-02, and CSA S6-06 underestimated the experimental bond strength.

Abstract: Excessive exploitation of fresh water and river sand has prompted researchers to investigate seawater sea sand concrete (SWSSC) as a viable alternative to traditional concrete in the construction sector. The mechanical properties of SWSSC columns are comparable to traditional concrete columns, and these properties can be further enhanced through confinement. Strengthening or retrofitting of SWSSC columns with Fibre reinforced polymer (FRP) sheets in a single-skin fashion is an effective and easy way to achieve this enhancement. This review summarizes the available literature on the experimental investigation performed to date on single-skin confined SWSSC columns using different types of FRP sheets under compressive loading. Full wrapping, partial wrapping, and non-uniform wrapping are the three wrapping strategies under this confinement scheme. Employed wrapping strategy, FRP material type, number of layers of FRP, cross-sectional shape of the columns, and concrete strength are the key parameters that influence the ultimate strength and ultimate strain of the confined specimens. The failure modes and stress-strain curve characteristics for the three wrapping strategies are discussed. Finally, some directions for future research work in this area are also proposed.

Abstract: Road congestion is mostly common in developing countries where the traffic is heterogeneous and where there is no proper lane discipline. Typical and live traffic state can be identified with the help of IoT-based technologies such as traffic state feature in Google Maps. One can also identify congestion points using this live traffic state which varies through different times of the day and affect road capacity. In this research, the congestion points that were identified by Google Maps are examined by conducting a route-specific survey. The survey is conducted at different times on weekdays and weekends to assess the variably in number of congestion points. In this research, the relationship is established between congestion points and traffic volume at different times of the day and a Chi-square test is performed to check the significance of this relationship. The result shows that the congestion points are significantly related to traffic demand which is higher at one time and lower at another. The result also shows that the trip purpose and trip direction significantly affect the traffic demand at different times of the day.

Abstract: Orange Line Metro Train (OLMT) started working in October 2020 with a flat fare system. The fare system was changed just after a couple of years to a distance-based fare system. Based on the data obtained from the Punjab Mass-transit Authority (PMA), and interviews with the passengers, this paper investigates how the users and the management of OLMT were affected by the fare change. Analysis reveals that the most noticeable change was the sudden increase in the average number of users per day, from 1,15,000 to 1,70,000. With the increase in the number of average daily users, the average revenue also increased from Rs. 4.6 million to around Rs. 5.1 million per day. Secondly, users were also facing a lot of problems like they had to stand in the long lines to buy tokens, and due to some technical issues, token machines were also not working most of the time. This was increasing their overall travel time. New ways of selling tokens/tickets, increasing revenue collection, and better service management have been suggested.

Abstract: Traditional taxis have an important place in urban mobility because taxis provide flexible, comfortable and door-to-door service to passengers. However, for the continuity of traditional taxi services, profitability analyzes were needed despite the sharing economy. For this reason, the focus of this study is traditional taxis. This study aims to analyze the profitability of traditional taxi services in the urban arteries of Istanbul. For this purpose, a survey was conducted with 35 taxis and 70 taxi drivers. Then a model was then developed consisting of the independent variables number of trips (TRP), total trip distance (DST) and efficiency (EFF) that affect the profitability of taxi services. Additionally, contour plots were used to more accurately evaluate the effect of independent variables. As a result, it was concluded that the most important variable affecting the profitability of traditional taxi services is the efficiency (EFF) independent variable.

Abstract: China-Pakistan Economic Corridor (CPEC) is considered a game changer for the continent of Asia, Pakistan especially. China has invested around US$ 62 Billion in the fully operational corridor. Contractual conflicts are a significant source of delay in CPEC projects. Contractual conflicts are mostly because of poor financial and management control over it. In this paper, we have discussed the types of contractual conflicts that occur in projects that cause delays and the approaches that will help minimize the conflicts for the smooth occurrence of projects. For this purpose, a questionnaire was prepared and distributed to the major stakeholders of the projects. Secondly, the contractual conflicts are discussed based on the Pakistan literature review and compared with those of other countries. Two case studies were conducted to examine its causes: (1) political involvement and legal issues, (2) procurement and contract management, and (3) land acquisition problems

Abstract: Pavement failure occurs mostly due to poor selection of aggregate, which is highly dependent on aggregate petrography. The limited number of studies has been carried out in the past to relate the minerology of aggregate with the asphalt mix performance. This research aims to link the minerology of aggregate to the rutting of the asphalt pavement. In this study three different quarries of aggregates were collected for study i.e., Pathargarh, Surajgali and Murunj, Pakistan. Physical and mechanical properties of selected aggregate were determined before preparing the mix design. Aggregate properties were well within the limit specified by National Highway Authority (NHA). Then performance tests i.e., Hamburg wheel tracker test were performed on the asphalt mix to determine the rutting. The results showed that Pathargarh and Surajgali aggregate contains 96 and 95 percent carbonate making it basic. In contrast 84 percent quartz were found in Murunj aggregate. Rutting value of Pathargarh is better followed by Surajgali i.e., 3.43 mm and then Murunj 8.63mm. This study concludes that carbonate aggregate has rough texture making it better adhesion with bitumen, while quartz has poor adhesion with bitumen due to its smooth texture making it more susceptible to rutting.

Abstract: Rigid pavement, crucial for vehicular travel, necessitates continual enhancement to withstand varying loads and environmental conditions. This study delves into the integration of fibers, such as steel and pine needle fibers, to augment the mechanical properties of concrete pavements. Plastic shrinkage cracks, a prevalent issue during concrete curing, prompt the need for effective crack control methods. Incorporating fibers mitigates this challenge by bridging cracks and enhancing post-cracking resistance. Hybridization of fibers further amplifies concrete's performance, improving properties like tensile strength and durability. Studies underscore the effectiveness of natural fibers like coconut and pine needle fibers in enhancing concrete toughness and reducing crack width. Furthermore, treatments for natural fibers, such as coconut shell fibers, have shown significant improvements in mechanical properties. Pine needle fibers, characterized by their cost-effectiveness and environmental friendliness, emerge as a viable option for reinforcing concrete pavements. Overall, this research underscores the importance of fiber reinforcement in rigid pavements, offering solutions for crack control, enhanced durability, and prolonged service life.

Abstract: In the realm of civil engineering, scientists and engineers are striving to enhance the performance of Portland cement concrete (PCC) by incorporating organic waste materials, particularly wheat straw fibers. These fibers, alongside polymers, are key components in reinforcing cementitious concrete. They have been extensively studied and found to positively impact plain concrete, leading to the development of fiber-reinforced concrete (FRC). This study innovates construction through unique random fiber inclusion, diverse types, and addressing maintenance overlays of rigid pavements. This concept resembles a two-sided coin, with one side involving the random integration of fibers into the matrix, commonly seen in applications like Portland cement concrete pavement slabs and canal lining. Extensive research efforts were undertaken to gather insights into the significance of fiber composites in the field of construction. This literature review examines papers published by well-regarded publishers, encompassing the latest and essential research findings. Consequently, the primary aim of this study is to consolidate the outcomes and hurdles associated with fiber-reinforced composites for rigid pavement overlays, offering practical solutions to optimize concrete for enhanced pavement performance and sustainability. Our study's primary goal is to investigate the alterations in wheat straw fiber-reinforced concrete (WSFRC) materials through random fiber inclusion and explore the implications of different fiber types, mixing procedures, and construction challenges. A comprehensive literature review reveals three main objectives for incorporating fibers into concrete pavement overlays: enhancing mechanical properties, developing electrically conductive mixtures, and providing a sustainable solution for waste fiber management. This research paves the way for improving the performance and sustainability of concrete pavements in civil engineering.