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The stone dust column was used to strengthen the sample and had a significant effect on improving the shear strength of the kaolin clay. The application of stone columns, which can improve the overall carrying capacity of soft clay as well as lessen the settlement of buildings built on it, is among the most widespread ground improvement techniques throughout the globe. The performance of foundation beds is enhanced by their stiffness values and higher strength, which could withstand more of the load applied. Stone dust is a wonderful source containing micronutrients for soil, particularly those derived from basalt, volcanic rock, granite and other related rocks. The aim of this paper is to evaluate the properties of soft clay reinforced with encapsulated stone dust columns to remediate problematic soil and obtain a more affordable and environmentally friendly way than using other materials.

In this study, the treated kaolin sample's shear strength was measured using the unconfined compression test (UCT). 28 batches of soil samples total, 12 batches of single stone dust columns measuring 10 mm in diameter and 12 batches of single stone dust columns measuring 16 mm in diameter. Four batches of control samples are also included. At heights of 60 mm, 80 mm and 100 mm, respectively, various stone dust column diameters were assessed. The real soil sample has a diameter of 50 mm and a height of 100 mm.

Test results show when kaolin is implanted with a single encased stone dust column that has an area replacement ratio of 10.24% and penetration ratios of 0.6, 0.8 and 1.0, the shear strength increase is 51.75%, 74.5% and 49.20%. The equivalent shear strength increases are 48.50%, 68.50% and 43.50% for soft soil treated with a 12.00% area replacement ratio and 0.6, 0.8 and 1.0 penetration ratios.

This study shows a comparison of how sample types affect shear strength. Also, this article provides argumentation behind the variation of soil strength obtained from different test types and gives recommendations for appropriate test methods for soft soil.

Construction delay is the most common issue and creates many adverse effects in any construction industry. This study has investigated the views of engineers, project managers and contractors on the causes of delay during a construction phase to identify potential delay factors, negative effects on project delivery and prioritize the delay factors.

An extensive literature review and interview with construction stakeholders have been conducted to identify potential causes of construction delays and design a questionnaire survey. The final questionnaire was designed with 40 potential delay factors, and a total of 102 valid Bangladeshi construction stakeholders responded to it. The result was analyzed by the relative importance index.

Among the 40 delay factors, the top five most influencing delay factors are “delay in progress payments,” “rework due to mistakes during construction,” “lack of skilled labor,” “poor monitoring and control of activities” and “delays in the making of a decision.” The top five most damaging effects of delay are “time overrun,” “cost overrun,” “disputes,” “arbitration” and “litigation,” among ten negative effects of construction delay. All construction stakeholders believe that the owner-related, consultant-related and contractor-related groups are the first, second and third most important groups of delay factors.

The outcome of this study would enable the Bangladeshi construction industry to develop strategies to overcome delay factors and their harmful effects. By focusing on the outcome of this research and prioritizing the critical factors, the construction industry of Bangladesh will be able to minimize construction delay significantly and propagate the progress of the construction industry by delivering quality projects timely.

Construction delay always causes massive damage to the advancing construction industries, which is no different in the case of Bangladeshi construction industries. This paper aims to investigate the major delay factors causing construction delays in public-funded, mixed and private-funded construction projects of Bangladesh. Also, it offers preventive suggestions from expert stakeholders to reduce the recurrence of delays.

At first, an extensive literature review was conducted to identify the thirty-seven major delay factors categorized under seven groups. A questionnaire was then developed for survey at ongoing construction projects at a different division of Bangladesh. Next, data from 110 respondents were collected, and the delay factors were ranked based on the Relative Importance Index (RII); lastly, probable solutions were suggested for top-ranked delay factors based on opinions from expert stakeholders in the construction sector of Bangladesh.

The overall RII ranking of the 37 delay factors showed “Construction mistakes and defective work,” “Contract modifications by the client” and “Adverse weather condition” as the top three factors causing the delay. For public-funded projects, “Construction mistakes and defective work” and “Slow decision making by a consultant” are the top delay factors. For mixed projects, “Slow decision making of the client” and “Construction mistakes and defective work ranked top, and for private-funded projects, “Financial problems and payment delay of the client” and “Adverse weather condition” ranked top. These nuances of ranking in individual project types ascertain that the causes of delay vary in terms of project features.

The outcome of this project will help identify the significant delay factors based on their severity of effectiveness associated with public-funded, mixed and private-funded projects in Bangladesh. The suggestions regarding preventing these delay factors obtained through the opinions of expert stakeholders can help reduce the effect of these delays in the context of Bangladesh and in countries where the similarity in construction environment prevails.

Previously, studies on construction delays in Bangladesh focused mainly on identifying the delays using qualitative analysis techniques. This study is based on a unique methodology of integrating quantitative research on delay factor identification and qualitative research on preventive measures following the opinions gathered from expert stakeholders in the construction sector.

Quality is a sensitive and high-priority issue in the global construction including in Bangladesh. This research is intended to provide necessary information to stakeholders and authorities for better management of the construction quality in Bangladesh. Therefore, this study seeks to find and prioritize the factors affecting the construction quality in Bangladesh.

In total 65 factors were extracted and categorized from the literature and expert panel discussion. Subsequently, these factors were designed in a questionnaire under 13 major groups for a survey where 176 construction professionals participated and returned their completed survey form. Collected data were tested by the Cronbach Alpha to check the reliability before proceeding to the Relative Importance Index (RII) analysis for determining the relative ranks of identified factors.

Statistical analysis of survey data represents that the most significant factors are: lack of management commitment, lack of technical skill and experience of the consultant, delays in progress investigation, political interference and contractor's desire for unrealistic profit. The most crucial major groups of factors influencing the construction quality are management, material, consultant, cost and time and contract-related major groups.

It will contribute to the body of knowledge, as it points out the impact of factors affecting quality in Bangladeshi construction. Authorities and stakeholders can be helped by the overview of the high and low ranks factors, understanding the diverse characteristics of factors and making more aware the industry about the quality issues which need to be a top concern to solve. Other developing countries that share the same socio-economic context as Bangladesh can be benefit from the results of this study to control quality issues in construction.

The current study mainly focuses on the effect of varying diameter recycled steel fibers (RSF) on mechanical properties of concrete prepared with 25 and 50% of recycled coarse aggregate (RCA) as well as 100% natural aggregate (NA). Two types of RSF with 0.84 mm and 1.24 mm diameter having 30 mm length were incorporated into normal and recycled aggregate concrete (RAC).

The fresh behavior, compressive, splitting tensile, flexural strengths and modulus of elasticity of all the mixes were investigated to evaluate the mechanical properties of RACs. In addition, specimen crack and testing co-relation were analyzed to evaluate fiber response in the RAC.

According to the experimental results, it was observed that mechanical properties decreased with the increment replacement of NA by RCA. However, the RSF greatly improves the mechanical properties of both normal concrete and RACs. Moreover, mixes containing 1.24 mm diameter RSF had a more significant positive impact on mechanical properties than mixes containing 0.84 mm diameter RSF. The 0.84 mm and 1.24 mm RSF addition improved the mixes' compressive, splitting tensile and flexural strength by 10%–19%, 19%–30% and 3%–11%, respectively when compared to the null fiber mix. Therefore, based on the mechanical properties, the 1.24 mm diameter of RSF with 25% replacement of RCA was obtained as an optimum solution in terms of performance improvement, environmental benefit and economic cost.

The practice of RCA in construction is a long-term strategy for reducing natural resource extraction and the negative ecological impact of waste concrete.

This is the first study on the effects of varying size (0.84 mm and 1.24 mm diameter) RSF on the mechanical properties of RAC. Additionally, varying sizes of RSF and silica fume added a new dimension to the RAC.