Construction Quality Assurance Research Articles

Factors affecting the tensile strength of bituminous geomembrane seams

The tensile shear strength, break location, and constant tensile load failure times are examined for seams made from one 4 mm-thick bituminous geomembrane (BGM) product, with corresponding observations specific to that material. In short-term tests, failure is observed within the sheet material once the seam strength exceeded 0.8 times that of the sheet material. The effects of seam thickness reduction and overlap width on seam strength are examined for two methods of seaming. Seams with a short-term strength meeting or exceeding 80% of the sheet strength are subjected to constant tensile loads between 18 and 55% of sheet ultimate strength and the time to failure is reported. The relationship between short-term seam strength and time to failure under sustained load and thickness reduction and squeeze-out is investigated. Constant tensile load testing is proposed as a construction quality assurance procedure to assess the degree of geotextile engagement of field seams.

Implementation of Quality Assurance and Quality Control in Construction and Management for Project Effectiveness

Implementation of Quality Assurance and Quality Control in Construction and Management for Project Effectiveness

Preparing England's further education system for zero-carbon construction skills

Skills issues for craft trades in building decarbonisation often focus on improving technical knowledge, but known problems of quality assurance in construction also include ‘soft’ employability skills, and the application of sustainability values in practice. New course content is a necessary but not sufficient component of changing practice. The real demand for skills and actual use of skills in the workplace are just as important as new skills supply. A deliberative workshop with 40 expert stakeholders investigated the preparedness of the education and training system for zero-carbon construction skills. Several challenges emerge from this research. The market context for jobs and skills training shows how the over-narrow focus on new courses leads to waste and failures. Policy has an important role to play in developing minimum vocational standards through licensing, allied to consistent, long-term industrial strategy. The low prestige of further education and vocational training hinders real skills development and recruitment and retention of the workforce. Colleges operate with limited resources and competing priorities, creating real constraints on important activities like teacher training. Short courses and continuing professional development have no common standards or link with initial education and training, leading to piecemeal learning of unknown quality.

Release potential, neglected leakage and reduction countermeasures of COD and Ammonia in MSWLs

In order to eliminate the impact of the industrial revolution on the environment and improve the water ecological environment, pollutant discharge reduction is imperative. With the acceleration of global discharge reduction process, the huge pollutant release potential and potential environmental effects of municipal solid waste landfills gradually appear, but its release amount and intensity have not been quantitatively revealed. We propose a coupling method of parameter stochastic simulation and physical process model simulation to estimate the hidden leakage of large-scale regional municipal solid waste landfills, and provide a methodology for estimating the hidden leakage of landfills in other countries and even in the whole world by taking China, which has the largest amount of waste generation among developing countries, as an example. Prior to the implementation of stringent construction quality control and assurance management requirements, the average annual leachate generation potential over the entire life cycle of 2600 landfills in China was estimated to be 4.66 × 108 m3, in which the concentrations of COD and NH3-N are 5.38 × 102–6.48 × 104 mg/L and 6.10–3.50 × 103 mg/L, respectively, and the total amounts are 5.21 × 103–7.81 × 108 t and 8.09 × 102–6.65 × 107 t, respectively. About 14 % of these pollutants may leak into the environmental media through the landfill liner with the average number of holes of 21.5/ha. For different regions, the overall release, discharge and leakage of COD and NH3-N in East China account for 35.70 %, 36.68 % and 29.60 % respectively, making it the region with the highest potential for discharge and risk of leakage. Meanwhile, the implementation of mandatory regulations related to leachate generation and control has led to a significant reduction in the leakage of pollutants. For instance, comprehensively detecting and repair of holes in the impermeable liner has reduced the number of holes to 2/ha, resulting in a reduction of >90 % in the leakage of pollutants.

Digital Technologies for Quality Assurance in the Construction Industry: Current Trend and Future Research Directions towards Industry 4.0

Despite the growing rich and fragmented literature focusing on quality assurance (QA) and Industry 4.0, the implementation of associated individual digital technologies has not been fully evaluated and synthesised to achieve adequate QA in the construction industry; hence, it has received limited focus. This study, thus, aimed to organise, evaluate, and synthesise the current literature on individual digital technology applications in QA in the construction industry and propose future research directions. A literature review approach was adopted for this study along with Deming’s cycle framework to address four research questions: (1) What is the status of the state-of-the-art in the literature? (2) What digital technologies have been applied for QA in the construction industry? (3) Which areas in QA processes have experienced digital technology applications, and what are the applications? (4) What are the limitations of the existing studies and future research directions of digital technologies for QA in the construction industry? The findings showed an increasing trend of research on digital technology for QA in construction since 2017. This cuts across 23 countries with six different research methods published across 18 different publication sources. Four categories of digital technologies were revealed to have been adopted for QA in construction based on the functionality of the technologies: data collection technologies, decision-oriented technologies, collaborative technologies, and transparency and security-related technologies. Evaluation with Deming’s cycle framework revealed that digital technologies have a high level of application at the “do” phase, improving the quality management process during construction towards achieving pre-stated quality requirements. This includes mostly collaborative technologies, consisting of BIM technologies. Limitations of the existing studies were further identified, and this led to five research directions: interoperability of technology development, integrated digital technologies for QA of prefabricated and modular construction, integrated digital technologies for QA of cross-border construction logistics and supply chain, digital innovation for sustainable QA, and moving beyond the technical solution. The study showed a significant contribution to both academia and the industry in the built environment.

The system for determining the technical acceptability of construction products – the experience of Europe and Asia

Determining the technical acceptability of construction products becomes a determining factor that shapes trade, innovation and safety standards. The article reviews the system of determining the technical acceptability of the EU and some Asian countries. The European experience, embodied by the CE marking system, establishes a uniform approach in the EU member states. The importance of studying the European experience is emphasized by the orientation of Ukraine towards joining the EU, which will be facilitated by the transition of the construction sector to European standards. European countries have harmonized standards, such as the EN series, which begin with basic requirements for construction products. CE marking combined with conformity assessment procedures ensures compliance with strict quality and safety standards. Competent authorities have successfully addressed the role of third-party verification, while the Construction Products Regulation (CPR) has a level of regulatory oversight. This experience offers Ukraine a model of harmonization, promoting the creation of a single market and strengthening international confidence in its construction products. Asian countries, each with its own regulatory field, exemplify diverse approaches to determining technical acceptability. Countries such as Japan and China emphasize adherence to national standards and certification processes. The Japanese JIS standards and the JIS mark together with the Construction Quality Assurance (CQA) system are technical compliance standards not only in construction. Understanding the nuances of approaches in Asia gives Ukraine knowledge about adapting its own systems to regional requirements. The study of international approaches to the construction of a system for determining the technical acceptability of construction products and structures will contribute to international trade, ensuring the quality and safety of products, and innovations. Cross-border projects and the attraction of foreign investments contribute to the introduction of international practices that meet global standards. The introduction of the European system for determining the technical acceptability of building materials, which corresponds to the best international practices, not only the competitiveness of Ukrainian construction products, but also thanks to the global standardization of the construction industry, the economic integration of sustainable development, the experience of Europe and Asia allow to create a road map to ensure technical acceptability of construction products.

An automatic design-feedback process for structural prefabricated components quantity take-off calculation using BIM

ABSTRACT Prefabricated construction is spreading widely for its various advantages like construction efficiency, quality assurance, and environmental protection. However, ensuring project cost-effectiveness under the ever-increasing demands of prefabrication rate requirements has become a challenge. There is a growing need for Quantity Take-off (QTO) feedback on building components for stakeholders in the initial stages of structural design. This paper aims to create an automated design-feedback workflow for the structural QTO using the BIM-assisted visual programming tool Dynamo. The workflow includes model construction, data analysis, unit price data encoding, and design automation. The proposed method demonstrates the pattern of data exchange between stakeholders and is automated by the created visual programming scripts, breaking the original technical limitations, and presenting timely QTO feedback to the clients in a straightforward format. This study contributes to the field of design communication while satisfying the client’s requirements at the structural design stage.

Understanding the performance of bridge decks through full-scale accelerated testing

Understanding the long-term performance of bridges plays a major role in the selection of appropriate asset-management strategies, which eventually reduce life-cycle costs and extend the service life of a bridge. To understand bridge performance better, the Federal Highway Administration initiated a research project utilising accelerated testing of full-scale bridge superstructure systems subjected to cyclic moving wheel loads and freeze–thaw environmental conditions. As part of the research project, complementary non-destructive evaluation (NDE) techniques were used to assess the performance of a full-scale bridge deck during the curing and loading period. NDE results, shortly after construction, revealed a smaller cover depth of rebars in the middle section of the deck. This has likely created a preferential path for the subsequent deterioration of the deck. It was suggested to use a scaled version of the electrical resistivity (ER) values to improve the consistency between temporal ER measurements of the deck, and it was shown that combining construction information with NDE results can improve the interpretation of results. Overall, the results showed the importance of NDE for quality assurance of new construction and provided a better understating of the long-term bridge deck performance.

A BIM-based framework for road construction quality control and quality assurance

ABSTRACT Large-scale data processing for road construction monitoring may significantly improve the efficiency of quality control and quality assurance (QC&QA). However, the traditional construction data storage, management and analysis methods rely on paper documents and limited electronic files, leading to the low data utilisation, fuzzy data features and data value loss. This study proposes a BIM-based road QC&QA framework, which realises the real-time construction data integration in the information model, achieves data analysis and visualisation by the combination between the model and database, and uses structured construction data for QC&QA. Specifically, a BIM-oriented method for transmitting and storing road construction data in real-time, a BIM-oriented process for integrating road construction data, and a road QC&QA model based on AHP, ANN and GA throughout the entire road construction process are involved in the proposed framework. The proposed framework was tested through a case study using data from the Xintai Highway construction project. The results showed a significant improvement in data integration, visualisation and analysis during the QC&QA process. As a result, the overall construction quality of the Xintai project exceeded 95%, providing strong evidence of the effectiveness of the proposed framework.

Study of Regression Algorithms and Influent Factors between Intelligent Compaction Measurement Values and In-Situ Measurement Values

Intelligent compaction (IC) technology have been used for quality control and quality assurance (QC/QA) in subgrade construction. The effective regression correlations between Intelligent Compaction Measurement Values (ICMV) and In-situ Measurement Values (ISMV, including compaction degree and subgrade modulus ELWD) are the essential prerequisite of using IC technology for QC/QA. This paper presents the results from an experimental research study that was conducted from a practical subgrade project of China to explore the regression relationships between ICMV and ISMV. Three types of ICMV, including CMV, CCV and Evib, were collected along with the corresponding positions of the rollers. Two types of ISMV, containing compaction degree and ELWD, were measured by ring sampler method and light weight deflectometer (LWD) at specified test points, respectively. Based on these data, the influences of roller parameters and subgrade properties on the regression relationships of ICMV and ISMV were investigated. In addition, linear regression and 5 nonlinear regression algorithms were compared. The results suggest that ICMV reflect the stiffness of subgrade more than reflecting the density. In the regression of ICMV and ISMV, subgrade properties are more important than roller parameters while both of them should not be neglected. The influences of underlying stiffness and roller amplitude are linear while that of roller speed and moisture content are nonlinear. Nonlinear algorithms, especially the random forest, have the better performance compared to linear algorithm. Moreover, the combination of random forest and linear algorithm can further improve the accuracy of ISMV prediction.

Oxygen Diffusion Coefficients of Asphalt Mixtures and Their Impacts on Mixture Aging

The oxidative aging of asphalt binder affects the long-term performance of flexible pavement. Apart from the intrinsic property of asphalt binder, binder aging in an asphalt mixture is also affected by the mixture’s oxygen transport efficiency, which can be characterized by the oxygen diffusion coefficient. In this study, the diffusion coefficients ( Ds) of compacted asphalt mixtures of different designs were determined. The same mixture samples were also aged in one dimension for a relatively long period of time. Asphalt binders from different slices of the aged specimens were extracted and recovered, and their aging states were determined. Influences of Ds and air void content on binder aging gradient and binder aging extent in the mixture samples were systematically examined and compared. The results indicate that, as compared with air voids, Ds is more closely related to the aging susceptibility of asphalt binders in asphalt mixtures. It may serve as a useful and convenient parameter in mixture design optimization, modeling and prediction of in situ pavement aging, and quality control and quality assurance (QC/QA) in pavement construction.

STUDY ON THE IMPACT OF BUILDING PRODUCTION PROCESS IMPROVEMENT ON MANPOWER AND QUALITY ASSURANCE OF CONSTRUCTION MANAGEMENT WORK

Long working hours for construction management engineers are a problem in the Japanese construction industry. Therefore, measures to reduce engineers' working hours and production process improvements such as front-loading are being considered. However, rapid changes must avoid damaging the important functions of the conventional production system. In particular, any negative impact on quality assurance must be avoided. In this study, the relationship between construction management and quality assurance is summarized, and influence of production process improvement is verified on the man-hours of construction management work and quality assurance, and issues are clarified.

Concrete quality issues in multistory building construction in Ghana: Cases from Kumasi metropolis

This study investigated concrete quality issues at eleven multistory building construction sites in Kumasi metropolis amid several cases of multistory building collapses in Ghana. The objective was to understand key aspects of concrete quality problems at multistory building construction sites in Ghana to help recommend strategies for improving building safety standards. Apart from observing construction practices at the eleven construction sites, fresh concrete and constituent materials were sampled from four of the sites. The materials were used to produce concrete cube specimens, generally replicating the mixing ratios utilized at the sites. The site- and laboratory-produced concrete was tested for 28-day compressive strength. The site observations indicated that aggregate sourcing, stockpiling and batching practices promoted variability in concrete quality. Concrete production at the sites followed the recipe method (nominal mixing ratios), employing either low-capacity concrete mixers or hand-mixing. Consolidation, curing and quality control testing of concrete were not regular practices, and segregation and honeycombs were common. The sites determined adequacy of mixing water by visual evaluation of concrete workability. Had water content been properly determined and measured, the compressive strength of the site-produced concrete, which ranged from 10 MPa to 18 MPa, could have been 26–100% higher. The compressive strengths of the site-produced concrete were 26–60% less than the minimum 28-day characteristic compressive cube strength of 25 MPa required for structural use in buildings in Ghana. If an appropriate water content had been used at the sites, the compressive strengths could have still been less than the specified 25 MPa by 9%, on average. These findings suggested that low concrete quality was a real issue and could pose significant building failure risk or performance inadequacy. While the Ghana Building Code contains several specifications that potentially promote high building construction quality, their enforcement was non-existent or weak. A collaborative system of construction quality assurance and training encompassing local government agencies, professional associations and laboratories of higher educational and research institutions is recommended to help improve access to material testing resources and high-quality technical expertise, as well as to disincentivize willful violation of construction regulations.

The impact of silo storage on the fatigue and cracking resistance of asphalt mixes

During production, hot mix asphalt plants can store mixes in silos for a few hours before they get transported to the job site. Additional aging and possible blending between RAP and virgin binders take place inside the silo which affect mix properties. This study addresses the impact of silo storage on mix fatigue and cracking performance. The flexural beam test has been widely established as a representative fatigue test, however due to its complexity, it is difficult to implement as a quality control test. The semi-circular bending test (SCB) and the indirect tensile asphalt cracking test (IDEAL-CT) are simple and quick tests that are currently being used by some state agencies to assess the cracking resistance of asphalt mixes. The ability of SCB and IDEAL-CT to predict fatigue-related cracking as compared to flexural beam testing is also investigated in this study. Four plant-produced mixes were collected before and after silo storage, and tested using flexural beam, SCB, and IDEAL-CT. It was noted that the SCB and IDEAL-CT are highly influenced by the mix stiffness, and the cracking resistance was reduced considerably with silo storage. This finding has important implications when using either of these tests for construction quality control and assurance. It was concluded that the flexibility index (FI) from the SCB and the cracking tensile index (CTindex) from the IDEAL-CT did not provide a direct measure of the fatigue performance as compared to the flexural beam test.

Impact of warming temperature on asphalt pavement overlay performance and cost: case study in New Jersey

This study aimed to quantify the impact of warming temperatures on flexible pavement overlay performance with the effects of various in-place air voids. The performance models in Mechanistic-Empirical (ME) Pavement Design were locally calibrated and used to predict pavement distresses. The findings indicated transverse cracking due to low temperatures would become less problematic with milder winters, while more extreme high temperatures in summers contributed to faster pavement deterioration especially in the fatigue cracking. The analysis results showed that using the historic climate inputs in pavement design would overestimate the service lives for asphalt pavement overlays. As the in-place air void increases from 5% to 7% under the climate change scenario, the predicted pavement life decreases by 3–4 years. Further analysis showed that, with the effects of warming temperatures, agency costs could be reduced by controlling in-place air void through pay adjustment in quality assurance of the pavement construction.

Quantifying In Situ Tack Coat Performance Using the TackBond Tester for Quality Control

In light of the various quality assurance (QA) issues pertaining to tack coats that occur during construction, there is a need for a means of verifying interlayer bond quality in situ. Despite the immense use of tack coat as a constituent in paving, there are no construction specifications with provisions for the quantification of tack coat bond quality in laboratory or field settings. In this study, a construction QA process for tack coat bond performance was proposed. A novel field tack coat bond strength test device, TackBond, was developed and used for this purpose. The performance of engineered (new tack coat technologies that are tracking less) and conventional tack coats was also evaluated in the laboratory and the field using the developed TackBond test system. The TackBond device was improved in this study by adding features that render it more practical, portable, accurate, and better suited for a variety of pavement surface conditions. Engineered tack coat performance was compared with that of tack coats used conventionally on both milled and overlay surface types. The suitability of the TackBond Test device for capturing the true response of each tack coat was first evaluated by comparing results from TackBond laboratory tests with monotonic direct shear tests (DST) on laboratory-produced samples. Strong correlations between the two test types were achieved. Results of field and laboratory TackBond tests showed that the in situ QA control process developed in this study could be effectively used to improve the in situ tack coat bond performance.

Benefits of Quality Assurance and Control in Construction Industry

Quality assurance and control has been established by researchers to provide guidance for establishing an appropriate quality management procedure, in order to lower cost, increase productivity and customer's satisfaction, as well as market share in construction. This can assist construction industry to achieve successfully, their objectives, and ensure that all phases of construction projects consistently meet client's requirements. Basically, the objective of the study is to assess the level of quality assurance and control in construction through compliance evaluation and assessing the benefits and factors of implementing quality assurance and control on construction projects in Abuja and Environs. The research methodology adopted was an in-depth literature review and questionnaire administration while the data collected were subjected to descriptive statistical analysis through the application of percentage, frequency, mean and score. The findings have shown that construction firm’s adherence and compliance to International Standard Organisation series is low. The benefits of adopting Quality assurance and control are to improve site management, enhance reputation for good design and proper effective planning. It also highlighted factors affecting quality assurance and control implementation to be incompatible tendering procedure, design complexity, poor performance of quality and low tendency for team work. Finally, the measures for improving quality standard are enforcement of quality standard by agency of government and regulatory bodies and provision of training service on quality assurance. The study also recommends that all stakeholders need to understand the importance of quality assurance and control standards and also inculcate them throughout the design productive phase of their projects.

Research progress on the protection and utilization technology of water resources for coal mining in China

Water shortage is a global problem, and China is one of the most water-scarce countries in the world. The reverse distribution of coal resources and water resources has made the protection and utilization of water resources for coal mining in China a major technical problem for the green development of coal. Western China has become the main coal-producing area, but the ecological environment in the region is fragile, the evaporation of water resources is large, and the evaporation loss after mine water discharge is the main reason for the current annual loss of 6 billion tons of mine water in coal mining in China. The technical progress and engineering application characteristics of the protection and utilization of water resources in coal mining are systematically analyzed. After nearly 20 years of technical exploration and engineering practice, Shenhua Group broke through the traditional concept, put forward the technical concept of mine water storage in the goaf for the first time, overcome the technical problems such as water source prediction, reservoir site selection, reservoir capacity calculation, dam construction, safety control and water quality assurance, and built a technical system for underground coal mine reservoirs. This technology has been fully implemented in the Shendong mining area, and will be promoted and applied in other mining areas in the western region, opening up an effective technical way for the protection and utilization of coal mining water resources.

Quality Management Practices in Building Construction through Questionnaire Survey

Quality management systems are being operated in almost all sectors for products and services in the present time. In the construction sector quality control and quality assurance are of great concern for the construction project managers as the poor quality of construction results in early defects and failure of the structure this lowers the reputation of the company and leads to heavy repair costs. Further extra expenditure in achieving quality control and quality assurance is compensated by the advantages gained in the form of less maintenance, better quality and effective utilization of construction resources. There are many problems in applying the quality management effectively in construction due to its typical nature. There is a need to evaluate the effectiveness of quality management system (QMS) in construction projects. In the present work an effort is made to assess the quality management and quality assurance practices awareness and implementation among the construction personnel involved in building construction. A questionnaire containing questions related to quality control and quality assurance aspects of building construction is prepared and send to the construction personnel in Gwalior and nearby cities of Madhya Pradesh, India.

Experimental technique of defining the elastic modulus of bulk materials in laboratory conditions

Defining the elastic modulus of bulk materials is an important issue in quality assurance of design and construction of motorway bases. The analysis of current regulatory framework shows that there are no applicable methods for defining the elastic modulus of loose (bulk) materials in laboratory conditions. Moreover, if new or underinvestigated materials are used for motorway bases, it is necessary either to abandon their use or define their compliance with the regulations after motorway base construction. In view of the latter, an experimental technique and a device for defining the elastic modulus of bulk materials in laboratory conditions are developed. Following this technique, the elastic modulus of 5 mm – 20 mm, 20 mm – 40 mm crushed dump blast furnace and steelmaking slags was defined. Comparison of the obtained results with the recommended design values of the elastic modulus of similar materials shows good convergence (the difference is within 8%). There is no connection between the diameter of a stamp transmitting load to a sample and the specified value of the elastic modulus. Deviations do not exceed 10% for ∅50 mm, ∅120 mm, ∅150 mm stamps.