Internet of Things Based Real-Time Monitoring System for Early Age Properties of Concrete

Abstract

Automation in the construction industry is indispensable to significantly improve productivity, quality, economy, safety, flexibility, and accuracy. The possibilities of recently introduced Internet of Things (IoT) based systems are promising to attain a higher level of automation in the construction industry. Real-time monitoring of various parameters of concrete using IoT technology can leverage the process of automation in the construction industry. The research presented in this thesis poposes a novel, cost-effective,and easily deployable IoT-enabled automation system for the real-time monitoring of early-age concrete properties. Some of the most important properties include early age concrete compressive strength and plastic shrinkage. The estimation of the early-age compressive strength of concrete is crucial for quality control in the construction industry. The first part of the thesis proposes an innovative and cost-effective IoT-enabled system for the real time monitoring of early-age concrete strength using the well-established maturity method. The proposed system consists of temperature sensors and Wi-Fi micro-controllers which are connected to a cloud-based platform. Five selected concrete mixes are used to demonstrate the proposed system. The maturity relationships for the selected mixes are developed in the laboratory as per the relevant standards. The early-age compressive strengths of the selected concrete mixes predicted by the proposed system are found to match well with the actual compressive strengths obtained from the break test. The propo ed system is found to be effective in the automation of the maturity method that can trigger the implementation of user-friendly internet/mobile applications. Timely removal of formwork is one of the crucial aspects of construction management that directly influences the safety and quality of the structure as well as the economy of the project. Code recommendations in this regard are not widely practiced because of the difficulties in their implementations. Also, such code recommendations are not robust for all the possible construction conditions. The next part of this thesis demonstrates the application of an IoT-enabled system that notifies the minimum striking time of vertical formwork based on a specified target compressive strength.The implementation of the proposed system is demonstrated on three concrete columns. The proposed system is found to be suitable for any construction condition and can be easily implemented a tthe site.The hot and dry condition often induces plastic shrinkage cracks on concrete slabs and pavements. Such cracks are a concern for the concrete construction industry,as it affects the quality and long-term performance of the concrete structure. Existing approaches to monitoring plastic shrinkage at the site are time-consuming, labour-intensive, and expensive. As a result, these approaches are not attractive to the construction industry and are not generally practiced at the site. The next part of this thesis proposes a novel, costeffective, and easily deployable IoT-enabled system to monitor plastic shrinkage in realtime. Two alternative systems are proposed, one of which monitors the evaporation rate following the recommendation of the codes and standards. However, existing approac es have not considered the status of surface bleed water despite its essential role in monitorin plastic shrinkage. Therefore, the other alternative system is proposed based on the availability of the surface bleed water sheen. The effectiveness of the proposed system is validated by laboratory experiments on three sets of concrete specimens. The last part of the thesis attempts to incorpo ate Long Range (LoRa) technology into the IoT applications for the construction industry in order to take advantage of its large transmission range. This emerging technology is being used in many civil engineering applications such as water quality control, equipment tracking, etc., and the use of this technology is likely to multiply in the coming years. However, the energy efficiency and environmental impact assessment of such LoRa-based systems have not been addressed in the published literature so far. This thesis, therefore, explore the effect of transmission parameters on power consumption and proposes a scheme for controlling transmission parameters to improve the energy efficiency of LoRa end nodes. The effectiveness of the proposed scheme is demonstrated through a case study on a real-time monitoring system which is crucial for quality control and construction management.