Concrete Delivery Research Articles

Personnel scheduling problem for ready-mixed concrete delivery

Personnel scheduling problem for ready-mixed concrete delivery

A GRASP algorithm for the concrete delivery problem

This paper addresses a novel variant of the Concrete Delivery Problem (CDP), which involves the efficient scheduling of ready-mixed concrete deliveries to construction sites while balancing the conflicting goals of minimizing transportation costs and maximizing customer satisfaction. In this study, we propose an exact formulation and a heuristic approach based on the Greedy Randomized Adaptive Search Procedure (GRASP) to tackle this challenging CDP variant. This variant introduces realistic side constraints, including driver working shifts, a minimum driver working time, and overtime penalties. Additionally, it considers the case where customers may request multiple types of concrete delivered within the same time window. We assess the performance of our heuristic using new instances generated for this problem and provide a comparative analysis with another CDP variant from the literature to demonstrate its effectiveness.

Analysis of the Effect of Layer Height on the Interlayer Bond in Self-Compacting Concrete Mix in Slab Elements.

This paper presents a study on the influence of the layered casting technology of self-compacting concrete (SCC) on the load-bearing capacity of interlayer bond in slab elements. The research was conducted on slab elements with dimensions of 750 × 750 × 150 mm, concreted from a single point of concrete delivery. The aim of this study was to analyse the influence of the height of the concreting top layer on the bond strength between the layers. The study utilised top layer heights of 50, 75, and 100 mm, which, according to the authors' experience, are the most common cases when making slab elements. The interlayer bond was determined by investigating the splitting tensile strength of cubic specimens cut from the concrete slabs. Computed tomography (CT) was employed to image the contact zone between the concrete layers. Based on the analysis of the CT imaging and the results of the strength tests, it was shown that the interlayer bond is influenced by both the height of the top layer and its free-spread distance from the casting point. A reduction in the interlayer bond strength was observed with decreasing the height of the top layer and increasing distance from the mixture supply point. The relationships obtained were linear and had a clearly negative slope. It was concluded that the valid recommendations and standards for the multilayer casting of SCC are too general. Therefore, we propose to detail the recommendations to reduce the risk of cold joints, which diminish the bond strength of the interlayer joints.

Digitalization of the Concreting Process in Construction

The delivery of concrete is a crucial process in construction projects, and any delay or error can cause significant setbacks and added costs. Thus, effective real-time management of concrete delivery is essential to ensure timely and successful project completion. In this paper, we will discuss a practical and manufacturer-agnostic approach to real-time management of concrete delivery for construction named BET 4.0 that is being conceived with a close partnership with a construction company. This application provides the possibility to optimize the whole concreting process as it establishes the connection between all the relevant components and stakeholders involved in the construction process, namely the concrete plant, the transport, and the construction site, interfacing with all actors involved, and benefiting from real-time data produced by installed sensors in the several components such as machines, plants, or construction elements.

Active BIM system for optimized multi-project ready-mix-concrete delivery

PurposeReady-mix concrete delivery problem (RMCDP), a specific version of the vehicle routing problem (VRP), is a relevant supply-chain engineering task for construction management with various formulations and solving methods. This problem can range from a simple scenario involving one source, one material and one destination to a more challenging and complex case involving multiple sources, multiple materials and multiple destinations. This paper presents an Internet of Things (IoT)-supported active building information modeling (BIM) system for optimized multi-project ready-mix concrete (RMC) delivery.Design/methodology/approachThe presented system is BIM-based, IoT supported, dynamic and automatic input/output exchange to provide an optimal delivery program for multi-project ready-mix-concrete problem. The input parameters are extracted as real-time map-supported IoT data and transferred to the system via an application programming interface (API) into a mixed-integer linear programming (MILP) optimization model developed to perform the optimization. The obtained optimization results are further integrated into BIM by conventional project management tools. To demonstrate the features of the suggested system, an RMCDP example was applied to solve that included four building sites, seven eligible concrete plants and three necessary RMC mixtures.FindingsThe system provides the optimum delivery schedule for multiple RMCs to multiple construction sites, as well as the optimum RMC quantities to be delivered, the quantities from each concrete plant that must be supplied, the best delivery routes, the optimum execution times for each construction site, and the total minimal costs, while also assuring the dynamic transfer of the optimized results back into the portfolio of multiple BIM projects. The system can generate as many solutions as needed by updating the real-time input parameters in terms of change of the routes, unit prices and availability of concrete plants.Originality/valueThe suggested system allows dynamic adjustments during the optimization process, andis adaptable to changes in input data also considering the real-time input data. The system is based on spreadsheets, which are widely used and common tool that most stakeholders already utilize daily, while also providing the possibility to apply a more specialized tool. Based on this, the RMCDP can be solved using both conventional and advanced optimization software, enabling the system to handle even large-scale tasks as necessary.

Replacing cement through data analytics and process control

Highway safety is a critical factor to one of the most vital parts of society's infrastructure. Slipform paving provides an economical means to quickly construct concrete barriers and drainage channels, which contribute to a highway's safety. This study follows a slipform paving company's journey in implementing an in-transit management system which can measure and adjust slump during the delivery of concrete. By allowing the system to manage the rheology, both productivity and material savings (through cement) were achieved. Furthermore, the system enables an immediately viable method to significantly reduce embodied carbon dioxide for the concrete industry.

Implikasi PTM terbatas terhadap Perkembangan Ranah Afektif dan Ranah Psikomotorik Peserta Didik pada Mata Pelajaran PAI di UPT SMA Negeri 1 Palopo

Focusing on the form of implementing PTM is limited to PAI subjects. The purpose of this study, the implications of PTM are limited to the affective and psychomotor domains of students in PAI subjects at UPT SMA Negeri 1 Palopo. This type of descriptive qualitative research.
 The results of the study show that the implementation of limited PTM is highly appreciated by teachers and students because the learning interactions are different when online so that students experience the direct transfer of knowledge, attitudes, and different learning experiences. Implementation of limited face-to-face learning is carried out in accordance with health protocol procedures, guidelines for implementing limited PTM during the New Normal period. The school has planned and carried out in accordance with limited face-to-face learning procedures, but in terms of implementing the teaching and learning process in class, the delivery of material is quite condensed, and only conveys important points and emphasizes the completion of assignments, so that students are driven by time and maximize time. available so that they must focus on following the lesson. Teachers do not use interactive learning models and do not involve innovative learning media that support the concrete delivery of information to students, so that this has implications for the development of the affective and psychomotor domains of students as well as student activities in schools and the development of these two aspects cannot be carried out maximally.

Benchmarking site-plant resource matching performance of ready-mixed concrete delivery and placing

Since on-time concrete delivery is important to both contractors and suppliers, performance benchmarking of the concrete delivery process, as actually achieved in practice, is a worthwhile undertaking of potential benefit to the construction industry. However, there has been no thorough such benchmarking in Hong Kong for 20 years, since the study by Anson et al. (2002). This research study has provided an up-to-date benchmark of the site/supplier resource matching, or coordination, performance for big building superstructure pours, based on study of the records of 77 pours placed on five buildings under construction in Hong Kong. This research study also aimed to assess whether there was any evidence to suggest that site/ plant coordination performance has improved since 2000, not least due to the adoption of advanced technologies, which nowadays monitor the locations of truckmixers in real time throughout the day. Of great importance to the industry, however, and the most significant finding arising from this study, is that there is no support for the proposition that site/supplier resource coordination has improved over that 20-year interval. Truckmixer position tracking systems need to be capitalised upon with the introduction of data analysis simulation software and optimising scheduling applied in real time.

Concrete placing crew and truckmixer productivities as affected by delivery scheduling policies

When ready mixed concrete is placed in forms on site, the goal is to ensure that both the placing crew is never idle when waiting for a delivery of concrete and that concrete delivery truckmixers never have to wait in a queue to be unloaded. This situation is almost never achieved in practice for a routine pour. Usually, both crews and truckmixers have to wait for some of the time. To better understand the behavioural characteristics of the concreting system, in terms of crew idle time and truckmixer excess time on site, simulation experiments were carried out to compare the effects of two truckmixer plant dispatch policies. For larger pours in particular, a serial dispatch policy is found more wasteful of truckmixer time than circulating dispatch as long as the correct size of circulating fleet is chosen. In addition, for serial dispatch, due to the system flow parameter variabilities seen in real life, it is suggested that to choose the theoretically optimum dispatch interval at the plant is wasteful of truckmixer time and that better coordinated plant and site resource matching requires slightly greater choice over the length of intervals.

Introducing a New Quantitative Evaluation Method for Segregation of Normal Concrete

The aim of this research is to provide a quantitative method for evaluating concrete segregation. Because of various conditions of concrete materials, mix proportions, and delivery, concrete can be segregated. The acquisition inspection executed in construction field for supplied ready-mixed concrete is an important quality control process for concrete. Among the inspections conducted at the project site, segregation of concrete mixture should be evaluated before placing the concrete mixture, currently a qualitative inspection on concrete segregation was conducted. For a normal concrete mixture with slumping behavior, shear slump or collapse slump often occur as an indication of segregation. The suggested evaluation index of segregation for normal concrete (EISN) was induced from the shape of the concrete slumping: relation between the maximum distance of flow and the minimum distance of flow. To evaluate the feasibility of EISN, two different concrete mixture conditions were tested. The recommended EISN parameter of segregation is 1.09 using the three grades of concrete quality. This new quantitative method of evaluating segregation of the concrete mixture is expected to contribute to a more efficient quality control in concrete construction.

Alternative methods of delivering concrete and mortar mixes to low-rise construction projects

Concrete mixes are usually delivered to construction projects with the help of special vehicles. Depending on its fluidity, cement setting rate, temperature and relative humidity of carriage conditions, as well as a distance and road condition, transportation of a concrete mix may be done in concrete mixer trucks and ready-mix delivery trucks, also in buckets and hoppers mounted on vehicles (bucket trucks). At the same time, it is necessary to reduce the number of transship operations as much as possible and, wherever practicable, unload a mix directly into the structure to be concreted. Each method of transportation has its rational areas of application. For low-rise construction characterized by small volumes, scattered construction sites, insufficient coverage by a good-quality road system, and a long distance from concrete factories, it is expedient to use alternative, non-dedicated to concrete mix transportation, types of vehicles equipped with their own lifting devices. The issues of application of drop-side lorries with crane manipulators and gantry hopper trucks for transportation of ready-mix buckets are discussed. The technical characteristics of general purpose vehicles and lifting equipment are described. Recommendations concerning fitting of various types of vehicles with portable hoppers are given.

From Mobility Partnerships to Migration Compacts: security implications of EU-Jordan relations and the informalization of migration governance

ABSTRACT Recent events in the Middle East and North Africa entailed a proliferation of policy tools for EU external migration governance. After the signature of Mobility Partnerships, the EU launched Migration Compacts, whose inner logic is to ‘avoid the risk that concrete delivery is held up by technical negotiations for a fully-fledged formal agreement’. This paper examines the development of the EU’s external migration governance and frames it into a formalization/informalization dichotomy. We argue that the EU-led securitisation of migration has contributed to the increasing informalization of EU-third countries agreements. The case of Jordan is relevant in understanding the EU’s approach, as a strategy to muddle through in a region in turmoil.

Estimating on-site emissions during ready mixed concrete (RMC) delivery: A methodology

Sustainability represents a critical challenge in the construction industry and many approaches have been developed to reduce the environmental impact of on-site construction processes. However, scant academic attention has been given to the environmental impact of logistical support for ready mixed concrete (RMC) on-site delivery emissions in developing countries. This paper develops a methodology for capturing emissions from RMC equipment and material during on-site delivery operations. A literature review was conducted to define and delineate upon greenhouse gases emitted during RMC operations and the appropriate methods to calculate them. A methodology was then developed and validated by analysing ten delivery cycle times in a case study. Data collected was analysed using simple descriptive summary statistics (viz: mean, bar charts and standard deviation). The study’s results illustrate that on-site emissions incurred were: CO2 account for 99.38 % of the total emissions from RMC equipment while HC (0.03 %), CO (0.11 %), NOx (0.26 %), PM10 (0.02 %), and SO2 (0.20 %) account for 0.62 %. Embodied CO2 in RMC also contributes majorly to emissions in on-site delivery operations. Alternative materials such as fly ash represent a viable means of reducing embodied emissions in RMC but proper handling is required to avert harmful environmental impacts. The study provides deeper insights into the on-site emissions arising from RMC delivery operations and a bespoke methodology that could be used as an organisational learning tool for RMC companies.

Recycled Concrete Based on Retour de Toupie Aggregates (Fresh Concrete Waste)

The toupie is a ready concrete delivery truck (BPE). Accidentally or negligently, if the concrete is not delivered on time, he makes and hardens. It enters the range of waste. In this study, fresh concrete is crushed and reused as a substitute for natural aggregates. A 2-variable experience plan (% sand and% gravel) was used to reduce the number of measurements. The replacement proportions used are 0%, 50% and 100%. Several mechanical and physical properties were measured including compressive strength, tensile strength and absorption. These results show a good correlation between the percentage of replacement and the properties of this concrete. Replacing 50% of natural aggregates (sand and gravel) with recycled aggregates results in a reduction of about 24% in the compressive strength of the concrete under test.

Using functional resonance analysis method to understand construction activities for concrete structures

The improvement of safety management in the construction sector, especially in activities for concrete structures, continues to be necessary. This paper aims at increasing understanding of everyday construction activities for building concrete structures in order to improve resilient safety management. The Functional Resonance Analysis Method (FRAM) has been applied to these activities for this purpose. Analysis of available documentation, on-site interviews and observations have been conducted to collect data. The FRAM analysis revealed that the construction phase health and safety plan is rarely used, that organizational pressure affects safety and that leading indicators to monitor normal work are not used. In addition, delivery of concrete on site and crane operations as key factors due to their influence on variability. This study outlined the potential of the FRAM model as the basis of in-depth and systematic analysis of daily performance, highlighting issues that, until now, had been undervalued.

Dispatching policy evaluation for transport of ready mixed concrete

Abstract Process of ready mixed concrete (RMC) delivery is an example of multi-objective optimization due to the conflicting objectives of the parties involved. In order to face this problem, discrete event simulation model of the delivery process is created with input parameters based on the surveyed data of real processes. The model is simulated with different vehicle dispatching policies and the results are analysed focusing on performance indicators. The research results compared in terms of Pareto optimality indicate that employing effective dispatching strategies can reduce both site idle time and waiting time of vehicles.

Risk management in the organization of delivery of construction materials

In the article, the authors consider the problem of identifying and assessing the risks that arise when organizing the delivery of construction goods using the example of one of the main materials - concrete mixture for transport and civil construction facilities. The relevance of this topic is due to the complexity and dynamism of the concrete mixture delivery system, during the functioning of which the emerging risks directly affect the quality of the supplied concrete mixture and technological processes. In this regard, the FMEA calculation and analytical method is propose, adapted to identify risks in the concrete mixture delivery system, which allows you to assess the criticality and significance of each identified type of risk (failure). Accounting, analysis and risk assessment constitute the toolkit of the risk management system - risk management - aimed at increasing the efficiency of business processes by reducing the likelihood of adverse events and minimizing possible losses. At the same time, risk management is directly relate to making management decisions, often in conditions of uncertainty. Thus, risk assessment and risk optimization is an important and complex task.

Organisation, management and optimisation of ready mixed concrete delivery for commercial batching plants of Western India

This paper is an attempt to organise, manage and develop a delivery schedule model with real time data for a commercial ready mixed concrete (RMC) plant in Ahmedabad city of Gujarat in Western India. Without a proper delivery schedule, either a truck-mixer would need to wait for the concrete to be placed at site or the construction site would need to wait for the truck-mixer to arrive on time. It has been observed after 101 iterations in MATLAB software that the dispatch scheduling sequence 1, 2, 2, 1, 1, 3, 2, 3, 2, 3, 3, 3 has the least total waiting time of 155.4 minutes. After validating the same model with real time data, it has been observed that for the above dispatching sequence, the total waiting time is 153 minutes with one obstruction resulting in a delay of 48 minutes for the casting of concrete at site. Furthermore, based on the computations, it is recommended that the plant authorities need to increase the number of RMC truck-mixers from five to seven for uninterrupted and smooth delivery of RMC from plant to site.

Organisation, management and optimisation of ready mixed concrete delivery for commercial batching plants of Western India

Organisation, management and optimisation of ready mixed concrete delivery for commercial batching plants of Western India

Optimization of ready mixed concrete delivery for commercial batching plants of Ahmedabad, India

This paper is an attempt to develop a delivery schedule model with real time data for a commercial ready mixed concrete (RMC) plant in Ahmedabad city of Gujarat, India. Without a proper delivery schedule, either a truck-mixer would need to wait for the concrete to be placed at site or the construction site would need to wait for the truck-mixer to arrive on time. Developing an optimized dispatching and delivery sequence scheduling would improve the dispatching order of delivery of the RMC through truck-mixers from commercial batching plants to the respective construction sites. In the present research, this problem has been addressed through optimization techniques developed through mixed integer programming. Mixed integer programming considers both discrete and continuous variables which affect the delivery of RMC to the respective construction sites. The delivery scheduling problem was defined by identifying the objective function and the associated constraints. The mixed integer programming code was written with the help of MATLAB software. It has been observed after 101 iterations in MATLAB software that the dispatching sequence 1,2,2,1,1,3,2,3,2,3,3,3 has the least total waiting time of 155.4 min. After validating the same model with real time data, it has been observed that for the above dispatching sequence, the total waiting time is 153 min with one obstruction resulting in a delay of 48 min for the casting of concrete at site. Furthermore, based on the computations, it is recommended that the plant authorities need to increase the number of RMC truck-mixers from five to seven.