Concrete Mixer Trucks Research Articles

To Analysis the Meritorious Advantages of Precast Structure over Cast In Situ Building Construction In Allied With Time And Cost At Mumbai Region

Most construction projects use cast-in-place concrete, in which the wet mixture is poured andformed directly at the construction site. Since this often takes place on a construction site, the term sitecast concrete has become the standard. An analogy is drawn to the usage of precast concrete, in whichpieces are cast off-site and then transported to the construction site. Concrete for on-site casting isoften delivered using the iconic revolving-barrel concrete mixer trucks. In a centralized batching plant,where stricter quality control over the components may be maintained, the mixture is prepared. At everystage of the process—from transport to the site to proper mixing in the truck to unloading anddepositing in the forms and handling for placement, finishing, and curing—the level of responsibility andcompetence exercised by the people involved is vital. Extreme steps may need to be taken to ensureclose monitoring of each stage of production if accessibility and weather at the work site have a majorinfluence on the quality of the work. While the focus here is not on construction management orprocedures, a basic understanding of these topics would aid in the creation of workable designs forconcrete buildings. Cast-in-place concrete and precast concrete are two competing constructiontechniques supplied by various contractors for the structural elements, and a breakeven formula isestablished to help evaluate and pick the best solution. The criteria for selection is the one that will havethe least financial impact. The quantity of works, in this case concrete, is taken into account apart fromother factors. Finding that the transportation and shifting cost of Precast components significantlyimpacted the entire cost of construction, this research aims to help decision-makers and engineersanalyze both concrete building approaches early in the construction planning stage.

Analysis of the control and measurement system in terms of its application in concrete mixer trucks

Analysis of the control and measurement system in terms of its application in concrete mixer trucks

Resistência à penetração de cloretos em concretos produzidos com agregado miúdo reciclado e sílica ativa

Abstract The use of by-products and recyclable materials in the production of concrete has become an interesting alternative to mitigate environmental impacts, especially those generated by the construction industry, as long as their mechanical and durability properties do not early compromise the service life of the structures. The resistance of concrete to the penetration of harmful agents, such as chloride ions, is an important property since it directly correlates with the performance, integrity, and durability of reinforced concrete structures. This study evaluate four concrete mixes were cast for aggressiveness class III of NBR 6118 [1] produced with 8% of partial replacement of Portland cement with silica fume, resulting of metallurgical production, and with 30% partial replacement of natural fine aggregates by recycled fine aggregate from fresh concrete waste, obtained from the concrete production process in concrete mixer trucks. At 28 days of age, the specimen was submitted to capillarity, mechanical resistance and chloride migration tests, according to the NT BUILD 492 standard [2]. In general, the results indicated that the proposed replacements improved mechanical properties and chloride ion penetration resistance, mainly with the incorporation of silica fume.

Repairable System Analysis Using the Discrete Weibull Distribution

In many practical circumstances, a repair can be performed when a system fails to restore to a condition before a failure. This type of repair is known as minimal repair and one of the most used models is the power law process (PLP). It is common to consider equipment failure time as a continuous variable in this model, assuming a high degree of accuracy in the measurement tool. However, in practical situations, failures are usually observed and recorded as integer numbers of time units, such as the number of days and hours, indicating a discrete process. In this study, we used a discrete Weibull distribution instead of a continuous Weibull distribution. Since both Weibull models have similar complexities, some benefits are observed in the usage of the discrete model, such as a lower standard deviation of the parameter related to the system deterioration and also a lower Akaike's information criterion. For illustrative purposes, the use of a discrete Weibull distribution was applied to a dataset related to the failures of concrete mixer trucks. Moreover, an approach using a Markov chain with discrete states to obtain the average number of failures and the respective optimum maintenance policy was included. Additionally, six cases (found in the literature) fitted by the PLP model were reanalyzed and compared under the discrete model perspective.

Effect of using wastewater from the ready-mixed concrete plant on the performance of one-part alkali-activated GBFS/FA composites: Fresh, mechanical and durability properties

Water scarcity is the world's most pressing issue, as concrete batching facilities and concrete mixer trucks produce massive amounts of wash water every day. Recycling waste water from ready-mix concrete factories' concrete washing water is critical for conserving hundreds of millions of tons of water and preventing water and soil contamination. This study examined the impact of waste washing water on the microstructural, durability, fresh, and mechanical characteristics of one-part alkali-activated ground blast furnace slag (GBFS)/fly as (FA) composites (AAC) containing partial and complete replacement of tap water under ambient conditions. GBFS was used as the main binder in the production of AAC. FA was also used as a binder at 0%, 25%, and 50% instead of GBFS. Sodium metasilicate (MS) was used as a one-part activator at two dosages 7.5% and 15% of the total binder. The fresh properties (setting time and flowability), physical properties, compressive and flexural strength (3, 7, 28, 90, and 180 days) and durability (high-temperature resistance, freeze, and thaw resistance, drying shrinkage, sorptivity, HCl and MgSO4 resistances, NaCl effect and alkali-silica reaction) and microstructure analysis were investigated. The findings showed that the use of wastewater (WW) instead of tap water (TW) contributed positively or had no serious negative effect on the mechanical and durability properties of AAC. Compressive strength of 72.37 MPa and 81.67 MPa was gained with the inclusion of 50%WW at 7.5 and 15 %MS content respectively. The findings showed that WW improved the workability of fresh ACC containing FA, reduced dry shrinkage and sorptivity of ACC with 15%MS content, and refined the pores of hardened ACC. The results also supported that WW contributed to the decrease in expansion due to ASR and sulfate expansion. Using WW improved the high temperature and F-T resistance of ACC mixtures containing 15%MS content.

Statistical Analysis of the Chemical Composition of Concrete Slurry Waste: A Case Study of Sedimentation Tanks from Concrete Batching Plants in Manaus-Brazil

Concrete slurry waste is a material removed from sedimentation tanks that receive water used to wash concrete mixer trucks and patios of concrete batching plants (CBP). The objectives of this study were to determine the chemical composition of this residue from three different producers, in three consecutive months and at different collection points using wavelength dispersive X-ray fluorescence, investigate the inconstancy of content through analysis of variance, compare the qualitative and quantitative results with the literature and discuss the possibility of inserting the material in the proposal of different authors. Twenty-two oxides and elements were identified; among them, five showed their incidence in a punctual way. The analysis of variance showed that there are significant differences in the concentration of components between batching plants, months and collection points. The comparison with the literature showed that CaO, Al2O3 and SiO2 are the majority, both in the samples under study and in the samples from different authors. However, the average amounts of CaO are higher in the waste sludge from the concrete batching plants in question and, consequently, if this material were reused in the same proposals as the authors, the products would possibly present different characteristics and performance.

A Bi-Level Programming Model for the Integrated Problem of Low Carbon Supplier Selection and Transportation

In this paper, we investigate an integrated problem of low-carbon supplier selection and transportation. The supplier selection decision depends on the location and energy consumption level of batching plants at the manufacturing stage. Meanwhile, ready-mixed concrete is allocated and delivered to construction sites by concrete mixer trucks at the transportation stage. A bi-level programming model for the integrated problem is established. The bi-level optimization problem is transformed into a single-level problem by KKT (Karush–Kuhn–Tucker) optimality conditions. In order to validate the proposed model, a case study is conducted based on real-world problems. Experimental results show that the proposed method efficiently solves the integrated problem and the model can not only reduce carbon emissions but also optimize transportation time.

Feasibility Study of Reusing Wash Water and Steel Fibre Simultaneously on Workability, Mechanical Properties and Fracture Toughness of Concrete

ABSTRACT Water scarcity is the world’s challenging issue, and every day huge amounts of wash water(W) are produced by the concrete batching plants and concrete mixer trucks. Therefore, wash water reuse can be a method of saving water. This experimental work was conducted to determine the feasibility of using wash water in normal concrete and fibre(F) reinforced concrete. Workability and compressive, tensile, and flexural strengths, as well as fracture toughness of concrete specimens, were carried out according to ASTM and BS. The slump test results showed a slight decrease while using wash water or steel fibre and using both of them concurrently. Using wash water instead of tap water increased compressive strength at 7,14 and 28 days. Adding steel fibre in the specimens containing tap water raised compressive strength sharply at all periods. Nevertheless, applying wash water and steel fibre instantaneously in the concrete sample decreased compressive strength. This consequence was confirmed by the SEM image. Both tensile and flexural strength increased while using wash water instead of tap water. The maximum tensile strength was observed when 100% wash water and steel fibre (W + F) were replaced by tap water. Using steel fibre for concrete samples using tap water increased flexural strength by around 14% compared to the control sample. The highest flexural strength was reached while 100% wash water and steel fibre (W + F) were used simultaneously. Substituting wash water with tap water increased fracture toughness, and adding steel fibre to the concrete sample applying tap water similarly raised fracture toughness compared to the control sample. While using wash water and steel fibre in the concrete sample instantaneously, the fracture toughness increased by 49%.

Structural design of spiral blade of concrete mixer truck

This article takes a concrete mixer truck actually produced by an enterprise as an example. According to the functions of the three-part spiral blades of the front cone, cylinder, and tail of the mixing drum, combined with theoretical knowledge, the Pro/E software is used to realize the re-realization of the blade spiral. design. A spiral line that is more in line with actual working conditions is derived, which provides a theoretical basis for the design and modeling of spiral blades of concrete mixer trucks.

Influence of concrete mixer washing waste water on the chemical and mechanical properties of mortars

The world's population will be facing water shortage problems by 2050. Recycling and treatment of residual water and reusing it in real life applications may help to solve this problem. However, the total cost of the treatment processes is estimated to be very high. The reuse of concrete mixer washing waste water without previous treatment may contribute to a significant reduction in the cost associated with the treatment process. This process may also reduce the consumption of drinking water, which is used by default in concrete fabrication and for washing purposes in concrete plants. This research paper studies the feasibility of reusing washing water of concrete mixer trucks without treatment to fabricate cementitious matrices and evaluates its influence on their chemical and mechanical properties. An experimental program was conducted by using 3 different types of waste water from washing concrete mixer trucks. The hydration kinetics of cement pastes was evaluated by isothermal calorimetry. Mortar workability was studied by the consistency index. The properties of mortars in the hardened state were evaluated by determining their porosity, tensile and compressive strength. Results showed that the waste water did not significantly influence the hydration kinetics nor the properties of the fresh and hardened state of mortars, indicating its possible use as mixing water to produce cement mixtures with no previous treatment. This research presents a promising sustainability key either for elimination of treatment cost or for water shortage that threatens many regions in the world.The following specific conclusions may be derived from the results obtained in this experimental program:

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.

Predicting the capacity of an off-road self-loading drum mixer with different concrete consistencies through three-dimensional fluid dynamics analysis

The design features of machinery for concrete production are closely connected with the maximum volume capacity of processed material. Regarding the design of off-road concrete mixer trucks, there are many key parameters that define the final capacity, for example the geometric dimensions, the rotational speed and the concrete consistency. This paper presents a numerical investigation of an Eulerian–Eulerian multiphase CFD model applied to an off-road self-loading concrete truck mixer, which simulates the maximum concrete capacity by varying the concrete consistency. The calibration is performed by matching the maximum capacity of a commercially available drum, under different concrete consistency classes, with the yield stress value of the non-Newtonian Bingham model applied to the rheological properties of the simulated fresh concrete. This model can be used for the design of new concrete mixers, in order to predict the maximum capacity of the drum under different conditions and geometric design aspects. This work intends to highlight the calibration method and the numerical Bingham values applied to fresh concrete, in order to quantify concrete drum capacity while changing the fresh concrete consistency.

Reuse of fines from ready-mix concrete washing slurries

Concrete waste slurries coming from the washing of concrete mixer trucks in the manufacture of ready-mix concrete generate high costs and environmental impacts. In this work, we examined the consumption of raw materials, water, and generation of wastes for three Brazilian ready-mix concrete plants (that used different waste management strategies). The reuse of concrete slurry fines was also investigated in new concretes considering the waste management scenarios, production and operational costs. The strategy to recover fresh concrete provided the best scenario since it reduced significantly operational costs, despite the inclusion of new production cost, i.e. the hydration stabilizer additive. The replacement of sand with 1 vol.% concrete slurry provided adequate rheological conditions for concretes, when the water content increased up to 6 wt.% or added 0.3 % m.c. of polycarboxylate-based additive. The marginal increase in the production cost can also be compensated by the reduction of the disposal operational costs. The reuse strategy was not enough for the total elimination of concrete fines, requiring market diversification (e.g. pre-cast concrete products); but fines availability can be very limited.

Preliminary Human Safety Assessment (PHSA) for the Improvement of the Behavioral Aspects of Safety Climate in the Construction Industry

Occupational safety in the construction industry still represents a relevant problem at a global level. In fact, the complexity of working activities in this sector requires a comprehensive approach that goes beyond normative compliance to guarantee safer working conditions. In particular, empirical research on the factors influencing the unsafe behavior of workers needs to be augmented. Thus, the relationship between human factors and safety management issues following a bottom-up approach was investigated. In particular, an easy-to-use procedure that can be used to better address workers’ safety needs augmenting the company’s safety climate and supporting safety management issues was developed. Such an approach, based on the assessment of human reliability factors, was verified in a real case study concerning the users of concrete mixer trucks. The results showed that the majority of human failures were action and retrieval errors, underlining the importance of theoretical and practical training programs as a means to improve safety behavior. In such a context, information and communication activities also resulted beneficially to augment the company’s safety climate. The proposed approach, despite its qualitative nature, allows a clearer understanding of workers’ perceptions of hazards and their risk-taking behavior, providing practical cues to monitor and improve the behavioral aspects of safety climate. Hence, these first results can contribute to augmenting safety knowledge in the construction industry, providing a basis for further investigations on the causalities related to human performances, which are considered a key element in the prevention of accidents.

Means to Enhance Operating Efficiency of the Concrete Mixer Trucks with the Purpose of Highly-Homogeneous Concrete Mix Preparation

Option shall be considered to create concrete mixer trucks for preparation not only of high-flow but also of low-slump and dry type concrete mixes. With these aims it is offered to transfer operation to the cascade mode being characterised by combination of two principles on concrete mix preparation: gravitational and forced action.Design solution of the concrete mixer truck of gravitational-forced operation with spiral-blade shaft has allowed to liquidate available free places in the drum. The dependencies for calculation and arrangement of mix particles motion in the workspace of the machine drum are provided. Graphic performance confirms the absence of free zones.There is description of dependency for determining the homogeneity degree obtained on the basis of the experimental investigation findings.

Revision of Representative Truck’s Weight to Power Ratio in S. Korea

PURPOSES : The purpose of this study is to revise the weight to power ratio of the representative truck in S. Korea. So far, S. Korea has been using the unit lb/hp, and the construction machines were not considered in the evaluation of the performance of trucks. METHODS : This study was performed to recommend the use of ISO system of units, and to analyze the weight to power ratios of the representative trucks in S. Korea, including the dump trucks, concrete mixer trucks, and asphalt and concrete diffusers. RESULTS: From this study, the 85 percentile value of the weight to power ratio of the trucks in S. Korea`s was found to be 103.6 kg/kw. CONCLUSIONS : The performance standard for the representative truck has to be increased upward, considering the travel pattern of the dump trucks, concrete mixers, and asphalt and concrete diffuser trucks, travel distances, narrow area (work zone) of operation, and the saving in construction budget for climbing lane. Based on this study, the weight to power ratio of the representative truck in S. Korea could possibly be revised to 100~110 kg/kW.

Simulation Based Logistics Distribution Planning and Analysis for an Assembly Line of Engineering Machinery Products

This paper investigates the planning of the workshop logistics distribution system for an assembly line in an engineering machinery manufacturing company producing mainly concrete mixer trucks. The study covers mainly some methodologies in selecting appropriate logistics distribution mode, determining the distribution lot size and part-sets, and deciding the material packing method under some distribution batching rules. The simulation software QUEST is employed for carrying out some systematic simulation experiments and analysis, so as for finding an ideal logistics distribution scheme and improving the performance of the production logistics system.

Innovative process routes for a high-quality concrete recycling

This study presents alternative methods for the processing of concrete waste. The mechanical stresses needed for the embrittlement of the mortar matrix and further selective crushing of concrete were generated by either electric impulses or microwaves heating. Tests were carried out on lab-made concrete samples representative of concrete waste from concrete mixer trucks and on concrete waste collected on a French demolition site. The results obtained so far show that both techniques can be used to weaken concrete samples and to enhance aggregate selective liberation (that is the production of cement paste-free aggregates) during crushing and grinding. Electric pulses treatment seems to appear more efficient, more robust and less energy consuming (1–3kWht−1) than microwave treatment (10–40kWht−1) but it can only be applied on samples in water leading to a major drawback for recycling aggregates or cement paste in the cement production process.

Assessment of the recycling potential of fresh concrete waste using a factorial design of experiments

Recycling of industrial wastes and by-products can help reduce the cost of waste treatment prior to disposal and eventually preserve natural resources and energy. To assess the recycling potential of a given waste, it is important to select a tool capable of giving clear indications either way, with the least time and work consumption, as is the case of modelling the system properties using the results obtained from statistical design of experiments. In this work, the aggregate reclaimed from the mud that results from washout and cleaning operations of fresh concrete mixer trucks (fresh concrete waste, FCW) was recycled into new concrete with various water/cement ratios, as replacement of natural fine aggregates. A 3(2) factorial design of experiments was used to model fresh concrete consistency index and hardened concrete water absorption and 7- and 28-day compressive strength, as functions of FCW content and water/cement ratio, and the resulting regression equations and contour plots were validated with confirmation experiments. The results showed that the fresh concrete workability worsened with the increase in FCW content but the water absorption (5-10 wt.%), 7-day compressive strength (26-36 MPa) and 28-day compressive strength (32-44 MPa) remained within the specified ranges, thus demonstrating that the aggregate reclaimed from FCW can be recycled into new concrete mixtures with lower natural aggregate content.

Use of Aggregates from Recycled Concrete Mixer Trucks Waste in Concrete

This paper presents some of the results of an investigation on the possible applications of use of waste concrete aggregates from mixer trucks concrete productions (WCA) in concrete. The investigation has been carried out using factorial design for experimental design. For the study, the physical and mechanical properties along their durability of concrete produced with WCA were investigated and the results presented. Concrete mixtures were prepared using WCA as the replacement of natural fine aggregate at the level 10%, 20% and 30 wt.% with water/cement ratios of 0.40, 0.50 and 0.60. Properties of fresh and hardened concrete were evaluated: fresh unit weight, consistency, 7-day and 28-day compressive strength were carried out in specimens. The necessary data for establishing a mix proportion design and a quality control method are obtained using a full factorial design 32. The influence of level of WCA on the mineralogical composition has been established, and its suitability for use in a concrete application has been assessed. Empirical contour plots for the physical-mechanical properties of fresh and hardened concrete with WCA were obtained via regression analysis, which predict that as the amount of waste increases, has no or little effect on the compressive strength of concrete mixes. The results form confirmation experiments justify the prediction from the statistical approach.