Concrete Pump Research Articles

Determination of Lubrication Layer Thickness and Its Effect on Concrete Pumping Pressure.

The flow of six kinds of fresh concrete under different flow rates and lubrication layer thickness (TLL) values in the horizontal pipe was numerically simulated. The influence of the TLL on the pressure per unit length (PL) was analyzed. It was determined that the formation of the lubrication layer (LL) significantly reduces the PL in concrete pumping. As the TLL increased, the PL decreased. However, the degree of reduction in the PL gradually decreased as the TLL increased. Relating the simulated PL with the experimental PL, the size of the TLL was obtained, which was between 1 and 3 mm. The minimum and maximum were 1.23 and 2.58 mm, respectively, and the average value was 1.97 mm. The strength (S24, S50), the size of the aggregate (A10, A20, A25), and the flow rate of pumping all affected the TLL. The type of fresh concrete and the flow rate of pumping significantly affected the PL, which impacted the TLL. However, the TLL also impacted the PL. Finally, this made the TLL change within a certain range. When PL > 14,000 Pa/m, 2 mm < TLL< 3 mm; on the other hand, 1 mm < TLL< 2 mm. Therefore, we can use CFD to simulate the flow of all types of concrete in the actual pumping pipeline with a TLL of 2 mm to obtain their pumping pressure and guide the actual construction.

Q-learning improved golden jackal optimization algorithm and its application to reliability optimization of hydraulic system

To endow the prey with intelligent movement behavior and improve the performance of Golden Jackal Optimization (GJO), a Q-learning Improved Gold Jackal Optimization (QIGJO) algorithm is proposed. This paper introduces five update mechanisms and proposes double-population Q-learning collaborative mechanism to select appropriate update mechanisms to improve GJO performance. Additionally, a new convergence factor is incorporated to enhance convergence capability of GJO. QIGJO demonstrates excellent performance across 23 benchmark functions, CEC2022, and three classical engineering design problems, indicating high convergence accuracy and significantly enhanced global exploration capability. The reliability optimization model of the hydraulic system for concrete pump trucks was established based on a Continuous-time Multi-dimensional T-S dynamic Fault Tree (CM-TSdFT), considering the two-dimensional factors of operating time and number of impacts. Utilizing QIGJO to optimize this model yielded excellent results, providing valuable methodological support for reliability optimization of hydraulic systems.

METODE PELAKSANAAN PEKERJAAN PIERHEAD PADA PROYEK PEMBANGUNAN JEMBATAN CIKERUH DI JALAN RAYA CIBOLERANG KECAMATAN JATIWANGI KABUPATEN MAJALENGKA

ABSTRAK One of the important structures in the maritime industry, the pierhead construction used for various functions such as loading and unloading ships, stackinggoods, and other logistics activities. Hence, the construction of the pierhead requires careful planning and execution to ensure that the structure is strong, safe, and complies with safety standards and regulations applicable. The aim of carrying out this practical work is to know what is the process and method for implementing pierhead work on the project construction of the Cikeruh bridge on the Ciborelang highway, Jatiwangi District Majalengka Regency, know what tools and materials are used in carrying out pierhead work and how to care for the concrete. In the method of carrying out pierhead work there are eight stages work includes Preparatory Work, ringlock installation, Installation of working floors, concrete work, installation of formwork, pierhead casting, formwork dismantling and concrete maintenance. As for the tools used in carrying out the work Pierheads include: excavators, dump trucks, truck mixers, concrete pumps, pipes tremi, concrete vibrator, air compressor, wood cutting tool, crane, generator generator, hand tools, hand saws, wire cutters and electric drills. Meanwhile, the materials used in carrying out pierhead work namely using FC'40 concrete, reinforcing steel, 3x3 angle cast stop, ringlock, concrete decking, plywood coated with 1 side polyfilm (12 mm and 9 mm thick), profile steel or holow and wood (size 5/7 and 4/6), scaffolding, formwork oil andtie road.

The One-Dimensional Flow Pressure Loss Correction Model Based on the Particle Flow through Concrete Bend

The rheological behavior of concrete pumping in the bend section is complex. The existing conversion calculation for pumping pressure loss based on the straight pipe section often fails to meet engineering precision requirements. This paper develops a pressure loss correction model for a concrete pumping bend section based on a new one-dimensional flow model for the straight pipe section simulation of particle flow; the study analyzes the impact of parameters such as elbow shape and pumping flow rate on pressure loss. An equivalent conversion relationship between the bend section and the straight section is established. The comparison with the measured pressure values from the project shows that the relative error between the pressure loss values calculated by the correction model and the actual measurements is 15.8%.

Practical Insights and Advances in Concrete Pumping

This technical letter gives a concise overview of the state-of-the-art in concrete pumping. It outlines the different pump systems, briefly describes the general flow behavior of concrete in pipes, and addresses the main challenges of pumping. It also elaborates upon factors influencing the pumping behavior and how to control the pumping process.

Implementation of Lean Construction to Reduce Waste with the Value Stream Analysis Tools (VALSAT) Method in the Project Casting Process

This study aims to identify waste that occurs in the casting process of the project carried out by CV. Wishitama using value stream analysis tools (VALSAT) and provide suggestions for improvements with fishbone diagrams for the casting process of the project carried out by CV. Wishitama. This study uses a qualitative approach and case study with value stream analysis tools (VALSAT) and fishbone diagram analysis. The results of this study are that there are four types of waste that are prioritized for elimination, namely, overprocessing, defective products, queues, and motion. This study will provide new contributions to knowledge in the field of lean construction, with a focus on the construction industry. The results of this study will complement existing knowledge and provide new insights into how the application of lean construction can eliminate waste in the construction industry. Companies can eliminate and be effective in waiting for heavy equipment (readymix and concrete pumps) and vibrating equipment during casting. In addition, companies can increase direct supervision, conduct additional training, conduct evaluations, implement a reward or punishment system according to employee performance, plan efficient schedules, assign employees according to needs, and conduct outreach on current employee performance as a form of effort to improve human resources.

Effect of pumping process on the properties of 3D printed concrete containing air-entraining agent

Using 3D printing technology in the construction industry is growing rapidly due to its numerous advantages. However, understanding various influencing factors on this technique is crucial. Among these, the concrete pumping process can significantly impact printed concrete’s properties. The results indicate that the pumping process can alter the structure of void spaces, reduce the air content, and increase the compressive strength of concrete. Mainly, the mechanisms of mechanical entrapment, reduction of air content and increase of hydration kinetics respectively cause these changes in air content and compressive strength due to pumping. In the control samples, the fresh air content decreased by 47% and the compressive strength increased by 4.3%. The creation of stable air bubbles using air-entraining agents can lead to a decrease in change of air content and compressive strength. By using 0.12% air-entraining agent, the drop in air content due to pumping reached about 23–25%. It also appears that, depending on the amount of entrained air in the mixture, pumping can affect its flowability differently. Highlights The pumping process is an essential component in 3D printed concrete, so it is necessary to see the effect of this process on the properties of printed concrete, especially its fresh properties. Although the addition of an air-entraining agent can help concrete resist freezing and thawing cycles, what matters is the air content in the hardened state. Concrete pumping can change the structure of concrete voids and affect its various properties.

Simulation analysis and prevention strategies for fatigue fracture of the swivel shaft in concrete pump trucks

During the pumping operation of concrete pump trucks, the swivel shaft primarily withstands a series of complex loads such as bidirectional bending moments and torque (stemming from the self-weight of the boom in the amplitude plane, the self-weight of the concrete; wind load and rotational inertia force in the rotation plane; torque from the delivery pipe and the concrete inside), as well as lateral wind load on the concrete and the impact vibration caused by the flow of concrete. These factors can easily lead to fractures due to the loads exceeding the material load limit of the swivel shaft. This study targets the swivel shaft fracture accidents during the construction process of concrete pump trucks, hypothesizing that the accidents occur due to improper installation angles of the swivel shaft (angle between the oil channel hole and the cylinder axis). Firstly, numerical simulation of the onsite conditions is conducted and compared with the results observed from the actual accidents. Secondly, by fixing the onsite conditions (keeping the boom posture unchanged), a 360° rotational simulation calculation of the fractured swivel shaft is performed to identify the relationship between high stress intervals and the swivel shaft rotation angle and the angle between the second variable oil cylinder axis. Finally, a full-condition calculation is conducted for the boom and the swivel shaft. The results indicate that the high stress area of the swivel shaft does not change with the swivel shaft rotation angle (when the boom is fixed) but is related to the position of the second variable oil cylinder axis and is symmetrically distributed around it. Therefore, adjusting the swivel shaft rotation angle to avoid the high stress area near the symmetry axis of the second variable oil cylinder can prevent the fracture accidents of the swivel shaft.

One-Dimensional Modeling of the Pressure Loss in Concrete Pumping and Experimental Verification

An accurate formula for calculating the pressure loss in concrete pumping plays a significant guiding role in the design and service process of pump trucks. Based on the flow characteristics of concrete pumping, a straight pipe one-dimensional model for the pressure loss is developed, in which both the viscous force of the mortar in the lubrication layer and the blocking effect of coarse aggregate particles are considered. First, the complex geometrical shapes of the aggregate particles are geometrically reconstructed by using a HandySCAN noncontact scanner and the reverse modeling software Geomagic Design X (v.19.0.2). Then, the equivalent spherical size of nonspherical aggregate particles is calculated according to the equal hydraulic radius principle. The blocking effect of the aggregate particles is converted into the wall roughness. Finally, an explicit expression for the pressure loss in concrete pumping is deduced by using Modi’s equation, Bernoulli’s equation, and Darcy’s formula, and the calculated value is compared with the measured value at a corresponding experimental site. The results indicate that the pressure loss values calculated with the one-dimensional flow model are closer to the actual pumping pressure loss values. The relative error between the results and the actual pumping pressure loss value is about 20.2%.

Generation and Characteristics of Construction Noise in Rail Transit Engineering Enclosure Structures

Rail transit is an important part of the urban transportation system, while the noise generated during construction seriously affects the engineering personnel and surrounding residents. To investigate the noise emissions and characteristics during the construction of the enclosure structures in the rail transit engineering project, an empirical study is conducted through on-site surveys, semi-structured interviews, and experimental monitoring. The results indicate that during enclosure structure construction, there are nine key noise-emitting machines and four key noise-generating construction processes. Among them, the equivalent average sound levels of six machines, including pneumatic hammers, pneumatic drills, concrete pump trucks, construction drills, rotary drilling rigs, and grooving machines, exceed 80 dB(A). The energy contribution rate curves of machine spectra peak at 63 Hz, 500 Hz, 1000 Hz, and 4000 Hz, which have certain effects on construction personnel and nearby residents. Meanwhile, guide wall construction, groove construction, reinforcement cage fabrication and hoisting, and concrete pouring are identified as key noise-generating construction processes. This empirical investigation helps to establish a theoretical basis for noise control during the construction of enclosure structures in urban rail transit engineering projects, and the results provide valuable references for the formulation of auxiliary noise reduction measures.

Four-way CFD-DEM coupling to simulate concrete pipe flow: Mechanism of formation of lubrication layer

This study introduced a four-way CFD-DEM coupling approach to simulate the shear-induced particle migration (SIPM) mechanism leading to formation of the lubrication layer (LL) during concrete pumping. The CFD-DEM simulations considered the coupled effect of concentration (10 %–40 %) and wide size distribution (1–17 mm) of aggregate and rheology of the mortar for forces between the suspending matrix and the particles (and vice versa), as well as force transmission directly between particles (and the pipe wall). The formation of the LL was successfully simulated through a more realistic understanding the SIPM mechanism and rheological evaluation across the pipe with comparable calculation times compared to the one-way coupled DEM approach, especially for high concentrations. The simulated LL thicknesses of 0.8–2.7 mm compared well with experimental values. The flow rate and rheological heterogeneity of pumped concrete, and rheology of the LL, were found mostly controlled by the granular-skeleton characteristics rather than the suspending-matrix rheology.

Hardened property changes due to the pumping process of self-consolidating concrete

Pumping of self-consolidating concrete (SCC) is a vital construction technique. Curiosities are aroused by the effect of this intense physical process on the hardened properties of SCC. To examine this issue, a total of seven SCC mixtures are pumped at constant flow rates in pipelines with lengths of 324, 600, and 912 m. Parameters related to the hydration stages, air-void system, compressive strength, elastic modulus, and shrinkage at early ages are tested on specimens made of concrete before and after pumping. Results of tested samples find that the spacing factor grows, but the specific surface lessens after pumping. Also, in most cases, the compressive strength and elastic modulus decrease due to the pumping. The variations of these two factors are linearly related to the pumping distance in most cases. Additionally, the variations in the early age of shrinkage cracking show a dependency on the concrete compositions, temperature, and pumping characteristics.

Shear thickening of cementitious suspensions: effect of high-volume fraction and hydration

The lubrication layer (LL) formed at the concrete–pipe interface plays a crucial role in facilitating concrete pumping. Shear thickening in this layer significantly affects concrete pumping. However, very few studies are available for understanding the onset and intensity of shear thickening of the LL. In this study, the effect of solid volume fraction (SVF), superplasticiser dosage, supplementary cementitious materials and hydration on the shear thickening (continuous and discontinuous) behaviour of cementitious suspensions were investigated. Results show that an increase in SVF reduces the shear thickening intensity for systems using ordinary Portland cement (OPC), whereas the intensity is amplified for systems with fly ash (FA) or ground granulated blast furnace slag (GGBS). An increase in superplasticiser dosage results in an early onset of shear thickening and increases the shear thickening intensity, regardless of the binder used. Systems including GGBS exhibit the highest shear thickening intensity, followed by OPC- and FA-based systems. Based on these results, it is evident that the superplasticiser dosage for OPC-based systems needs to be optimised based on the structural buildup, while, for FA- or GGBS-based systems, the superplasticiser dosage needs to be optimised based on shear thickening behaviour with respect to hydration.

Vibrations of the concrete pump boom in the plane of rotation

Vibrations of the concrete pump boom in the plane of rotation

Vibration-polynomial-based optimal trajectory planning for mobile concrete pumping equipment with state constraints

To improve the operating stabilities of the flexible hydraulic manipulator in concrete pumping equipment, a trajectory planning method based on optimal vibration energy is presented. First, predefined trajectories are generated by the quintic polynomial method, and kinematic inversions are established by unifying the velocity and angle constraints into the velocity level. Then, relationships between the boom vibration and the vibration energy are solved in modal space. Specifically, hydraulic actuators are regarded as spring-damping systems to calculate generalized forces into the vibration equation. The vibration equation can solve the modal coordinate and vibration model function, such that the elastic potential energy to cause vibration is completely described. Next, floating values are captured by a genetic algorithm to minimize vibration energy, and then introduced to the predefined trajectory to weaken the boom vibration. Last, the proposed trajectory planning method is verified by a concrete pumping spreader with a 13 m hydraulic manipulator.

Multi-objective optimization of concrete pumping S-pipe based on DEM and NSGA-II algorithm

In the process of fresh concrete pumping, the S-pipe plays a crucial role in the pumping system. The impact and scratching of concrete aggregate on the wall of S-pipe will cause the wear of the wall and lessen its service life. The structural design of the pumping S-pipe typically relies on experience, and the cost for experiments is too expensive. In addition, the influence mechanism of structural parameters on S-pipe wear is still unclear. In view of this, to reduce the wear of S-pipe and investigate the influence of structural parameters on the wear of S-pipe, the structural parameters of S-pipe (curvature radius r1 and r2, horizontal dimension l3, and inclination angle θ) were optimised through discrete element numerical simulation combined with the non-dominated sorting genetic algorithm-II (NSGA-II) in this paper. Firstly, the wear coefficient was determined by friction and wear test. The discrete element method (DEM) model of pumping suction unit was simplified, and the S-pipe was parameterised. Secondly, sample points and their exact values of the optimization objectives were obtained by Latin hypercube sampling (LHS) plan and DEM simulations, respectively. From these, a Kriging surrogate model was constructed. Taking the average wear rate and the maximum wear of the S-pipe as the optimization objectives, a multi-objective optimization design was performed based on the NSGA-II and the Kriging models. After optimization, a series of Pareto optimal S-pipe models were obtained. Comparing the optimised model with the original model, the average wear rate and maximum wear amount of the S-pipe were reduced by 9% and 26%, respectively.

About effect of dynamic loading caused by concrete pump on bending moments, anchor forces and deformations in single level anchored retaining wall

This paper explore effect of dynamic loading caused by concrete pump on bending moments, anchor forces and deformations in single level anchored retaining wall. Dynamic loading is obtained by using a special developed dynamic mathematical model of truck-mounted concrete pump, by means of which are calculated the maximal dynamic loadings (acceleration and forces), which are transferred from concrete pump to the soil, and from there accordingly – from soil to the retaining wall under consideration. After that is performed a detailed finite element analysis of the retaining wall, by using software product Plaxis 3D, during which are analyzed the variation of bending moments, anchor forces and deformations in single level anchored retaining wall and after dynamic loading applying. There is also a numerical example considered, for which are calculated the maximal dynamic loadings, which are transferred from concrete pump to the soil, and from ground supports to the retaining wall. An amplification factor (dynamic factor) due to dynamic effects is calculated, by which is necessary to be multiplied the static loadings caused by concrete pump on soil. In the conclusion is made a qualitative assessment of the dynamic influence of concrete pump on the soil and the retaining wall section and ground anchor.

Sudden Changes in Workability during Concrete Pumping – An Industrial Approach

Abstract Pumping is the preferred placement method for concrete. The pumping process influences fresh properties of concrete. Competent producers handle these issues when composing the mix design. However, sudden changes in workability sometimes appear, both in the form of increased and decreased workability. Both changes might be handled on-site. However, even the situations that are sufficiently handled, cause delays and extra costs. Sometimes the final result’s quality is compromised, resulting in repairs and economic compensation claims. The extent and causes of incidents with sudden changes in workability are still to be investigated. It is suggested that around 1 100 000 m3 or 30% of concrete experience sudden change in workability annually in Norway, and that 200 000 kg of chemical admixtures is used on-site. It appears that the most relevant cause is to find within variations in the fine aggregate. Increase in workability might also be caused by lack of compatibility between superplasticiser and binding materials in low-carbon concrete, enhanced by the extra mixing process caused by the pumping process. To approach these questions, the Quality Assessment system of a medium-sized Norwegian concrete producer has been investigated. It comprises documentation of 1 500 000 m3 of concrete, over 10 years.

Research on rheological behavior of fresh concrete single-cylinder pumping based on SPH-DEM

In contrast to traditional approaches to simulating fresh concrete, the model applied here allows issues such as liquid phase and the motion of sub-scale particles to be considered. The rheological behavior of fresh concrete materials was investigated, and the slump test and pumping process of fresh concrete were simulated by combining the smooth particle hydrodynamics coupled with discrete element method. Based on Bi-viscosity model and Bingham model, linear and nonlinear fitting of rheometer data and the derivation equations were educing. Bi-viscosity model and the Bingham model were compared in slump test. The results show that the Bi-viscosity model is more accurate in simulation, and the error percentage is less than 10%. The Bi-viscosity model was used to simulate and predict the results of slump experiment, and the influence of rheological parameters on the slump velocity and shape was obtained. The simulation analysis model of concrete single-cylinder pumping is established, and the experimental and simulation analysis models are compared. The results show that the SPH-DEM pumping pressure prediction is very close to the experimental results.

Study on pumping wear characteristics of concrete pipeline based on CFD-DEM coupling

Concrete pumping, integral to building construction, governs pipeline durability and overall construction efficiency. This study advances the traditional methods by employing the CFD-DEM coupling technique, a pioneering approach that integrates the irregular shape of coarse aggregates, capturing the intricacies of concrete pumping in pipelines. Beyond identifying primary wear areas and quantifying wear magnitudes, this research unveils a quadratic progression in average wear over time. The most pronounced wear appears in the pipeline’s bent sections. Notably, pumping speed, more influential than aggregate volume fraction, is pivotal to pipeline wear. Minimized speeds increase blockage risks, notably at elbows, while augmented speeds intensify wear. An optimal speed range between 2 and 3 m/s is deduced. Additionally, as the aggregate volume fraction surges, wear amplifies and blockages frequent. Hence, an aggregate volume fraction between 15 and 20% emerges as the recommendation.