Lightweight Concrete Walls Research Articles

Enhancing the Use of Expanded Polystyrene (EPS) for Lightweight Concrete Wall Panels

Concrete is widely used in for construction purposes due to many advantageous properties. Depending on the density, concrete can be categorized as either conventional or lightweight. However, incorporating sustainable and eco-friendly elements like Expanded Polystyrene (EPS) can reduce the weight of concrete resulting in construction material. The main objective of this research is to investigate the effects of the inclusion of EPS towards the physical characteristics of concrete such as compressive strength, flexural strength, density and water absorption. This research also aim to analyze the soundproofing capabilities of wall panels produced using EPS. The study focuses on evaluating percentages (10%, 15% and 20%) of EPS as aggregates in terms of their impact on mechanical properties, physical properties and soundproofing qualities, in lightweight concrete. A total of 36 cube samples measuring 100 mm x 100 mm x 100 mm were prepared for testing at both 7 day and 28-day curing periods. In addition, 12 wall panel samples measuring 100 mm x 100 mm x 500 mm and another four wall panel samples measuring 600 mm x 600 mm x 40mm for analysis. Findings of the research indicate that the desired targets were met for water absorption (10%) density (15%) and soundproof performance (20%). During the 28-day strength test, the compressive strength decreased by 21.86%, 30.57% and 35.56% when replacing 10%, 15% and 20% of the material respectively. Lightweight concrete achieved a value of 19.45 MPa with a replacement of only 10% EPS. However, the samples, with a replacement of 15% and 20% did not reach this compressive strength level. This study demonstrates that EPS can be effectively utilized in applications. There was a reduction for the flexural strength ranging from 13.42% to 27.89% compared to the control mix when replacing with EPS at rates of 10%, 15% and 20%. This study succeeded in producing the novel discovery of the use of EPS in contributing to reducing overall structure weight, which in turn helps decrease energy consumption during transportation and construction processes.

A scheme of installing ALC wall panels based on autonomous mobile robot

Autoclaved lightweight concrete (ALC) wall panels are widely used in building envelope structures. Due to the limitations of their sizes and architectural environment, installing ALC wall panels is very complex, requiring significant labor and time costs. Construction robots provide enhanced efficiency, yet current façade installation robots lack comprehensive on-site automation. In this study, an on-site wallboard installation robot with sensors, a mobile base, and a mechanical gripper was self-designed. Based on this robot, an automated installation scheme with integrated functions was proposed for the multiple steps from grasping to installing the wall panel. The robot could recognize and judge the posture of the wall panel through a robot vision algorithm and was able to navigate according to the simultaneous localization and mapping (SLAM). The proposed scheme achieved good results in both simulation and field testing. The robot automatically completed multiple tasks, from grasping to placing ALC wall panels, significantly reducing the difficulty of manually installing ALC wall panels and avoiding construction hazards.

The Effectiveness of Styrofoam Mixtures in Lightweight Concrete Walls

This research explores the potential use of styrofoam concrete as a sustainable construction material with excellent acoustic properties. Considering variations in the thickness of styrofoam concrete, the study employs the NoiSee application on smartphones as an affordable and flexible noise measurement tool. The results investigate the potential of using styrofoam to reduce noise. The findings indicate that styrofoam, especially at a thickness of 4 cm, exhibits high effectiveness with a noise reduction of up to 60%. Additionally, the addition of styrofoam waste to brick mixtures can enhance the sound absorption coefficient at 800 Hz frequency. Styrofoam is effective in sound absorption below 1000 Hz, with thickness ranging from 1 cm to 3.5 cm improving sound absorption performance at various frequencies, while a thickness of 4 cm proves effective at 1000 Hz frequency. Overall, the combined results affirm the potential of styrofoam as a customizable soundproofing material for various acoustic applications.

Improving the thermal properties of lightweight concrete exterior walls

This article is devoted to the development of energy-efficient porous expanded clay concrete for exterior walls. Experimental data confirming the expediency of designing the optimal composition of porous concrete according to the general method of designing the optimal composition of the general theory of artificial building conglomerates (ABC) are presented. The presence of waste ash from thermal power engineering and a complex gas–forming agent based on the polymer K-9 reagent in the concrete provided increased durability, improved humidity and thermal engineering conditions of porous concrete.

Precast lightweight concrete wall panels from plastic waste and household ash as partially sand and cement replacement

The present study aims to investigate the properties of precast lightweight concrete wall panels prepared with the addition of plastic powder and household ash as a partial substitution for sand and cement.

Heat loss characteristics of typology-based apartment building external walls for a digital twin-based renovation strategy tool

Information about existing building structures is necessary for creating a renovation strategy. Older buildings are often built using typical building envelope structures. However, this information is presented in the building register at a general level, specifying the material type but not its characteristics. For a cross-regional reconstruction strategy, it is necessary to link the scarce information in the building register with the heat loss characteristics of the building envelope structures. In the current study, we classified external wall solutions according to building typologies and linked this with building register information. The typology database includes log, timber frame, brick, concrete, and aerated lightweight concrete external wall structures. Comparing the typology-based values and the actual situation showed that the wall structures’ expected and actual heat loss characteristics agreed. However, there were also significant deviations, primarily because the data from the building register did not allow for precise classification. Nevertheless, data showed that building typology-based heat loss properties are necessary for developing a district-based renovation strategy.

New ALC panel wall installation quality control and reinforcement measures

The rapid development of the construction industry has promoted the emergence of autoclaved aerated lightweight concrete slab wall (ALC panel wall) materials. This new type of building raw material has excellent use characteristics: its light weight, fire resistance sound insulation performance, environment protecting, economic, convenient construction and other advantages, so it has been widely used in the field of construction. For example, it can be used in all kinds of residential housing, apartments, office buildings, underground garages and other buildings in the wall enclosure construction, making the above-mentioned buildings with higher quality and practicality. In this paper, based on the analysis of the basic performance of ALC panel walls, the construction process, transport storage and technological innovation are combined to demonstrate the quality and anti-cracking control methods in the installation process of ALC panel walls, and the reinforcement measures to improve the construction efficiency of ALC panel walls, in view of the cracking and quality problems.

Shaking table tests and seismic assessment of a full-scale precast concrete sandwich wall panel structure with bolt connections

A novel, light-weight, sustainable, repairable and cost-effective precast concrete sandwich wall panel structure system is proposed in this paper, including the dry bolt connections and the precast concrete sandwich panels. To evaluate the seismic performance of precast structure system, a sequence of shaking table tests is carried on the full-scale precast concrete sandwich wall panel structure, and the dynamic characteristics, damage pattern, dynamic responses and seismic fragility are investigated and analyzed by the test results under service level earthquake, design based earthquake, and maximum considered earthquake. The seismic fragility curves and failure probability curves are analyzed by the shaking table test results, which quantitatively describes the seismic performanceexpressed by probability. The results show that the precast concrete sandwich wall panel structure performs high lateral stiffness, large safety margins and high strength reserves. The precast concrete sandwich wall panel structure system presents a good seismic performance. The damage of the structure is slight under maximum considered earthquakes, and the structure has begun to enter the plastic stage. The light-weight characteristic reduces the dynamic responses, and the mild sliding between precast components consumes a fraction of seismic energy.

Experimental study on the seismic performance of steel frames with infill ALC wall panels

To explore the seismic performance of H-shaped steel frames with infill precast autoclaved lightweight concrete (ALC) wall panels, the horizontal low-cyclic loading tests were conducted under vertical load. The influence of the connector style, the arrangement, and the integrity of the wall panels on the seismic performance of the structure were analyzed depending on four specimens of H-shaped steel frames with ALC wall panels and one hollow H-shaped steel frame. The failure mode, bearing capacity, rigidity and strength degradation, and energy dissipation performance were compared and discussed. The results showed that the steel frame with infill wall panels had better ductility and energy-dissipating capacity than the hollow frame. The infill ALC wall panels greatly enhanced the seismic performance of the frames and had a significant influence on the bearing capacity, stiffness, energy dissipation capacity, and ductility performance of the specimens. The maximum ductility factors and total energy dissipation of the steel frame with ordinary infill wall panels were 1.58 times and 2.27 times larger than those of the hollow frame. Due to cooperation with the steel frame, the panels delayed the buckling and in-plane deformation of the frame. The sliding connector improved the bearing capacity, displacement ductility, and energy dissipation of the overall structure compared with the hooking connector. Moreover, the bearing capacity of the frames with the reinforced wall panels was improved further. Additionally, the equivalent compression bar model was developed to estimate the bearing capacity of the steel frames with the infill ALC wall panels. The experimental conclusions and the proposed analytical model improve the practical design of the steel frames with the infill ALC wall panels in high-rise buildings.

Fire Resistance of an Assembled Integrated Enclosure Panel System

Due to increasing economic development in recent years, large-scale prefabricated structures have been used for substations. However, the assembly of steel structures suffers from technical problems, such as the mismatch between the fire protection level of the main structure and the enclosure system. This paper proposes an assembled integrated enclosure panel system for covering and fireproofing steel structures, such as beams and columns, consisting of sandwich wall panels and autoclaved lightweight concrete (ALC) wall panels covering the main steel structure. Fire resistance tests were carried out for each part and the entire integrated enclosure panel system to fully investigate its fire resistance performance. ALC and gypsum were selected as the external fire protection materials for the sandwich wall panel test for theoretical analysis and fire resistance test. The fire resistance test results show that the designed solutions of sandwich wall panels and ALC panels covering steel beams and columns meet the fire protection requirements of the ISO-834 standard fire test. The proposed size scheme of the integrated enclosure panel system is an integrated sandwich wall panel composed of 50 mm thick ALC board + 50 mm thick rock wool layer + 50 mm thick ALC board and the integrated structure of 100 mm thick ALC board covering beams and columns. The designed U-shaped connectors between the wall panels are suitable for the assembled integrated enclosure panel system.

Use of bauxite tailing for the production of fine lightweight aggregates

The prediction of bloating of lightweight aggregates (LWA) made from waste materials according to the chemical composition of raw material does not provide a good fit with existing theories. To explain the pore formation of LWA more accurately, it is necessary to consider the effect of initial voids due to gas release before the generation of the liquid phase. This study utilized the bauxite tailing and silica fume as raw material and a two-step firing method to produce fine LWA. The basic properties and microstructure of LWA were evaluated. The experimental results showed that bauxite tailing and silica fume played different roles in the pore formation of LWA. Bauxite tailing can provide gas-generating components related to the initial voids. Silica fume can promote the generation of the liquid phase associated with the development of closed pores. The LWA produced from bauxite tailing and silica fume had a bulk density of 931–1100 kg/m3 and water absorption of 1.2–16.6%, which met the specification standard for LWA. Silica fume of above 20% and sintering temperature of above 1100 °C could produce LWA applied in lightweight concrete and insulation wall panels, while silica fume of below 20% and sintering temperature of below 1100 °C could produce LWA for internal curing. In a word, it was possible to achieve the bloating of LWA by controlling the amount of gas released using the two-step firing method. Introducing the concept of initial voids can lead to the successful design and production of functional LWA having desirable engineering properties for different industrial applications.

Thermal Optimization of Additively Manufactured Lightweight Concrete Wall Elements with Internal Cellular Structure through Simulations and Measurements

Combining the additive manufacturing (AM) process of extrusion with lightweight concrete, mono-material but multi-functional elements with an internal cellular structure can be created to achieve good thermal performance of a wall at low resource consumption. The aim of this paper is to analyze and optimize the actual thermal performance of such a component. A sensitivity analysis and a parametric optimization were conducted based on a mathematical description of heat transfer in cellular structures. To investigate the thermal performance, 2D and 3D heat transfer simulations were used and validated by heat flux measurements on an existing prototype. A geometric optimization led to a further reduction of the U-value by up to 24%, reaching 0.58 W/m2 K. The ratio of solid material to air inside the cells (relative density) was identified as the main driver, in addition to cell diameter, cell height, and cell wall thickness. The comparison of analytical and numerical results showed high correspondence with deviations of 3–10%, and for the experimental results 25%. These remaining deviations can be traced back to simplifications of the theoretical models and discrepancies between as designed and as built. The presented approach provides a good basis for optimizing the thermal design of complex AM components by investigating practical thermal problems with the help of 2D and 3D simulations, and thus offers a great potential for further applications.

Cycle Performance of Aerated Lightweight Concrete Windowed and Windowless Wall Panel from the Perspective of Lightweight Deep Learning.

This paper aims to explore the seismic mechanical properties of newly developed fabricated aerated lightweight concrete (ALC) wall panels to clarify the interaction mechanism between wall panels and structures. It first introduces the lightweight deep learning object detection algorithm and constructs a network model with faster operation speed based on the convolutional neural network. Secondly, combined with the deep learning object detection algorithm, the quasi-static loading system is adopted to conduct the repeated loading test on two fabricated ALC wall panels. Finally, the hysteresis load-displacement curve of each test is recorded. The experimental results show that the proposed deep learning algorithm greatly improves the operation speed and compresses the model size without reducing the accuracy. The lightweight deep learning algorithm is applied to the study of the slip performance of the wall plate. The pretightening force of the connecting screw characterizes the slip performance between the wall plate and the structural beam, thereby affecting the deformation response of the wall plate when the interstory displacement increases. The hysteresis curve of the ALC wall panel has obvious squeezing effect, indicating that the slip of the connector can unload part of the external load and delay the damage of the wall panel. The skeleton curve suggests that the fabricated windowless ALC wall panel has higher positive and negative initial stiffness and bearing capacity than the fabricated windowed wall panel. However, the degradation analysis of the stiffness curve reveals that the lateral stiffness deviation of the fabricated windowless ALC wall panel is more obvious. It confirms that the proposed connection method based on the lightweight deep learning model can improve the seismic performance of ALC wall panels and provide reference for the structural analysis of embedding fabricated ALC wall panels. This work shows the important practical value for exploring the application effect of embedded ALC wall panels.

Thermal Performance and Energy Efficiency of Different Types of Walls for Residential Building

Decrement factor and time lag play an essential role in determining the thermal performance of a building envelope. Building walls, which form a major part of a building, have great influences on the energy consumption and indoor environment of a room. The indoor temperature considerably increases as the outdoor temperature increases. This scenario leads to excessive reliance on the mechanical cooling system, thereby increasing energy consumption. Therefore, this study aims to investigate the thermal performance and energy efficiency of different wall types. A building with a built-up area of 387.85m2 with six different wall materials is modelled and inputted in Energy Plus simulation software as an Intermediate Data Format file. The maximum and minimum surface indoor and outdoor temperatures are then obtained to determine the thermal performance of the wall material in terms of time lag and decrement factor. The energy efficiency of the wall materials is investigated by obtaining the annual cooling energy of the building made up of different wall materials. Results show that with the time lag of 1 hour, decrement factor of 0.86, annual cooling energy load of 9.52 GJ and cost consumption of RM 608.12, aerated lightweight concrete wall is the most suitable material amongst the six wall materials.

Developing of lightweight concrete sandwich wall panels with good thermal insulation properties for sustainable buildings

This research study aims at developing and investigating the mechanical and thermal properties of lightweight sandwich wall panels with good thermal insulation properties to reduce electric power for cooling of buildings. Within this study, several thermal insulation sandwich wall panels with two outer lightweight concrete layers and inner expanded polystyrene layer were developed and tested. Test parameters included the type of the outer concrete layers and the effect of using glass fiber reinforced polymer (GFRP) shear ties to connect the outer layers. Different ratios of polystyrene beads and vermiculite aggregates (53, 68 and 84% by volume of the natural coarse aggregates) were used to replace the natural coarse aggregates in the two outer concrete layers for better insulation properties and to develop lighter panels. Test results showed that using the GFRP shear ties was effective to connect the two outer layers of the panels. The results also revealed that increasing the amount of the polystyrene beads and the vermiculite aggregates decreased the thermal conductivity, the density, and the compressive strength of the panels. These values ranged from 0.41 to 0.25 W/m.K, 596 to 486 kg/m3, and 4.21 to 2.02 MPa respectively, for the panels with polystyrene beads. For the panels with vermiculite aggregates, these values were 0.46 to 0.34 W/m.K, 646 to 626 kg/m3, and 3.14 to 1.96 MPa, respectively. The results showed that the panels with polystyrene beads were stronger, lighter, and had better thermal properties. Using the developed panels will help to reduce the self-weigh of buildings resulting in smaller structural elements. In addition, the excellent thermal properties of the developed panels are expected to reduce power consumption and develop more sustainable buildings.

Lateral load bearing characteristics of light gauge steel and lightweight concrete shear walls

In China, there is a new structural system named light gauge steel and lightweight concrete (LSLC) structure, which used lightweight concrete as structural material in composite way with cold-formed steel. Here, the shear walls are the main structural members for the LSLC structure, which are assembled with the light gauge steel lattice columns and horizontal braces, and filled with lightweight concrete. In this study, the LSLC shear walls are experimentally investigated to evaluate their failure mechanism and lateral load bearing capacity. For this purpose, several specimens with different shear span ratio are designed and tested under static cyclic loading. This paper presents the damage state and hysteresis loops of the specimens detailly. Then, the lateral load bearing characteristics of the LSLC shear walls are discussed according to the failure mechanism, such as shear and flexural failure. Finally, the calculation methods of lateral strength for the LSLC shear walls are proposed based on the diagonal strut mechanism and sectional force equilibrium.

Numerical analysis of lightweight concrete wall panels having a variation of dimensions and openings that were subjected to static lateral loads

Wall panels are non-structural parts of buildings that are considered dead loads. The mass of wall panels must be reduced to minimize earthquake risk and enhance structural resistance to lighter dead loads. This study used wall panel models that consisted of lightweight foamed concrete materials containing expanded polystyrene. The wall panels used in this study also had a variety of dimensions and reinforcements. The effect of openings on wall panel model performance was also investigated. This study aimed to analyze the performance of lightweight concrete wall panel models under static lateral loads applied until the ultimate condition. It was found that the load-deformation relation performs varying values of stiffness, strength, and ductility depended on the wall panel dimensions, reinforcements, and openings. A wall panel model with a height of 1000 mm that had length of 1500 mm and thickness of 60 mm with wire mesh and without openings achieved the highest ultimate stiffness and strength. The highest ductility was achieved by a wall panel model with openings, without wire mesh, with height, length, and thickness of 1500 mm, 1500 mm, and 40 mm, respectively. Diagrams of the deformations in this paper reflect the compressed and tensioned areas. The lefthand parts of all wall panel models without wire mesh were tensioned and had concentrations of deformation in those areas. The existence of openings also caused increased deformation due to less stiffness in the wall panel models.

Behaviour of Lightweight Concrete Wall Panel under Axial Loading: Experimental and Numerical Investigation toward Sustainability in Construction Industry

Awareness of sustainability in construction has led to the utilization of waste material such as oil palm shell (OPS) in concrete production. The feasibility of OPS as alternative aggregates in concrete has been widely studied at the material level. Meanwhile, nonlinear concrete material properties are not taken into account in the conventional concrete wall design equations, resulting in underestimation of lightweight concrete’s wall axial capacity. Against these sustainability and technical contexts, this research investigated the buckling behavior of OPS-based lightweight self-compacting concrete (LWSCC) wall. Failure mode, load-deflection responses, and ultimate strength were assessed experimentally. Numerical models have been developed and validated against experimental results. Parametric studies were conducted to study the influence of parameters like slenderness ratio, eccentricity, compressive strength, and elastic modulus. The results showed that the axial strength of concrete wall was very much dependent on these parameters. A generalized semi-empirical design equation, based on equivalent concrete stress block and modified by mathematical regression, has been proposed. The ratio of average calculated results to test results of the proposed equation, when compared to ACI 318, AS 3600, and Eurocode 2 equations, are respectively improved from 0.36, 0.31, and 0.42 to 0.97. This research demonstrates that OPS-based LWSCC concrete can be used for structural axial components and that the equation developed can serve a good guideline for its design, which could encourage automation and promote sustainability in the construction industry.

Fire Resistance of Steel Connectors of Precast Lightweight Concrete Walls

In this study the fire test was performed to investigate the mechanic behaviors and failure patterns of precast normal weight concrete (NWC) and lightweight concrete (LWC) walls with three types of commonly used steel connectors, namely dry (61), wet (81), and bearing (56E) connectors. For the LWC wall specimens, on lateral application of tension, the cracking load values of the dry, wet, and bearing-type connectors were 95.1%, 86.3%, and 83.0%, respectively, of the original loads, and their ultimate load values were 81.6%, 90.7%, and 85.0%, respectively, of the original. In the shearing test after the fire resistance test, the cracking load value of the bearing-type connector was 88.2% of the original load. Moreover, all specimens exhibited a considerable loss in the ductility ratio after the fire resistance test. However, the hysteresis energy that can be absorbed and the seismic resistance of the LWC wall were superior to those of the NWC wall. Therefore, alt-hough the LWC and NWC walls exhibited similar failure patterns, steel connectors exhibited superior fire resistance for precast LWC walls.

Evaluation of fire performance of lightweight concrete wall panels using finite element analysis

PurposeIn this study, the insulation fire ratings of lightweight foamed concrete, autoclaved aerated concrete and lightweight aggregate concrete were investigated using finite element modelling.Design/methodology/approachLightweight aggregate concrete containing various aggregate types, i.e. expanded slag, pumice, expanded clay and expanded shale were studied under standard fire and hydro–carbon fire situations using validated finite element models. Results were used to derive empirical equations for determining the insulation fire ratings of lightweight concrete wall panels.FindingsIt was observed that autoclaved aerated concrete and foamed lightweight concrete have better insulation fire ratings compared with lightweight aggregate concrete. Depending on the insulation fire rating requirement of 15%–30% of material saving could be achieved when lightweight aggregate concrete wall panels are replaced with the autoclaved aerated or foamed concrete wall panels. Lightweight aggregate concrete fire performance depends on the type of lightweight aggregate. Lightweight concrete with pumice aggregate showed better fire performance among the normal lightweight aggregate concretes. Material saving of 9%–14% could be obtained when pumice aggregate is used as the lightweight aggregate material. Hydrocarbon fire has shown aggressive effect during the first two hours of fire exposure; hence, wall panels with lesser thickness were adversely affected.Originality/valueFinding of this study could be used to determine the optimum lightweight concrete wall type and the optimum thickness requirement of the wall panels for a required application.