Hollow Brick Walls Research Articles

Thermal performance analysis of hollow brick walls in hot and dry climatic zones

Thermal performance analysis of hollow brick walls in hot and dry climatic zones

6 Şubat 2023 Türkiye Depreminde Hasar Görmüş Betonarme Yapıların Güçlendirilmesi için Alternatif Ferrocement Paneller

Most of the reinforced concrete framed buildings commonly used in developing countries are not secure against earthquakes. Studies on seismic performance of reinforced concrete framed structures showed that; lateral stiffness often needs to be improved. In this study, in order to rehabilitate the structures, performances of ferrocement panels can be used to strengthen the existing hollow brick infill walls such that they act as cast-in-place concrete in fills improving the lateral stiffness is researched. Ferrocement panels are not only to be as light as can be carried by two people easily, but also from the low cost and usefulness against tensional and loads point of view. Previous researches results indicated that strength, stiffness, energy dissipation and story drift characteristics of the reinforced concrete framed building structures can be rehabilitated by the eco-friendly, cost effective and practically applicable seismic retrofitting technique that does not need evacuation of the building with these high-performance ferrocement panels.

High-strength AlCoCrFeNi2.1 eutectic high entropy alloy skeleton with hollow brick wall structures by selective laser melting

In this work, a hollow brick wall structure was introduced into the preparation of AlCoCrFeNi2.1 EHEA to realize a skeleton structure by taking advantage of the good castability of eutectic high entropy alloys (EHEAs) and high cooling rate of selective laser melting (SLM). The effects of processing parameters on eutectic microstructure and mechanical properties of SLM-ed AlCoCrFeNi2.1 EHEA skeletons were investigated. With increasing volume energy density (VED), the microstructure along the building direction evolved from cellular structure to the coexistence of cellular and lamellar structures. The phases in the SLM-ed AlCoCrFeNi2.1 EHEA skeletons contained BCC/B2 and FCC phases. Under the VED of 137.25 J/mm3, SLM-ed skeletons with hollow brick wall structures had a compressive strength of 241.2 ± 4.2 MPa. The mechanical properties from tensile tests exhibited a yield strength of 1349.4 ± 12.4 MPa and an ultimate tensile strength of 1529.5 ± 12.8 MPa. The superior performance of the selective laser melting method was attributed to fine grain strengthening, dislocations strengthening, and heterogeneous structure of FCC and BCC/B2. This work provides possibilities for microstructure design and performance improvement of EHEAs and expands the avenue for developing advanced high-strength lightweight structural and energy-absorbing alloys.

Experimental Research on Seismic Performance of Masonry-Infilled RC Frames Retrofitted by Using Fabric-Reinforced Cementitious Matrix Under In-Plane Cyclic Loading

Fabric-reinforced cementitious matrix (FRCM) composites, also known as textile-reinforced mortars (TRMs), represent a new advancement in structural repair and reinforcement technology. Aiming to improve the energy efficiency and seismic performance of existing buildings, this research focused on the development of an FRCM system in combination with phase change materials (PCMs) and extruded polystyrene sheets (XPS) to achieve adequate mechanical and thermal properties for reinforced concrete (RC) and masonry structures. Accordingly, the in-plane behaviour of five FRCM-strengthened RC frames with hollow-brick wall infill was tested under cyclic loading to investigate the improvement in earthquake resistance. The system was comprehensively evaluated by calculating hysteresis curves; comparing the lateral stiffness, ductility, and energy dissipation capacity; measuring the deformations of the specimens; and analysing the failure modes mechanically. Finally, it was proved that this novel integrated approach could significantly enhance the mechanical and seismic performance of masonry-infilled RC frames.

The strong influence of small construction errors on sound insulation of buildings with heavyweight concrete structure: A Portuguese case study

In order to attain an expected sound insulation in buildings, it is necessary to employ appropriated constructive solutions, but it is also fundamental to guarantee compatibility with other involved design professional fields, proper detailing of solutions and correct on site mounting. A solution with a predicted high acoustic performance may result in failure if there is no proper interconnection between other design professional areas or if execution mistakes occur, even if of very small dimension. The main objective of this technical paper is to analyse the influence of defects that typically occur in buildings, located in Portugal, resulting in very poor airborne or impact sound insulation performance. The chosen situations refer to buildings with heavyweight concrete structure, where small construction defects occurred and/or wrong decisions were taken, ending up with a large reduction on the final acoustic performance. Some of these errors, given their small size or because they occurred in hidden zones, easily passed unnoticed, on site. The defects here addressed in what refers to airborne sound insulation are related with execution of double masonry hollow brick walls, sound bridges in acoustic suspended ceilings, passage of ventilation or sewage pipes, inappropriate installation of acoustic doors, shutter boxes or windows. As for impact sound insulation, the presence of rigid connections is the main focus of the characterisation here performed.

Exploring the Cooling Potential of Ventilated Mask Walls in Neo-Vernacular Architecture: A Case Study of André Ravéreau’s Dwellings in M’zab Valley, Algeria

This study investigates the thermal performance of the ventilated mask wall used in the low-income neo-vernacular dwellings designed by André Ravéreau to cope with the warm desert climate conditions of M’zab Valley, Ghardaia, in southern Algeria. This device is a ventilated façade provided with an opaque external massive cladding. It is designed to be particularly efficient in hot climates, functioning simultaneously as a brise-soleil and a ventilated façade, compared with conventional façade systems. Based on a typical experiment conducted during the summertime (12–14 August), a residential unit in Sidi Abbaz selected as a case study was modeled and calibrated using EnergyPlus (v8.4) software, and then a dynamic simulation was performed in order to assess the efficiency of the ventilated mask wall as a cooling strategy. By means of the validated thermal model, various alternatives for the façade materials were investigated, and the thermal behavior of the current ventilated mask wall was compared with a 45 cm thick limestone façade wall, and a 30 cm thick hollow clay brick wall under the same conditions. Countless benefits were achieved by the application of the mask wall system, including a stable and less fluctuant inner surface temperature, and a reduction in the incoming summer heat flux. The improvements performed, in particular the time lag of 12 h and the related decrement factor of 0.28 indicate the effectiveness of this wall system, which enabled radiant temperature drops of more than 10 °C, and an air temperature decrease of about 6 °C, during the summer sunniest hours. The results demonstrate that this solution is suitable for buildings design applications to meet the objective of low-energy demand in warm desert climates.

Thermal performance assessment of double hollow brick walls filled with hemp concrete insulation material through computational fluid dynamics analysis and dynamic thermal simulations

Thermal insulation is the most widely used solution to reduce the energy consumption of buildings. In order to minimize the cost and time needed to build an insulated wall as well as to decrease greenhouse gas emissions, this manuscript proposes to incorporate a bio-based insulation material into the air cavities of hollow bricks constituting the external walls of buildings. Therefore, the aim of this paper deals with the assessment of the thermal performance of Moroccan external building envelope constituted of double hollow brick walls filled with hemp concrete and separated by a 5 cm air layer thickness. Three configurations composed of three types of hollow bricks were studied (8-, 12- and 16-holed bricks). Firstly, using numerical simulations based on a two-dimensional Computational Fluid Dynamics (CFD) method, a parametric study was conducted in order to determine which of the three configurations meet with the requirements imposed by the Moroccan thermal building regulation. In terms of thermal resistance R and thermal transmission coefficient U, results have shown that double brick walls with 12 and 16 hemp concrete filled holes were the only configurations meeting the requirements of Moroccan Thermal Regulation. Afterwards, the study was revolved at a whole building scale and a dynamic thermal simulation considering various internal parameters was performed using TRNSYS software. Furthermore, an economic and environmental analysis was conducted and a comparison with Moroccan thermal regulation shows that our results perfectly meet the requirements of this regulation and are more efficient from thermal, economic and environmental perspectives. Finally, the insulation technique used in this investigation can be widely applied around the World and similar thermal performances can be achieved for the case of different regions characterized by the same Mediterranean warm climate considered in this paper.

In-plane flexural behavior of hollow brick masonry walls with horizontal holes

Recent seismic events proved that buildings built with hollow brick masonry walls performed quite poorly when subjected to horizontal actions. To provide insights, an experimental study was conducted to evaluate the flexural behavior of existing slender masonry walls built with clay hollow bricks with horizontal holes and cement-based mortar. Two full-scale specimens were designed and built to exhibit an in-plane rocking behavior when subjected to cyclic horizontal loads such as those induced by an earthquake; the pivotal aim of the experimental test is to assess the actual ductility of such a mechanism for this specific wall typology. The test results show that, unlike other masonry wall typologies exhibiting ductility in the case of in-plane flexural mechanism, this construction typology performs quite poorly under horizontal loads also in the case of rocking, with very little deformation capacity, which reduces by increasing the compressive strength of the mortar. A sudden failure was observed for quite reduced drifts in the experimental tests; failure was associated with the brittle crushing of the pier toe, in which compressive stresses were concentrated. The brittle collapse mechanism also entails the inability of the wall to further sustain the vertical loads, once the ultimate in-plane flexural capacity is reached. A numerical study was carried out; the finite element model was validated against the experimental results. The comparative assessment showed that the finite element model accurately predicts the structural behavior, lateral strength, and failure mechanism of the specimens. Parametric analyses on the validated finite element model (FEM) were carried out to further investigate the structural behavior of different wall layouts or mechanical properties. Finally, a simplified bilinear behavior-curve is proposed to model the flexural response of slender walls, which can be specifically implemented when addressing an equivalent frame approach in the seismic vulnerability assessment of existing buildings built with the analyzed construction typology.

Impact of insulation materials and wall types of reference buildings on building energy efficiency with three methods in Çorum city

AbstractThe improvement of energy efficiency in buildings is one of the most important factors of the energy policy of Turkey owing to its energy import, especially of natural gas. Çorum city, one of the colder cities of Turkey that uses a high amount of natural gas as fuel for heating, was selected to demonstrate the reduction in energy loss and carbon dioxide emissions of buildings and to contribute to the insulation sector in the Çorum industry. Therefore, two different methods, namely, the Turkish standard 825 and heating degree‐days, are applied in cost‐optimal methodology, using four types of traditional insulation materials, namely, standard expanded polystyrene, neopor (graphite‐added expanded polystyrene), extruded polystyrene, and stone wool, and two state‐of‐the‐art insulation materials, aerogel and vacuum insulation panels in two types of reference buildings comprising hollow brick and pumice stone walls. As a consequence of application of the Turkish standard 825 and heating degree‐days methods in the cost optimal methodology of the European Energy Performance of Buildings Directive with the utilization of the optimum insulation thicknesses of six types of insulation materials calculated from both the Turkish standard 825 and heating degree‐days methods at four different types of windows and one top side measure, a new methodology was developed. Results obtained from three methodologies are compared based on insulation materials and wall types.

Dynamic thermal performance of multilayer hollow clay walls filled with insulation materials: Toward energy saving in hot climates

This study examines the benefits of incorporating passive techniques into multilayer hollow clay brick walls to improve their dynamic thermal performance. The finite element approach was used to solve the incompressible Navier-Stokes and energy equations to analyze the dynamic thermal response of walls exposed to real thermal excitations of the Marrakesh climate. The results show that increasing the emissivity from 0.1 to 0.9 significantly increases the total heat load over 24 h. Furthermore, filling 100% of the cavities with insulation materials delayed the temperature peak by about 2.3 h and lowered the decrement factor by roughly 43%, with a value smaller than 0.07. In addition, it is demonstrated that the total thermal load is reduced by approximately 28% for improved wall configurations (100% insulation filling cavities) compared to traditional wall configurations (100% air filling cavities), which aids in improving building energy efficiency.

Seismic behavior of reinforced concrete buildings using chained masonry walls randomly located

The widespread use of masonry infill walls in the most prone zones to earthquakes, for the execution of multistoried reinforced concrete buildings, as well as the recorded damage caused by earthquakes, have forced us to study their influence on the seismic behavior of these buildings. The distribution of masonry infill walls in these buildings is mainly related to their architectural requirements. The purpose of this article is to assess the influence of the various locations of chained masonry walls, which represent a particular type of masonry infill walls without gaps, on multistoried reinforced concrete buildings. This variation has been studied using the SAP finite element software, by the pushover method, analyzing several two-dimensional multistoried reinforced concrete frames infilled by double-leaf hollow brick walls. The proposed frames have been analyzed by varying the position of the chained masonry walls, based on the seismic criteria of the period, elastic base shear, elastic lateral displacement, ultimate base shear, and initial stiffness. The results were compared according to the above criteria. After comparing the results, it is very clear that the position of the masonry walls has a great influence on the seismic response of the reinforced concrete frames. Therefore, it is very important to take into account the position of the infill in the design phase.

Thermal performance enhancement of hollow brick by agricultural wastes

Because agricultural wastes can be used as good building insulation materials due to their huge output, wide distribution, recyclability, and high thermal resistance, they are the better selections to improve the thermal performance of envelopes in rural buildings. The hollow bricks filled-with agricultural wastes were proposed, and six groups of walls were built by hollow bricks filled with different kinds of agricultural wastes, including reed leaves, reed stems, rice shells, rice straws, and wheat stems in order to select the reasonable agricultural wastes. The simple hot-box heat flow meter method was used to measure and calculate the overall heat transfer coefficient of hollow brick walls filled with agricultural wastes. The experimental results showed that the insulation performance of the hollow brick was significantly improved due to filling agricultural wastes. Five agricultural wastes can reduce the overall heat transfer coefficient of hollow-brick walls by 12.7~32.7%. And the rice straws were the best selection to be filled into hollow bricks and they can reduce the overall heat transfer coefficient from 1.59 W/(K·m2) to 1.07 W/(K·m2), which showed that thermal performance of hollow-brick wall was improved by 32.7%. Hollow bricks filled with agricultural wastes can be utilized for future construction renovation in rural areas as insulation materials.

An investigative study for the prediction of compressive strength of cement-clay interlocking (CCI) hollow brick masonry walls

Masonry structures are used in many parts of the world because of their varying benefits of being low-cost, heat insulations, local availability, and skilled labor. Therefore, to investigate the compressive stress-strain behavior and detailed analysis and assessment of masonry structures made of CCI bricks is imperative. Axial compressive results of 10 hollow cement-clay interlocking (CCI) bricks made masonry walls are presented. 10 masonry walls were tested under concentric compressive load in 2 groups. Bricks of each group had different compressive strength. Five walls in each group comprised of 1 control wall (ungrouted), 1 wall grouted with Ordinary Portland Cement (OPC), 1 wall grouted with non-shrink (NS) cement, 1 wall grouted with OPC and strengthened by steel bars, and 1 wall grouted with NS and strengthened with steel bars. Among 5 walls in each group, control wall created the lower bound in terms of the peak load sustained. While the upper bound was created by the wall grouted with NS cement and further strengthened by steel bars. It was found that the addition of grout (irrespective of its type) significantly improved the peak compressive load. However, increase in peak load over that of the control wall was associated to the grout type. Walls grouted with NS cement attained higher peak loads as compared to those grouted with OPC. It was observed that the addition of cement grout does not guarantee a ductile post-peak behavior. Addition of steel bars not only increased the peak loads, but it also improved the post peak behavior. Accuracy of existing compressive load analytical models was assessed, and it was found that none of the analytical models considered were able to predict close approximations. A linearly regressed model is proposed to predict compressive strength of CCI brick masonry walls with good accuracy.

Thermal and mechanical characterization of adobes bio-sourced with Pennisetum setaceum fibers and an application for modern buildings

The purpose of this paper is twofold: to propose a sustainable eco-construction practice using highly biosourced earth blocks in contemporary buildings, taking into account their poor mechanical properties; and to assess the effect of incorporating Pennisetum Setaceum (PS) fibers on the thermomechanical performance of adobes, where earth was biosourced with PS fibers at weight percentages of 0, 2, 4, 6, and 8%. Firstly, raw materials’ geotechnical, mineralogical, chemical and microstructural characteristics were identified. Afterward, the thermal and mechanical properties of produced PS-adobes were studied by hot disk method, uniaxial compressive and tensile splitting strength tests. The impact of fiber content on the durability of adobes was also discussed using capillary water absorption test. Experiments reveal that the strength performance of adobes decreases with increasing fiber content while the cohesiveness of mixtures improves. The cohesion improvement was confirmed via the water absorption test. Adding 8%wt of PS fibers can improve the thermal insulation and the heat capacity of adobe by 56.7% and 17.9%, respectively. Laboratory testing was followed by CFD analysis to underline the efficacy of a hybrid bio-based wall in which a PS-adobe layer is incorporated into a double hollow brick wall. The numerical results show that a 10-h time lag was achieved with biosourced earth layer thickness of 90 mm. As a result, high bio-content adobes may be employed as a green thermal mass element in modern buildings with a contribution to thermal insulation.

Optimal insulation thickness of walls using improved Particle swarm optimization

Uninsulated external walls and inappropriate insulation of buildings are the main reason for energy losses. In this study, novel configurations of multi-layer pre-fabricate wall elements were used to enhance the ability of energy-saving and decrease the payback periods and investments in residential houses in five cities in Iran with different energy demands. Also, an optimization strategy is applied to determine optimum insulation thickness for external walls. The evaluation process is based on using natural gas and electricity in Iran’s buildings for heating and cooling, respectively. The optimum required insulation thickness in Cities with different climates according to their degree/day value for four different insulation materials (extruded polystyrene, glass wool, rock wool, and polyurethane) is achieved using a novel optimization method (Improved PSO). According to the obtained results, annual cost saving for of the wall in case of simultaneous heating & cooling is more than cooling and heating alone. However, for the payback period, simultaneous heating & cooling has a lower payback period than cooling and heating alone. The results revealed that the cost of rock wool is higher, and the cost of polyurethane is higher than the cost of all other insulating materials in Ardabil. Also, the optimal insulation thickness for the Ardabil city with hollow brick walls and heating and cooling needs is and for the XPS, respectively.

A structural wall incorporating biosourced earth for summer thermal comfort improvement: Hygrothermal characterization and building simulation using calibrated PMV-PPD model

The drive to design modern low-environmental impact buildings with high-energy efficiency has led to an increase in unfired earth masonry studies reflecting the rising trend of earth used in passive buildings. This paper deals with the efficacy of incorporating biosourced earth in the building envelope. Firstly, the development and the hygro-thermo-mechanical characterization of earth blocks biosourced with local agro-aggregates (Alfa fibers and sawdust) were conducted. An aggregate-to-earth replacement ratio of 8 wt% was adopted. Mechanical tests show that earth blocks alone have a compressive strength of about 1.7 MPa. The hygrothermal tests reveal that biosourced blocks exhibit excellent hygrothermal properties, especially specimens with short Alfa fibers. A twofold decrease in the thermal conductivity value and a significant increase of the time lag and sorption capacities were achieved. The moisture buffering tests show that Alfa fibers improve the buffering capacity of earth from 1.9 to 2.3 g/(m2.%RH), leading the blocks to be classified as “Excellent” humidity regulators. Following the laboratory tests, and to overcome the low mechanical strength of earth, a double hollow brick wall integrating biosourced earth was studied. Building-scale benefits during summer were identified using a validated PMV-PPD model, implemented in EnergyPlus, based on real-time monitoring of an existing building. The findings show that the proposed wall increases thermal comfort by regulating indoor temperature and humidity, reducing 24.6% in dissatisfied occupants compared to typical walls. It is concluded that the use of earth presents a sustainable practice for constructing eco-efficient buildings with enhanced occupant satisfaction in hot regions.

Exploring the thermal behaviour of building materials: Terracotta, concrete hollow block and hollow brick, under the arid climate, case study of Biskra-Algeria

Over time, the need for acceptable indoor thermal environment is inevitable, this need become more alluded in spaces that staying indoor is remarkably more than others (e.g. residential buildings). Also, saving natural resources through adapting the appropriate materials in buildings’ envelopes is an important up-to-date issue. The purpose of this paper is to explore the thermal behaviour of different houses’ envelopes of several materials (terracotta, hollow concrete block and hollow brick walls). In order to understand their performance, three different cases study in Biskra (South of Algeria) have been analysed through in-situ measurements of: outdoor air temperature, external and internal wall radiant temperature. The results show that the terracotta wall has a good thermal behaviour compared to the other walls in term of providing constant and reduced values between external and internal surfaces. This study can be useful for further investigations of classifying materials according to their thermal behaviour and encouraging the use of local materials in hot-dry regions.

Analysis of the thermal behavior of hollow bricks walls filled with PCM: Effect of PCM location

The drastic heat waves intensified by climate change have urged the cooling demand in the building sector. Therefore, thermal comfort in buildings has become a significant energy consumption issue. The building envelope is the primary separator between the conditioned indoor and the unconditioned outdoor environments of the building. This physical separator controls energy exchange and balances the storage capacity of the building. Thermal energy storage can be enhanced using Phase change materials (PCMs). Hence, using these materials can improve the thermal mass of building envelopes. This paper investigated the energy performance of the hollow brick wall filled with phase change materials. It inspected PCM’s behavior by analyzing the impact of PCM placement in a double wall of hollow bricks. In this regard, four PCM positions in hollow bricks were numerically studied in a warm climate city. The results demonstrated the possibility of filling blocks with PCM in selected locations instead of filling the entire brick. Regarding energy savings, the phase change material in locations 3 and 4 saves up to 97% of the energy required to maintain internal thermal comfort at a set temperature of 26 °C.

Acoustic and Thermal Correlation for a Building’s Envelope in a Mediterranean Climate in Morocco

The aim of this paper is to present a comparative analysis of the thermal and acoustic insulations of four different buildings' envelopes: Single layer clay brick wall (Wall(a)), Single layer concrete brick wall (Wall(b)), double layer hollow brick wall with a medium of polystyrene (Wall(c)) and double layer hollow brick wall with a medium of air (Wall(d)), which are all modelled and simulated by using finite element method (FEM) under different climatic conditions. Moreover, the study of noise transmission through these walls was released by placing a linear nonmonochromatic source of sound 1m away from the exterior side of each wall and it is emitted sound waves with a velocity of 200 m/s with low frequencies, while an acoustical comparative analysis was investigated under the same thermal conditions as the two previous steady states study. The analysis of the heat transfer and sound pressure level (SPL) variations through the walls (a), (b), (c) and (d) shows that the wall (d) is a good thermal and sound insulator compared to the walls (a), (b) and (c) due to the insulation by air gap with a thickness of 0.06 m, it provides a high rate of sound pressure level attenuation compared to the other walls under study. Finally, the insulation by air-gap gives is good enough to ensure simultaneously energy savings and acoustic comfort.

BENEFIT FROM CHAINED MASONRY WALLS TO IMPROVE THE SEISMIC RESPONSE OF REINFORCED CONCRETE BUILDINGS

The multiple earthquakes have proved the effect of chained masonry walls on the seismic behavior of multistoried reinforced concrete buildings. The chained masonry walls have been considered one of the types of masonry infill walls but without gaps. This participation came intending to study this effect through the modeling of several two-dimensional frames for a multistoried reinforced concrete building, taking into account the hollow brick walls, which represent the most common type in Algeria. We analyzed the proposed models using ETABS finite element software, relying on the response spectrum method and respecting the most important requirements according to the applicable Algerian Seismic Code. After analysis of the different models, the results have been compared according to the parameters of the period, base shear, lateral displacement, and stiffness. Through a critical synthesis of the results, we concluded that these walls could significantly affect the seismic behavior of this type of buildings. Moreover, the neglect of these walls in the modeling process can lead designers to have a false perception of the behavior of these buildings towards seismic loadings.