Clay Blocks Research Articles

Optimising the material emissions of single-dwelling residential buildings using the dynamic life cycle iteration protocols

While developed countries progress in environmental impact mitigation, developing economies struggle to lessen the severity of environmental impact and improve performance strategies. As of 2021, only 199 research publications were linked to African Life Cycle Assessment investigations highlighting the environmental consequences and lack of research in developing countries. In 2022 Ghana's global environmental performance was ranked 170th out of 180 countries, with a score of 27.70 out of 100, showing a ten-year trend of -6.1. This study aimed to optimise single-dwelling residential buildings' material emissions from cradle to gate using first principles through the dynamic life cycle iteration protocols. The following objectives were set: 1) to identify the primary materials in a typical Ghanaian single-family dwelling and apply first principles to model the environmental impact, and 2) to replace the materials with an environmentally friendly type through iteration optimisation. The Building Information Modelling in Revit 2021 was used to design and take off quantities of the materials. The optimisation was conducted through iterations using MS Excel. The baseline model showed that steel and aluminium products generated frontal results of 28.64 ton CO2eq/m2 and 1.96 ton CO2eq/m2, representing 92% and 6% of the total GWP100, respectively. A decrease of 39% in GWP100 emissions was made possible by employing concrete blocks instead of expandable lightweight concrete clay blocks. It is noteworthy that gypsum plasterboard had the lowest material impact across the GWP100, emitting 1895.40 kgCO2eq/m2, or 0.81 percent carbon, during the production phase. The results of this study can aid the many real estate developers and construction firms in developing nations who want to build residential homes using sustainable materials to lessen the effects of climate change caused by using building materials.

Investigating the effect of bentonite compaction density and environmental conditions on the corrosion of copper materials

AbstractThe proposed long‐term management plan for used nuclear fuel is to isolate it within a multiple‐barrier system underground in a deep geological repository (DGR). In the Canadian design, used fuel bundles will be sealed in copper‐coated carbon steel used fuel containers, encased in blocks of bentonite clay, emplaced approximately 500–800 m below ground, and surrounded by a bentonite gapfill material. A laboratory experimental campaign has been undertaken to demonstrate the integrity of the multiple‐barrier system. DGR‐relevant copper materials were embedded in bentonite clay, compacted to various densities, and sealed into a hermetic pressure vessel pressurized with demineralized water. Experiments explored the influence of bentonite compaction in the range of 1100–1600 kg/m3 on copper corrosion over durations of 1–18 months. Postexposure analysis of the copper coupons showed nonhomogeneous corrosion, with corrosion products composed of Cu2O, with some Cu2S. The average corrosion rates decreased as a function of time and increasing bentonite compaction density. In general, we observed that higher bentonite compaction density suppressed the corrosion of embedded copper.

Theoretical Evaluation for Soil Thrust of Single-Track System over Clay Slope via Upper Bound Analysis

This study aimed to theoretically evaluate soil thrust on a clay slope as a reaction force associated with the motion of an off-road tracked vehicle. The existing concept of the potential failure modes of a clay block on flat ground has extended to determine the soil thrust of sloped clay ground. Based on the upper-bound limit analysis, the soil thrust under the most critical failure was derived for three potential failure modes: block, triangular-wedge, and trapezoidal-wedge failures. Specifically, the influence of the slope angle, the shear strength of clay, the weight of a vehicle, and the geometry of a track system on the soil thrust was investigated. Only the block and triangular wedge failure modes were able to occur, and the geometry of a single-track system could lead to different failure modes. Under the block failure mode, the soil thrust decreased as the slope became stiff, and the vehicle weight increased. On the other hand, the soil thrust decreased as the slope angle decreased under the triangular-wedge failure mode.

Influence of using clay block with increassed mass on energy performance of an office builidng in Nis

The objective of the research was to compare various types of clay blocks in terms of construction thermal inertia parameters and the influence they would have on the energy performance of an office building located in Nis. For this, a new type of clay block with increased mass is proposed, and a custom approach for determining all relevant indicators is described, intensively relying on building energy performance simulations. Fourteen configurations of external walls made of clay blocks, including the newly proposed block with increased mass, were investigated using EnergyPlus with a custom weather file to obtain construction thermal storage indicators, i.e., time lag and decrement factor. The results show the average decrement factor of less than 1% and the average time lag of approximately 9 hours for the newly proposed clay block, which is very similar to the values obtained for commercially available clay blocks. In addition, the same model of the building was used to check the influence that this increased mass has on the energy performance of the building served by a low temperature radiant and fan coil system. The results indicate the possibility of reducing heating energy consumption by 3.65% by using the increased mass clay block, while maintaining similar wall U-values, when compared with regularly used clay blocks, with a negligible change in cooling energy consumption.

Predlog upotrebe otpadne staklene ambalaže kao sekundarne sirovine u proizvodnji blokova od gline

The main objective of the present study was to propose the feasible usage of secondary raw material obtained from waste glass containers in the manufacture of clay blocks, driven by environmental benefits. Main goals were to reach a high content of waste glass in clay blocks, to use very low firing temperature and still obtain products with suitable physical and mechanical properties. Blocks with 10 wt. %, 20 wt. %, and 30 wt. % of waste glass in content were experimentally produced with the firing temperature of 880 °C. Relevant physical and mechanical properties were measured and their dependence on waste glass content was determined. Material flow analysis (MFA) showed that utilization of waste glass in clay block production can generate positive environmental impacts including landfill lifespan extension and contribution to the waste glass recycling.

Investigation on the strength of expanded clay aggregate concrete specimens after thermal exposure

The article describes the results of a laboratory study of the properties of expanded clay blocks. Expanded clay concrete modular blocks are used to install chimney stacks. The research aims to determine how the physical-mechanical properties of the material change when they are exposed to high temperatures. The question is raised about how much the strength of the structural material can decrease if it is exposed to higher temperatures. To broader and more objectively determine the material properties, materials with different fillers were chosen for the sample blocks. 24 expanded clay concrete blocks were formed for the study. The samples were hardened under uniform conditions in the laboratory. After the anticipated hardening time, the weight of the samples was determined, and they were weighed again after thermal exposure. Having adjusted the mass of expanded clay samples, their compressive strength properties were investigated. The research was carried out in the KUT Building Materials Laboratory following the requirements for compressive strength established in the normative documents. After comparing the changes in the weight of expanded clay concrete sample blocks before and after thermal effects, the obtained results showed that the weight of the samples with coarse expanded clay filler and fibre decreased significantly after temperature exposure at 105 °C. After exposure of the same samples to temperatures of 300 °C and 600 °C, their mass decreased even more. Before performing the compressive strength test of expanded clay concrete samples, all sample cubes were numbered and divided into three groups after thermal exposure. To compare the research results, control samples were separated from each group of foamed cubes with different fillings. The results of the compressive strength of the control samples were compared with the results of the thermally affected samples. The research revealed that the samples with fine-grained filler retained the highest strength after exposure to high temperatures, while the strength results of all other samples with coarse filler and coarse filler with fibre were low. The comparison of the results of the compressive strength of expanded clay concrete samples with coarse fillers suggests that the samples with fibre remained stronger after exposure to high temperature (600 °C) than the samples without additives. To sum up the results of the laboratory test of expanded clay concrete samples, it can be assumed that their strength may decrease by up to 38 per cent when exposed to expanded clay concrete at high temperatures for a longer period.

Research of the Influence of Various Factors on the Thermal Conductivity of Large-Format Vertically Perforated Clay Blocks

Research of the Influence of Various Factors on the Thermal Conductivity of Large-Format Vertically Perforated Clay Blocks

Analytical prediction of the seismic resistance of masonry buildings retrofitted by Steel Fiber Reinforced Mortar coatings

An extensive experimental program has been performed in the last years at the University of Brescia to show the effectiveness of the in-plane seismic strengthening or repairing of existing masonry buildings by Steel Fiber Reinforced Mortar (SFRM) coatings. In particular, the tests on a full-scale hollow clay block masonry building showed the applicability of the retrofitting technique on the external surface of the structure only.An analytical model already developed and validated is briefly presented in this article and applied to the building experimentally tested. Particular attention is paid to the simplified schematization of the masonry piers based on the fracture lines expected before and after retrofitting. The effectiveness of the analytical model in predicting the seismic resistance of the building is assessed by comparing the analytical results with those obtained from the experimental test.Finally, the analytical model is applied to a real two-story residential building made of concrete hollow units to perform the seismic verification of the structure. The analytical prediction of the global seismic resistance of the building is compared with that obtained from a non-linear static analysis carried out with the finite element program Midas FEA. The results of the comparison will further prove the reliability of the proposed analytical model.

The performance of vertically perforated clay block masonry in fire tests predicted by a finite-element model including an energy-based criterion to identify spalling

Fire tests on masonry are one of the most expensive experiments in developing new vertically perforated clay block geometries. Numerical simulations might be a reasonable substitute for such experiments, leading to a significant cost reduction in the development phase. However, the prediction of such tests with numerical modeling concepts is challenging due to large temperature and stress gradients, highly non-linear material effects, and the complex geometry of the blocks. Herein, we present a finite-element-based concept, including thermal and mechanical simulations, a unit-cell approach, a smeared damage model, and a novel energy-based spalling criterion to describe the structural and material behavior of a masonry wall in a fire experiment. We could predict the obtained spalling times of longitudinal webs and the total endurance of a masonry wall without any empirical fitting parameters in good agreement with experimental data. These results show that we can use our modeling approach for simulating such fire tests, enabling a much cheaper and more efficient development of block geometries.

Validity of Euphrates River Terraces Deposits between Baghdad and Fallujah for Concrete Works

Four sites for deposits between Baghdad and Fallujah were studied. The results showed that all sites conform to the limits of the American Standard Specifications ASTMC33-03 and British Standard Specifications for Building Materials. As for Sieve Analysis for the coarse aggregate, the results for the first and fourth sites correspond to the nominal size of 4.75-19mm, with a deviation at the particle size of 19mm in the second and third sites. The apparent specific weight values ranged between 2.72-2.75 g/cm3 for fine aggregate and between 2.63-2.64 g/cm3 for coarse aggregate. While the rate of absorption was 1.40-1.63% for fine aggregates and 0.60-1.26% for coarse aggregates. The percentage of fine materials ranged between 1.58-4.51% for fine aggregates and 0.79-1.71% for coarse aggregates. The percentage of clay blocks and friable materials was 2.31-12.09% for fine aggregates and 0.39-1.55% for coarse aggregates. The percentage of lightweight materials is between 0.30-0.58% for fine aggregates and 0.24-0.48% for coarse aggregates. The flatness ratio of coarse aggregates ranged between 11.9-13.4% and the elongation ratio between 16.3-20.7%. The percentage of Soundness ranged between 5.56-7.46% for fine aggregates and between 3.14-5.88% for coarse aggregates. The chemical results were within the limits of the standard specifications. One of the most essential recommendations of the current study is to wash the fine and coarse aggregates with water well before use in concrete works should be considered to get rid of impurities, harmful substances, and salts.

Thermophysical Properties of Sawdust and Coconut Coir Dust Incorporated Unfired Clay Blocks

Sawdust and coconut coir dust are agro-wastes/by-products which are suitable for use as raw materials to manufacture unfired clay blocks due to their excellent physical and mechanical properties. A limited number of studies have been conducted on the utilisation of these agro-wastes in clay block production, and they have mostly been devoted to investigating the physicomechanical properties, with less attention given to the thermal properties. Moreover, the majority of the studies have used chemical binders (cement and lime) in combination with agro-waste, thus increasing the carbon footprint and embodied energy of the samples. Furthermore, no research has been performed on the thermal performance of these agro-wastes when incorporated into clay blocks at the wall scale. Therefore, to address these limitations, the present study developed unfired clay blocks incorporating sawdust and coconut coir dust (0, 2.5, 5, and 7.5% by weight), without the use of chemical binders, and evaluated their thermal performance, both at the individual and wall scales. The experiments were divided into two phases. In the first phase, individual sample blocks was tested for basic thermal properties. Based on the results of the first phase, small walls with dimensions of 310 mm × 215 mm × 100 mm were built in the second phase, using the best performing mixture from each waste type, and these were assessed for thermal performance using an adapted hot box method. The thermal performance of the walls was evaluated by measuring the heat transfer rate from hot to cold environments and comparing the results to the reference wall. The results showed that thermal conductivity decreased from 0.36 W/mK for the reference sample, to 0.19 W/mK for the 7.5% coconut coir dust sample, and 0.21 W/mK for the 7.5% sawdust sample, indicating an improvement in thermal insulation. Furthermore, the coconut coir dust and sawdust sample walls showed a thermal resistance improvement of around 48% and 35%, respectively, over the reference sample wall. Consequently, the findings of this study will provide additional essential information that will help in assessing the prospective applications of sawdust and coconut coir dust as the insulating material for manufacturing unfired clay blocks.

Study of clay degradation in an earthslide combining OBIA and roughness analysis of UAV‐based optical images

AbstractFlow‐like landslides in clay slopes pose major threats to people and infrastructure, which has led to numerous studies in recent decades. However, the mechanisms leading to the solid–fluid transition in clay are still poorly understood, despite numerous studies on its rheological evolution. The aim of this study is to contribute to quantify the degradation of clay at the surface of the Harmalière landslide (French Alps) from the analysis of a series of three unmanned aerial vehicle (UAV) acquisitions. Two approaches were combined to process the acquired optical images. First, image classification was performed applying object‐based image analysis (OBIA) to the red, green and blue (RGB) and surface roughness layers. Second, deeper analysis of the surface roughness allows to describe the morphology evolution and to interpret the degradation scheme from undegraded clay to degraded clay.The study shows that the applied methodology is appropriate to perform a thorough analysis of the material degradation pattern on the surface of a landslide. The temporal analysis shows an average degradation rate leading to the complete degradation of a block in about 2 years. Meanwhile, a spatial analysis shows that non‐degraded clays degrade faster in the lower part of the study area, reactivated 30 years ago, than in the upper part, reactivated only a few years ago. In addition, roughness analyses enabled to highlight the evolution of the morphology during the degradation process of the clay blocks, from angular blocks to mounds.

Benefits of wooden structure reuse: the case of an Austrian building

The building sector is responsible for 39% of greenhouse gas (GHG) emissions; thus, it has a significant amount of potential to reduce the effects of climate change. Several active- and passive solutions and strategies have been developed and proposed in the literature. Among them, wood is highlighted as a promising solution to minimize GHG from buildings. However, the benefits, especially in the circular economy, are not fully evaluated due to methodological choices. Motivated by this knowledge gap, this article aims to evaluate the benefits of wood reuse compared to traditional building construction solutions. For this purpose, we have calculated the environmental impacts of a building situated in Graz, Austria. Four different scenarios are considered. The first scenario is a fully reinforced concrete building. The second scenario is a structural beam-column made from reinforced concrete with walls made of concrete blocks. The third scenario is a beam-column made from reinforced concrete with external walls based on clay blocks. Finally, the last scenario is a full wooden building. Following the standardized life cycle assessment (LCA) method, global warming potential (GWP) is calculated through a 0/0 approach. These evaluations were made possible by correlating the impacts released from producing wooden elements and the uptake of biogenic carbon from the forest. Without considering the possibility of material reuse, the wooden structure has a 5 % lower GWP value than the reinforced concrete building. Comparatively, the other building scenarios have almost similar impacts as the building in reinforced concrete. In the case of material reuse, the wooden structure building shows potential to develop projects with 44% lower environmental impacts.

BIM-BASED ENERGY PERFORMANCE EVALUATION OF A BUILDING ENVELOPE IN SEMI-ARID CLIMATE ZONE IN THE MIDDLE EAST

ABSTRACT The BIM building envelope integrates a BIM building’s internal and external environments, improving energy efficiency and substantially lowering energy usage. This research aimed to assess the energy efficiency of typical building envelope materials in Iran. To do this, we used Autodesk RevitR to generate a generic model and DesignBuilderR to conduct an energy analysis. The BIM building envelope integrates a BIM building’s internal and external environments, improving energy efficiency. A BIM building envelope energy analysis was performed on 58 local wall constructions material in Iran. Then, the energy consumption of a BIM building’s HVAC system was then compared against the costs of all external wall alternatives to determine the optimal layer combination. Consequently, the energy simulation results demonstrated that the double external wall structure, 2AAC block core, with XPS (CFC) insulation exterior wall and the single external wall, PERLEX Ultra-Lightweight (PUW) wall performed better. In addition, the clay block wall is found to be the optimum solution for the case study location. The applicability of the proposed system is validated with a case study of a traditional residential building.

Empirical and numerical study on Roma Plastilina #1 ballistic clay under various drop impact tests

The ballistic clay is used to assess protection performance of bulletproof vests. Applying a clay block behind targets conservatively provides similar behavior to the human body as a non-negligible boundary condition. Although understanding and interpreting RP deformation behavior is important, there is no distinctive model covering various impact conditions. We established a numerical model consolidated by a deep neural network which can determine physical input parameters and an empirical formula to understand RP behavior under various impact conditions referring to 59 cases, including our own experiments. The numerical model achieved high levels of accuracy of over 92.6% only when the diameter of the indenter was ø44.5 mm and ø63.5 mm. On the other hand, the empirical model achieved high levels of averaged accuracy of 87.4% for all the cases. The proposed empirical and numerical models can be utilized for assessing protection performance and interpreting impact event of bulletproof vests.

Experimental Qualification of PBO-FRCM Composites for Retrofitting Masonry Structures

This paper discusses the experimental qualification process of Fabric Reinforced Cementitious Matrix (FRCM) composites with Polyparaphenylene BenzobisOxazole (PBO) textiles. FRCMs consist of fiber textiles incorporated within inorganic cement or lime mortar matrices and have emerged as composite materials suitable for the retrofit of unreinforced masonry structures. The Italian Ministry of Infrastructures and Transportation and the European Organization for Technical Assessment have developed guidelines defining standard tests to certify the FRCM mechanical properties for qualification and acceptance purposes. This paper presents part of the experimental qualification results for PBO-FRCM composites with two PBO textiles (unidirectional and bidirectional) applied to two different masonry substrates (clay bricks and tuff blocks), considering tensile, bond and durability behavior. Direct tension tests were carried out on PBO textiles and FRCM specimens, with or without textile lap splices. Single-lap tests allowed determining the bond properties of both FRCMs on clay-brick and tuff-block masonry substrates. The stability of the tensile properties with respect to degradation induced by environmental actions was evaluated by performing direct tensile tests also on FRCM specimens conditioned in humid, saline, and alkaline environments, or subjected to high-temperature stress.

Eggshell and Walnut Shell in Unburnt Clay Blocks

Agricultural residues/by-products have become a popular choice for the manufacturing of building materials due to their cost-effectiveness and environmental friendliness, making them a viable option for achieving sustainability in the construction sector. This study addresses the utilisation of two agro-wastes, i.e., eggshell and walnut shell, in the manufacture of unburnt clay blocks. The experiments were carried out on three series of samples in which first eggshell (10–50%) and walnut shell (5–20%) were incorporated individually and then combined (5% walnut, 10–30% eggshell) in the mixture to assess their influences on the physical and mechanical properties of the unburnt clay blocks. This study performed the following tests: Density, capillary water absorption, linear shrinkage, flexural and compressive strength. The results indicated that eggshell enhanced the strength relative to the control sample when the materials were employed individually, but walnut shell lowered it. Moreover, combining the two materials in the mixer reduced the strength of the samples even further. Nevertheless, the inclusion of the waste materials decreased the density, capillary water absorption coefficient and linear shrinkage of the samples. The findings indicate that eggshell has great potential for unburnt clay block manufacture. However, walnut shell integration needs further research.

Compressive strength of heterogeneous masonry walls containing blends of brick types

The study presents a systematic approach for the evaluation of the compression strength of masonry walls composed of heterogeneous mixes of different types of blocks. First of all, the mechanics of a compressed heterogeneous masonry stack is investigated through a series of experimental tests and Finite Element models, then it is reviewed and discussed. Then, the problem of deriving the necessary material parameters entering the Hilsdorf formula is addressed. Solutions for the correct evaluation of the lacking data are presented based on the existing literature data. Finally, the well-known Hilsdorf formula is extended to the field of block blends with different mechanical properties. A deep experimental investigation on stacks and wallets made with fired clay, limestone and sandstone blocks is introduced for the first time. The comparison of the experimental data with the proposed theory points out the very good predictive capability of the extended Hilsdorf formula derived herein.

Investigation of the adherence between clay blocks and grouts

Abstract This study aims to evaluate the adherence between clay blocks and grouts. For this purpose, push-out and pull-out tests were performed to assess the adherence presented by different combinations of five types of clay blocks and two types of grouts. The results demonstrated that the geometry of the cells of the clay blocks has a preponderant role in their adherence with grout, as the extent of the contact area between grout and block depends on the geometry of the cell. The shrinkage of the grout can cause the formation of cracks at the interface between block and grout, reducing the adherence between the materials. The shrinkage formed inside each type of block can be estimated based on the testing procedure developed in this research and used in conjunction with the geometric characteristics of the cells of the blocks to estimate the maximum load in the push-out tests. The test procedure developed to estimate the percentage of contact area lost due to grouts shrinkage shows to be promising, since its results were used in the equation to estimate the bond strength between blocks and grouts and shown good correlation. However, more study must be done because there are other variables that can affect the results. These results show that it is possible to use different characteristics of blocks and grouts to increase the adherence between these materials and provide a better behavior for reinforced masonry structures. However, it looks like if block types with a grooved hollow cell are used, a bigger contact surface is produced, and a higher bond strength appears to be assured.

Study of the thermal and mechanical properties of local clay materials activated with quicklime, Sefrou (Morocco)

This study aims at testing experimentally the stabilization of unexploited clay from the Bensmim region (Middle Atlas, Morocco) using traditional quick lime from Sefrou located nearly to Bensmim for potential use in building applications. The main purpose of the present work is to evaluate the thermophysical and mechanical behavior of lime-stabilized clay blocks. Many different samples of clay specimens reinforced with lime at six different contents (0%, 10%, 20%, 30%, 40%, 50%, and 70%) were prepared and tested. The thermal characterization was made by the Asymmetrical Hot Plate method in study state and transient regime to identify, respectively, the thermal conductivity and the thermal effusivity. The Flash method was used to evaluate thermal diffusivity. The mechanical performance was measured in terms of compressive and flexural strengths. Besides, a Chemical identification of Bensmim clay was investigated via the X-Ray Fluorescence method. Particle size distribution of used clay was determined following a wet sieving analysis method. The results of clay identification showed that Bensmim clay meets the minimum requirements for manufacturing compressed earth and adobe bricks. The thermophysical tests results showed that the lime addition positively influences the lightness and the thermophysical properties of lime-stabilized clay specimens. For the findings of the mechanical tests, it is observed that the flexural and compressive strengths of lime-stabilized clay blocks continue to increase until a lime content of 30%. After this content, the mechanical performances decrease with lime addition, and no amelioration is detected. Therefore, a lime content of 30% represents the optimal lime content for stabilizing Bensmim clay. At this content, the stabilized clay blocks show optimal mechanical performance and improved thermal properties compared to the reference samples. Stabilized clay blocks at 30% lime content present a 14% improvement in bulk density, 13% in thermal conductivity, 12% in thermal effusivity, 20% in thermal diffusivity, 41% in compressive strength, and 10% in flexural strength, compared to unstabilized specimens.