Earth Bricks Research Articles

Earth as Building Material – an overview of RILEM activities and recent Innovations in Geotechnics

This paper presents an overview of the different earth building techniques, the latest innovations and the normative aspects. The oldest man made earth constructions known to exist date back to 10 000 BC. Since then, earth has remained a popular building material throughout history. With time, different techniques evolved, starting from sundried adobe blocks to cob constructions, rammed earth walls and compressed earth bricks. Today these techniques are still being optimized and alternative binders, specifically adapted admixtures and surface treatments are being developed. Even though nearly one third of the world’s population lives in an earth construction, few specific building standards and testing methods exist. Many of the tests used today are based on tests for concrete and thus do not take into account the complex nature of earth constructions, such as their sensitivity to water. RILEM, the union of Laboratories and Experts in Construction Materials, Systems and Structures, set up a new Technical Committee in 2016: TC TCE (Testing and Characterisation of Earth-based building materials and elements). This committee, consisting of an international group of experts on the topic, aim to define testing procedures for earth as a building construction material. To end with, this paper also gives a short introduction to “Deep soil mixing”, an “earth” building technique dedicated to geotechnical engineering.

Construction Considerations for Low-Cost Earth Brick Shells

Construction Considerations for Low-Cost Earth Brick Shells

Earth as Building Material – an overview of RILEM activities and recent Innovations in Geotechnics

This paper presents an overview of the different earth building techniques, the latest innovations and the normative aspects. The oldest man made earth constructions known to exist date back to 10 000 BC. Since then, earth has remained a popular building material throughout history. With time, different techniques evolved, starting from sundried adobe blocks to cob constructions, rammed earth walls and compressed earth bricks. Today these techniques are still being optimized and alternative binders, specifically adapted admixtures and surface treatments are being developed. Even though nearly one third of the world’s population lives in an earth construction, few specific building standards and testing methods exist. Many of the tests used today are based on tests for concrete and thus do not take into account the complex nature of earth constructions, such as their sensitivity to water. RILEM, the union of Laboratories and Experts in Construction Materials, Systems and Structures, set up a new Technical Committee in 2016: TC TCE (Testing and Characterisation of Earth-based building materials and elements). This committee, consisting of an international group of experts on the topic, aim to define testing procedures for earth as a building construction material. To end with, this paper also gives a short introduction to “Deep soil mixing”, an “earth” building technique dedicated to geotechnical engineering.

Behaviour and strength assessment of masonry prisms

This is a case study presenting the cracking behavior and assessment of the compressive strength of masonry prisms. The compressive strength of masonry was determined by performing laboratory tests on 192 masonry prism specimens corresponding to 3 specimens each in 64 groups. The variables considered in the experimental program are type of brick, strength of masonry and height-to-thickness (h/t) ratio of the prism specimen. Pressed earth bricks and burnt clay bricks were used for the preparation of masonry prisms. A mathematical model is also proposed for the estimation of compressive strength of masonry prisms by performing a statistical multiple regression analysis on 232 data sets, which includes 64 test data from the present study and 168 test data published in the literature. The model was developed based on the regression analysis of test data of prisms made of a variety of masonry units namely clay bricks, pressed earth bricks, concrete blocks, calcium silicate bricks, stone blocks, perforated bricks and soft mud bricks. The proposed model not only accounts for the wide ranges of compressive strengths of masonry unit and mortar, but also accounts for the influence of volume fractions of masonry unit and mortar in addition to the height-to-thickness ratio. The predicted compressive strength of prisms using the proposed model is compared with 14 models available in published literature. The predicted strength was found to be in good agreement with the corresponding experimental data.

The mechanical and physical properties of unfired earth bricks stabilized with gypsum and Elazığ Ferrochrome slag

Abstract During the last few years, an increasing interest has been appeared for earth as a building material. Earth-based materials have been studied because of energy efficiency and ecologically sustainability. The chromite deposits, 10% of the world reserves, are processed in Elazig Ferrochrome Factory in Eastern of Turkey. Elazig Ferrochrome slag (EFS) as a by-product of the factory is produced roughly 50,000 tons in a year. The disposal, removal and storage of this by-product is a serious problem. Therefore, the utilization of this waste material in building applications is very important. The aim of this work is to investigate effects of gypsum and EFS additives on mechanical and physical properties of unfired earth brick (UEB) materials in order to assess their potential advantages in building applications. The earth material was characterized by laboratory tests. Four different UEB samples were produced by using different compositions of earth, gypsum, EFS and straw fibers. Compressive strength, water absorption coefficient, drying shrinkage, ultrasonic pulse velocity (UPV) and density of the prepared UEB samples were determined. The experimental findings have showed that the usage of gypsum and EFS in stabilizing process of UEBs was advantageous.

Mechanical and thermal characterization of stabilized earth bricks

In Senegal, soil is used in construction with a misunderstanding of the thermal and mechanical properties. The lifespan of building considerably depends of the mechanical properties of construction materials used. The thermal properties of construction materials have considerable influence on the energy performance of the building. This work deals with the determination of thermal and mechanical properties of soil bricks stabilized with cement produced by five handicraft manufacturers. For the mechanical characterization, we determine the compressive strength of bricks using a mechanical press. The thermal characterization is to determine thermal capacity and thermal conductivity of bricks by asymmetrical transient Hot Plate method. The results show that vibrated bricks have a compressive strength of about 1.6 MPa and a thermal conductivity of about 0.8 W.m-1.K-1. The compressed bricks have better compression strength of about 2 MPa and a thermal conductivity of about 0.7 W.m-1.K-1.

A Review of Compressed Stabilized Earth Brick as a Sustainable Building Material in Nigeria

A Review of Compressed Stabilized Earth Brick as a Sustainable Building Material in Nigeria

Effect of Plant Aggregates on Mechanical Properties of Earth Bricks

AbstractA building material is mainly characterized by its mechanical performance, which provides proof of its quality. However, the measurement of the compressive or flexural strength of an earth-...

Preventing overheating in offices through thermal inertial properties of compressed earth bricks: A study on a real scale prototype

Buildings are increasingly required to be efficient not just in their operation, but from construction to demolition. Thus, interest in natural construction materials with low embodied environmental impacts has increased, (re)inventing materials and components from vernacular architecture. Compressed Earth Bricks (CEBs) are an example of this kind of component. They are flexible in a wide range of applications and their natural features favour their usage as thermally massive elements to increase a building’s thermal inertia (TI). The ability to store heat during the day and release it later helps buildings in dampening thermal swings, making TI a good strategy for preventing overheating in offices usually characterized by critical internal loads.Previous studies highlighted the difference between the thermal behaviour results obtained with tests on the materials, like experiments in controlled climatic chambers and real-world applications. In this study, an application of CEBs is taken as a case-study to analyse the thermal behaviour of an earthen wall and the potential of coupling night ventilation to stabilize temperatures and increase indoor comfort. Comparing the results obtained in two different rooms, representative of lightweight and heavyweight earthen construction, it was possible to quantify the contribution of CEBs walls to the passive cooling strategy in office buildings, according to different ventilation profiles/scenarios.

Mechanical and hygrothermal properties of compressed stabilized earth bricks (CSEB)

In Africa, compressed stabilized earth bricks are used increasingly in construction. The mechanical, thermal and hygroscopic properties of earth-based building materials available in the African market are not known with accuracy. For this reason, it is often difficult to predict the thermal behavior and the sustainability of buildings made from earth bricks. The work presented in this paper aims at measuring the mechanical, thermal and hygroscopic properties of compressed stabilized earth bricks (CSEB) produced by eight brickworks in Senegal. These properties include compressive strength, thermal conductivity, thermal capacity, and water vapor permeability. The mechanical characterization showed that the compressive strength of CSEB made by these brickworks is insufficient for CSEB to be used in a load-bearing wall according to the African standard ARS 674. The thermal characterization gives an average thermal conductivity of 0.75Wm−1K−1 and an average specific heat of 1040Jkg−1K−1, with a Variation Coefficient of 8% and 7%, respectively. The hygroscopic characterizations show a low resistance to water vapor of these bricks. These values are close to the few data existing in the literature on CSEB.

Thermal characteristics of Model houses Manufactured by date palm fiber reinforced earth bricks in desert regions of Ouargla Algeria

The big desert of Algeria is characterized by a hot and dry climate in summer, cold and dry in winter. In these reinforced concrete construction parts assuredly there was much disappointment to provide a healthy and comfortable indoor climate in buildings. To improve thermal comfort in a building and save energy, it is necessary to implement special performance materials, providing good thermal insulation. In this study we care to about producing clay bricks with good mechanical and thermal properties to reduce energy consumption and increase thermal comfort in the home. The objective of this research is to prepare clay bricks and examine afterwards with some mechanical and thermal tests. We have made some prototypes tested by these bricks who gave good thermal and mechanical properties in order to try to use them in the field of construction. We made the percentage of sand set at 30% and that of the fiber from 0% to3% by weight. The results of these tests showed that the increase in% of fiber is beneficial to the improvement of the thermal properties with acceptable mechanical strength. At14:00h, a remarkable temperature difference compared to the control performed in industrial prototype brick was obtained.

Hydraulic System Design for Earth Brick Press

An earth brick press is introduced in this paper. Bake-free bricks produced by this machine are low in cost and environmentally friendly. Moreover, they may be substituted for other building materials required in building breeding sheds and greenhouses. In this paper, calculation and selection of design and type are respectively conducted by introducing the structure and operation of key hydraulic parts for the machine.

Performance of Earth Bricks Supplemented by Nanoparticles and their Application in Architecture

The potential for architecture offered by natural materials in terms of comfort, reduction of embodied energy and energy-saving in the operational phase, dictates in-depth research that might highlight advantages and contribute to improving their characteristics. This research focuses on earth bricks and, in particular, a type of brick made from unfired clay, known as adobe. The aim of the research is to verify improvements in performance of adobe with the aid of nanotechnology. The adobe mixture was prepared with water, soil (from Sicily) and LAPONITE® as a stabilizer. The adobe bricks were subjected to tests of resistance to compression and flexion, resistance to abrasion, capillary absorption of water and resistance to impact. The results may be deemed positive, in particular those relating to resistance to compression. Further research will be necessary, especially with regard to problems of water absorption.

A comparative study of compressed earth bricks (ceb’s) and sandcrete blocks for building construction

This study examined the production and testing of sandcrete bricks and compressed earth bricks (CEB’s) with a view to comparing their strength and moisture content of materials used. Some units of sandcrete bricks and laterite bricks were made using machine vibrated sandcrete brick mould and hydraulic brick making machine respectively. The bricks were tested to determine their moisture content and compressive strength. The results obtained from the tests were compared with the specifications of Nigerian Building and Road Research Institute (2006), Nigerian Building Code (2006), and Nigerian Industrial Standards (2000). The results indicated that the compressive strength of 300×150×170 sandcrete bricks varies from 1.3 N/mm2 to 2.6 N/mm2, as the curing age increases from 7 to 28 days. For laterite bricks, the strength varies from 1.0N/mm2 at 7 days to 2.2N/mm2 at 28 days. All the bricks produced satisfied the minimum requirements in terms of compressive strength, by all available codes, but the compressive strength of sandcrete bricks is higher than the CEB’s. It was concluded that sandcrete bricks have better strength compare to compressed earth brick, more so compressed earth bricks (CEB’s) absorb more water than sandcrete bricks, and sandcrete bricks can be use as substructure (foundation unit). It was recommended among others that sandcrete bricks should be used for foundation of a building.Keywords: Concrete, Sandcrete bricks, Laterite, Compressed Earth Bricks (CEBs), Building, Compressive strength

Thermal Conductivity of Compressed Earth Bricks Strengthening by Shea Butter Wastes with Cement

Currently, in a context of sustainable development, the economic and environmental challenges incite, to valorize local materials such as clays and agro-industrial waste. It is in this approach that a new category of compressed earth bricks (BTC) stabilized with shea meal (TK) and cement was proposed. The purpose of this paper is to investigate the effect of shea meal rate on the thermal conductivity properties of cement stabilized earth bricks. A lateritic clay (Lat) mainly composed of kaolinite (38.44%), quartz (24.94%), goethite (12.28%), hematite (4.44%) and illite (19.9%) was used to make bricks. Different mix designs made up of lateritic clay and 5% cement were studied. The shea meal is added as a partial lateritic clay replacement in different proportions. The thermal conductivity was determined by hot disk method and correlated to both porosity and density of elaborated materials. The results obtained show that the thermal conductivity and density of bricks decrease respectively from 0.72 W·m-1·K-1 to 0.52 W·m-1·K-1 and from 2.77 g·cm-3 to 2.52 g·cm-3. The presence of shea meal within the material generates pore formation, which may partly explain the improvement of the thermal insulation properties. A positive correlation was noted between density and thermal conductivity of these materials.

Strength and Absorption Rate of Compressed Stabilized Earth Bricks (CSEBs) Due to Different Mixture Ratios and Degree of Compaction

Compressed Stabilized Earth Brick (CSEB) is produced by compressing a mixture of water with three main materials such as Ordinary Portland Cement (OPC), soil, and sand. It becomes popularfor its good strength, better insulation properties, and a sustainable product due to its easy production with low carbon emission and less skilled labour required. Different types of local soils usedwill produce CSEB of different physical properties in terms of its strength, durability, and water absorption rate. This study focuses on laterite soil taken from the surrounding local area in Parit Raja, Johor, and CSEB samples are produced based on prototype brick size 100×50×30 mm. The investigations are based on four different degree of compactions (i.e. 1500, 2000, 2500, and 3000 Psi) and three different mix proportion ratios of cement:sand:laterite soil (i.e. 1:1:9, 1:2:8, 1:3:7). A total of 144 CSEB samples have been tested at 7 and 28 days curing periods to determine the compressive strength (BS 3921:1985) and water absorption rate (MS 76:1972). It was found that maximum compressive strength of CSEB was 14.68 N/mm2 for mixture ratio of 1:3:7 at 2500 Psi compaction. Whereas, the minimum strengthis 6.87 N/mm2 for 1:1:9mixture ratio at 1500 Psi. Meanwhile, the lowest water absorption was 12.35% for mixture ratio of 1:2:8 at 3000 Psi; while the 1:1:9 mixture ratio at 1500 Psi gave the highest rate of 16.81%. This study affirms that the sand content in the mixture and the degree of compaction would affect the value of compressive strength and water absorption of CSEB.

Comparison of Strength Between Laterite Soil and Clay Compressed Stabilized Earth Bricks (CSEBs)

Compressed Stabilized Earth Brick (CSEB) is a sustainable material utilizing locally available soils mixed with stabilizers to increase its strength. Two main factors affecting the strength of prototype are its compressive strength and water absorption rate. In this study, the mix proportion ratio for producing CSEB prototypes from laterite soil and clay types was 1:10 (cement:soil). Three different compactions (i.e. 2000, 3000, and 4000 Psi) were applied to produce prototypes with dimension of 100×50×40 mm. The samples were tested at the ages of 7 and 28 days. For laterite soil CSEB, the optimum strength was achieved by the sample subjected to 2000 Psi compaction,withits compressive strength of 9.0 N/mm2 and water absorption rate of 14.9%. For clay CSEBthe optimum strength observed was the sample subjected to 4000 Psicompaction, with the compressive strength of 5.8 N/mm2 and water absorption rate of 17%. However, the compressive strength of clay CSEB is still below the level specified in the MS 76:1972, which is over 7 N/mm2 for the load-bearing fired brick Class (1). This study also revealed that the increased in compression pressure would result in different strength performances for both CSEBs made from laterite soil and clay.

Effectiveness of Cement and Lime in Earth Bricks for Building Construction

Effectiveness of Cement and Lime in Earth Bricks for Building Construction

Modification of Yellow River Sediment Based Stabilized Earth Bricks

Modification of Yellow River Sediment Based Stabilized Earth Bricks

Geotechnical characterisation of lateritic soils from south-western Nigeria as materials for cost-effective and energy-efficient building bricks

Lateritic soils which have been described as highly weathered tropical or subtropical residual soils were studied with an attempt to establish its suitability or otherwise as sustainable material in building bricks and housing development that will meet the present challenge of sustaining the environment without costing too much and maintaining a high standard of strength, durability and aesthetics. Index properties of the tested lateritic soils revealed them as mostly well graded, comprising both cohesive (silt and clay) and cohesionless (sand and gravel) soil fraction. The geotechnical analyses on the studied lateritic soil revealed a strong compressive strength with a relatively sound dry density which could guarantee a good durability in resulting bricks made from these soil materials. Further test on the strength and durability of the compressed earth bricks (CEBs) made from these lateritic soils revealed a brick with compressive strength ranging between 6.33 and 15.57 MPa which is considered to be of good strength coupled with its sound durability strength established over a period of more than one year under a complete cycle of weather and seasonal conditions. In conclusion, lateritic soils from the study area were found to be suitable as materials for bricks (CEB) with good compressive and durability strength which qualifies them as sustainable and cost-effective materials for low-cost housing development.