Enhancement of Straw Bale Performance Using Gum Arabic

Background: The negative impacts of the construction industry are compelling arguments for embracing technology that contributes to carbon footprint reduction and resources conservation. Toward the achievement of objective 9 of the Sustainable Development Goals, the development of new building’s materials like straw bale has advanced in the construction industry. As demonstrated in the literature, straw bale is an eco-friendly material that presents many advantages, like its contribution towards a circular economy. However, it has low compressive strength and displays high displacement under compression load. So far, no attempt has been made in order to enhance the strength of straw bales. Objective: This study aimed to develop alternative material to straw bale using chopped straw stems mixed with a binder (gum Arabic) and determine its stress-strain characteristic. Methods: The manufacturing process of the new material involved the use of chopped straw and gum Arabic to form straw blocks. Results: Results obtained show that the compressive strength of straw block (1.25MPa) is greater than the strength of straw bale (0.02MPa). Also, the average displacement recorded during compression load on straw blocks (29mm) was 2.8 times smaller than the displacement in straw bale (80mm). In terms of shape and size, straw blocks match with conventional materials like cement or compressed block. This will facilitate their use in construction compared to straw bales that require skilled laborers for pre-compression and plastering. Conclusion: The use of gum arabic helps in holding straw stems together and forms a compact material with improved strength compared to straw bale. Performance improvement of the characteristics of load-bearing straw bale walls can be addressed by using straw blocks.

Experimental Investigation of Two Test Setups on Straw Bales Used as Load-Bearing Elements of Buildings

The importance of green and sustainable materials in civil engineering is undeniable. Alongside modern practices that improve the properties of standard building materials, there are ways to revive forgotten techniques, including straw bale buildings. Straw bales are load-bearing structures, which are applied based on handed-down experience and lack standard approaches in testing, design, and application. Therefore, a goal ahead is to describe every aspect of the process in technical detail. The objective of this paper is to highlight practical ideas for testing straw bales on a hydraulic press machine and to provide a basic statistical investigation of the results obtained. Two basic series were prepared, one without a side barrier and the other with a side barrier. The reason for this was to delineate the limits of the real behaviour of the straw bale on the load bearing wall of the house. Due to the assumed slight embedment of adjacent bales, the real result were within these limits. The experimental plan, basic results, simplified correlations, and statistical evaluation are presented. Recommendations for a further testing and evaluation are provided. As expected, the results with and without the lateral barrier differ by almost 18% for the true strain.

Earth and Straw Bale: An Investigation of Their Performance and Potential as Building Materials in New Zealand

<p>Is there a future for ‘natural’ or ‘alternative’ building systems in New Zealand? Do they have a role to play in the quest for more sustainable housing solutions? These are the questions that underpin this thesis which looks at the state of earth and straw bale building in New Zealand at the end of the first decade of the twenty-first century, using the Nelson area as a case study. A database of all the earth and straw bale houses in the region has been compiled, followed by a written survey in the form of a questionnaire of 82% of the owners of these houses. Interviews with eleven experts and house owners provided additional information. This information, and that gleaned from a review of research carried out both in New Zealand and overseas has been collated and analysed to present an overview of the current situation. The way in which both earth and straw bale construction have changed over time is documented and the issues currently being faced for both systems are identified. The thesis concludes that there is a future for these natural building systems in New Zealand and identifies areas for further research that would help facilitate this.</p>

Earth and Straw Bale: An Investigation of Their Performance and Potential as Building Materials in New Zealand

<p>Is there a future for ‘natural’ or ‘alternative’ building systems in New Zealand? Do they have a role to play in the quest for more sustainable housing solutions? These are the questions that underpin this thesis which looks at the state of earth and straw bale building in New Zealand at the end of the first decade of the twenty-first century, using the Nelson area as a case study. A database of all the earth and straw bale houses in the region has been compiled, followed by a written survey in the form of a questionnaire of 82% of the owners of these houses. Interviews with eleven experts and house owners provided additional information. This information, and that gleaned from a review of research carried out both in New Zealand and overseas has been collated and analysed to present an overview of the current situation. The way in which both earth and straw bale construction have changed over time is documented and the issues currently being faced for both systems are identified. The thesis concludes that there is a future for these natural building systems in New Zealand and identifies areas for further research that would help facilitate this.</p>

A System for Optimizing the Process of Straw Bale Retrieval

During a baling operation, the operator of the baler should decide when and where to drop the bales in the field to facilitate later retrieval of the bales for transport out of the field. Manually determining the time and place to drop a bale creates extra workload on the operator and may not result in the optimum drop location for the subsequent front loader and transport unit. Therefore, there is a need for a tool that can support operators during this decision process. The key objective of this study is to find the optimal traversal sequence of fieldwork tracks to be followed by the baler and bale retriever to minimize the non-working driving distance in the field. Two optimization processes are considered for this problem. Firstly, finding the optimal sequence of fieldwork tracks considering the constraints of the problem such as the capacity of the baler and the straw yield map of the field. Secondly, finding the optimal location and number of bales to drop in the field. A simulation model is developed to calculate all the non-productive traversal distances by baler and bale retrieval in the field. In a case study, the collected positional and temporal data from the baling process related to a sample field were considered. The output of the simulation model was compared with the conventional method applied by the operators. The results show that application of the proposed method can increase efficiency by 12.9% in comparison with the conventional method with edited data where the random movements (due to re-baling, turns in the middle of the swath, reversing, etc.) were removed from the data set.

Laboratory Investigations into the Bearing Capacity of Straw Bales for Low-Rise Building Applications

Investigations were carried out to study the mechanical performance under uniaxial load of unplastered and plastered straw bales. Results from tests on 30 rice straw bales indicated nonlinear load-bearing properties with large deformations and anisotropy. Since the deformations observed did not conform to the current building code requirements, the evaluation of ultimate bearing capacity through the maximum axial vertical load was not possible. To obtain the design strength of rice straw bales in composite walls, further 21 specimens of plastered straw bales were also tested in compression. The permissible deformation of the straw bales was evaluated. It is noteworthy that the large deformability of straw bales can reduce the damage to structures after an earthquake. Consequently, the straw bale use can widely enhance the seismic performance of low-rise buildings.

Life Cycle Impact Assessment of Load-Bearing Straw Bale Residential Building

As a renewable raw material, straw bale represents a sustainable way of construction with minimal environmental impact. This paper focused on life cycle impact assessment of load-bearing straw bale residential building. Product stage from raw materials extraction to manufacture of construction materials was considered in the assessment including seven variations of straw bale. Construction materials were evaluated due to IMPACT 2002+ method. Both midpoint and endpoint impact categories were included. The results showed the importance of straw bale origin. Ecosystem quality impact of straw from extensively cultivated pastures was twenty times higher than that of intensive crop production, thus making a significant difference to an overall score of the construction. Results showed advantage of straw as a construction material particularly when used locally. In addition, significant contributions of other construction materials were identified.