Life Cycle Assessment of a Wall Made of Prefabricated Hempcrete Blocks

Hempcrete is a natural building material obtained mixing hemp shives (i.e., the woody core of the hemp plant) with a lime-based binder and water. Hempcrete as construction material is gaining increasing interest as the EU aims to achieve net zero emissions by 2050. This material has, in fact, the ability to uptake carbon dioxide from air (i.e., via carbonation) and to store carbon for long time. The goal of the present work is to deeper analyze the environmental profile of hempcrete, in order to assess its potentials in reducing emissions of construction sector. Specifically, Life Cycle Assessment (LCA) of a non-load-bearing wall made of hempcrete blocks is carried on. The analysis encompasses the whole life cycle from the extraction of raw materials to the end of the service life. The analyzed blocks are produced by an Italian company. Only aerial lime is used as binder, microorganisms are added to the blocks to accelerate carbonation. The impact on climate change is assessed through the GWP 100 method proposed by IPCC. Preliminary results reveal a nearly neutral carbon budget.

Overcoming the Perceptual Gap: Worldwide Perceived Comfort Survey of Earthen Building Experts and Homeowners

Earthen building materials are a critical future for sustainable construction because they are locally available, minimally processed, and waste-free. However, despite their advantages, earthen materials still face challenges for comprehensive implementation. First, their technical data vary significantly, making it challenging to quantify their true performance for different climates and environmental contexts. Second, people mistakenly perceive these materials as low-tech and poor in their performance. Lastly, building codes and standards do not comprehensively represent these materials worldwide. This work identifies perceptual barriers that hold back the broader implementation of earthen materials in order to ascertain possible solutions and assess the performance of earthen buildings and perceived comfort among primary resources such as practicing professionals and people who live in earthen houses. The results of an online survey of 126 earthen building experts and homeowners are presented, providing important insights regarding a range of barriers to, and motivating factors for, the implementation of earthen materials, as well as design and thermal performance aspects of existing earthen homes. The results of the surveys show that, of the various earthen building techniques, light straw clay requires the lowest maintenance, and construction of adobe and/or clay plaster encountered the least barriers to implementation. The energy performance of existing earthen homes show that all types of earthen materials reduce the need for cooling, in all climate zones. Insulation over earthen walls was shown to increase occupants’ perceived comfort levels, but only slightly. Additional results provide significant recommendations for future research on thermal performance and comfort guidelines for earthen structures. This study contributes to the development of environmental and policy measures that could be used by policymakers by synthesizing technical and environmental data and by identifying means of improving the perception of natural building.

The Effect of Heat Shocks and Freezing–Thawing Cycles on the Mechanical Properties of Natural Building Stones

The damage to rock masses due to the action of freezing is one of the most important factors in the development of landscapes, the performance of civil structures, and the efficiency of mining operations. In this research paper, the effect has been studied on the physical and mechanical performance of seven different natural building rock samples. The testing program included an experimental study on both dry and saturated intact rock samples and therefore, the effect of saturation on the extent of damage on the tested samples has been discussed as well. Based on the obtained results, freezing–thawing cycles increase the porosity of rock samples and decrease the values of P-wave velocity, uniaxial compressive strength, elastic modulus, and Brazilian tensile strength. Moreover, the behavior of different rock types differs to some extent when exposed to weathering cycles under dry and saturated conditions. A multivariate linear regression analysis was used to predict the changes in the physical and mechanical properties of different rock types. It was been shown that with some cautions, the obtained correlations can be generalized for practical cases and can be used to predict the change of rock physical and mechanical properties during the lifetime of rock engineering projects. Such predictions have a high potential of applicability in quite different types of natural stone applications in cold climates. From the stability of structures created in rock materials to the durability of structures created by different natural stones.

Energy Performance Simulation in Buildings Composed of Natural and Organic Materials Within the Moroccan Rural Areas of the Atlas Mountains

The construction field uses up over one-third of the global energy consumption and contribute to 40% of CO2 emissions according to the International Energy Agency (IEA) and the 2020 annual reporter of United Nation, Goal 11 (Make cities inclusive, safe, resilient and sustainable) which discusses sustainable, safe and efficient buildings. Therefore, Morocco has a commitment to this program by publishing the law 47-09 of energy efficiency. This work aims to study the energy efficiency of two types of building, a conventional and a natural building. Conventional building is constructed using concrete, while the natural one uses sand clay and straws. As for the technique of making the natural building, it perpetually follows the same approach accustomed in rural zones of Atlas Mountains in Morocco. In this research we also simulate, temperature and humidity variation inside these buildings using TRNSYS software. Sketch Up software was employed to design these houses. The weather database is used for a typical meteorological year (TMY). In the case of natural building, many building configurations were simulated: roof insulation, floor insulation, different types of glazing and sun protection. What's more, the thermal comfort is revealed to be more conspicuous in the case of natural building.

New Regression Models For Evaluating The Tensile Strength of Some Natural Building Stones Using The Indirect Tensile Tests and P-Wave Velocity

The full text of this preprint has been withdrawn by the authors while they make corrections to the work. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.

Toward healthier, sustainable, medium density housing, through a return to natural materials

<p>Medium density housing can be built sustainably using natural materials. These homes are healthy to live in and have minimal impact on the environment. Increasing demand, diminishing available land, climate change and unsustainable building practices all contribute to a growing housing crisis. The list of manufactured materials such as asbestos, PVC and formaldehyde, that are hazardous to us and our planet continues to grow. Many modern homes are not fit for purpose, being poorly insulated, damp mould inducing toxic buildings, recognised as a major contributor to poor health, and being detrimental in their manufacture to the environment. Until recently, natural building materials, perceived as inferior to modern manufactured products, have been considered unsuitable for modern building. The RADIUS¹ solution cycle is developed from this research as an organised design led process. Research driven by design, then through Analysis and Discussion, Inform Design, so as to Utilise new findings to Solve the conundrum. Historically, natural material structures last for hundreds and in some cases thousands of years. Just as ancient history can show us the way with materials, perhaps recent history can suggest answers to better medium density design, the hexagon is trialed here as one possible alternative site configuration. Global interest in natural materials in developed countries is growing, the higher labour cost is no longer considered problematic, being offset by the significant material cost and environmental impact savings, health benefits and an estimated building life expectancy exceeding 200 years. New Zealand as an advocate of healthy living and conservation of nature should lead the world by example in this field in which it is currently under-represented. A composite wall and floor of straw, clay, aggregate, sand and lime is readily available, renewable, sustainable and works synergistically to maintain correct moisture levels and inhibit mould. I present two housing developments as proof of concept that natural building materials offer new typologies and a healthy sustainabale way forward.</p>

Toward healthier, sustainable, medium density housing, through a return to natural materials

<p>Medium density housing can be built sustainably using natural materials. These homes are healthy to live in and have minimal impact on the environment. Increasing demand, diminishing available land, climate change and unsustainable building practices all contribute to a growing housing crisis. The list of manufactured materials such as asbestos, PVC and formaldehyde, that are hazardous to us and our planet continues to grow. Many modern homes are not fit for purpose, being poorly insulated, damp mould inducing toxic buildings, recognised as a major contributor to poor health, and being detrimental in their manufacture to the environment. Until recently, natural building materials, perceived as inferior to modern manufactured products, have been considered unsuitable for modern building. The RADIUS¹ solution cycle is developed from this research as an organised design led process. Research driven by design, then through Analysis and Discussion, Inform Design, so as to Utilise new findings to Solve the conundrum. Historically, natural material structures last for hundreds and in some cases thousands of years. Just as ancient history can show us the way with materials, perhaps recent history can suggest answers to better medium density design, the hexagon is trialed here as one possible alternative site configuration. Global interest in natural materials in developed countries is growing, the higher labour cost is no longer considered problematic, being offset by the significant material cost and environmental impact savings, health benefits and an estimated building life expectancy exceeding 200 years. New Zealand as an advocate of healthy living and conservation of nature should lead the world by example in this field in which it is currently under-represented. A composite wall and floor of straw, clay, aggregate, sand and lime is readily available, renewable, sustainable and works synergistically to maintain correct moisture levels and inhibit mould. I present two housing developments as proof of concept that natural building materials offer new typologies and a healthy sustainabale way forward.</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>