SCEBs - University of Colorado Boulder

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The testing methodology proposed in this report is intended to provide a systematic process of evaluating potential soils, by applying both geotechnical and structural engineering principles. Given the availability of a suitable soil, following the suggested guidelines and criteria will ultimately lead to a satisfactory SCEB. This report and included testing methodologies are intended to form the foundation on which a robust best practice standard can be developed. The author does not intend to suggest that all issues concerning earthen building are addressed directly or that the results achieved from the provided case studies can be directly extended to any soil other than the specified soils in the study. However, many of the fundamental concepts and procedures can be applied more broadly. Currently, the technical level of understanding is limited to the assumption that regardless of the exact soil composition of the mix in question, if the mix produces a high quality product then it is suitable given proper testing. The testing matrix proposed herein attempts to further define acceptance criteria and streamline the process required to initiate a SCEB building project. Identifying the availability of a suitable soil or soil mix for use in SCEB production is the first step to starting a successful project. While many options are possible, the soils of interest in this report are referred to as clayey soils and well-graded sands. The soils are formally classified as per the United Soil Classification System (USCS). Documenting the soil classification in relation to its performance in SCEB production will hopefully lead to better understanding of this relationship. Current building codes offer no suggestions or guidelines for selecting a suitable soil based on classification. Identifying the optimal soil mix or recipe based on a selection of different 2
soils must be defined to standardized building codes. Several factors are important; material availability, soil gradation, particle size/shape/angularity, optimal moisture content, presence of cohesive forces, and the ultimate performance of the block produced. Due to high regional variability, any combination of these factors will be encountered when investigating a potential soil mix. This variability is partly what motivates this thesis and the proposed SCEB material testing methodology. The original intent of this thesis was to develop a step-by-step procedure for building with earth, but the need for a more dynamic, iterative approach was quickly realized. Through experience with different soils and a review of the available literature, the author anticipates that comprehensive studies and collaborative research in different locales will lead to a framework for standardizing earthen building technology. Several Native American nations in the western United States have begun looking at compressed earth building technology as a sustainable technology with increased interest. Projects initiated by the Crow Tribe in Montana and the Ute Mountain Ute Tribe in Colorado have received funding from the Bureau of Indian Affairs (BIA) within the Division of Energy and Minerals Development (DEMD), and coordinated with research programs at the University of Colorado, Boulder. The Tribes are able to take advantage of the resources mined locally on their reservation, implement a successful building project, and provide housing and jobs for members of their community. In addition to the added housing brought in by these programs, the projects have the potential to stimulate the economic growth within the Tribes. Earthen building techniques offer more than just a proven construction material. Because of their relatively low production cost, earthen block production can offer a 3
Page 1 and 2: A Proposed Best Practice Method of
Page 3 and 4: Krosnowski, Adam Davis (M.S., Depar
Page 5 and 6: Table of Contents 1. Introduction .
Page 7 and 8: Table of Figures Figure 2.1: World
Page 9: 1. Introduction The demand for sust
Page 13 and 14: move more towards sustainable “gr
Page 15 and 16: 2.1. SCEB Technology Advantages The
Page 17 and 18: latent heat of vaporization. The ef
Page 19 and 20: sedimentation (jar) test, ball drop
Page 21 and 22: opportunities for water to alter th
Page 23 and 24: 3.2. Testing Methodology Flow Chart
Page 25 and 26: transported sealed in airtight five
Page 27 and 28: Figure 3.2: Gilson Testing Screen M
Page 29 and 30: infer the clay content. Figure 3.7
Page 31 and 32: potential for minimizing costs. Det
Page 33 and 34: calculate bulk unit weights of the
Page 35 and 36: 3.9. Modulus of Rupture: Three-Poin
Page 37 and 38: Figure 3.16: SCEBs soaking in water
Page 39 and 40: samples from the Dead Man‟s Curve
Page 41 and 42: previous experience, visual inspect
Page 43 and 44: one week intervals during the initi
Page 45 and 46: UCS [psi] UCS [psi] 1000 800 600 40
Page 47 and 48: UCS [psi] UCS [psi] 1000 800 600 40
Page 49 and 50: Lower Limit: 1 part cement, 1 part
Page 51 and 52: Percent Passing Soil #15: Hydromete
Page 53 and 54: the sample and not the entire soil
Page 55 and 56: Large blocks were produced from two
Page 57 and 58: The large blocks produced were kept
Page 59 and 60: decreased by 23-25% over the course
Page 61 and 62:
Figure 4.23: UMU Mini-Blocks; Five
Page 63 and 64:
Average UCS [psi] 2000 1600 1200 UM
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Clayey soil is often mined and tran
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Figure 5.1: Full Block in 3-Point B
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nature will increase the level of c
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this point of testing. The testing
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Average Large Block UCS [psi] 800 7
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Figure 5.13: Aspect Ratio Test, Fiv
Page 77 and 78:
Figure 5.17: Aspect Ratio Test, One
Page 79 and 80:
E [ksi] 35 30 25 20 15 10 y = 23.85
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The equation of the trend-line was
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of optimizing a soil mix design. Of
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plasticity. They also do not offer
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the SCEB strongly influence its com
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specimens will be tested for compre
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P f Pf [ psi] 2 A force at fail
Page 93 and 94:
Coduto, D. P. 1999. Geotechnical En
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8.2. Crow Tribe Case Study Test Dat
Page 98 and 99:
8.2.2. Schmidt Hammer Test Data R V
Page 100 and 101:
UMU Sample #15 1:3 (6 x 12 x 3 5/8)
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SCEBs - University of Colorado Boulder

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