Compressed Stabilized Earth Block Research Articles

Compressive Strength Characteristics of Compressed Stabilized Earth Block (CSEB) Units and Walls

This paper is mainly focused on compressive strength behavior of Compressed Stabilized Earth Block (CSEB) units and CSEB walls. Compressed Stabilized Earth Block (CSEB) is a rectangular block used in wall construction. The ingredients of CSEB are soil, cement, fine aggregate, crusher dust, and a small amount of water. These blocks have less energy consumption and carbon emission, and they provide improved thermal insulation. In addition, they use local resources and disseminate appealing aesthetics with elegant profile and uniform size. Due to these advantages CSEB can be used as a green construction material. This research aims to study the strength characteristics of CSEB wall in compression and evaluate the suitability of CSEB walls as load bearing walls in structures. This research studies physical and mechanical characteristics of CSEB units made from red residual soil of Lele (Lalitpur) with 8% cement for stabilization. This paper discusses the compressive strength behavior of walls constructed of size 0.660m x 1.100m x 0.220m using CSEB units in cement sand mortar and stabilized mud mortar separately which were tested after 28 days. The experimental values after laboratory testing of CSEB masonry wall with height to thickness ratio 5:1 for cement sand mortar (1:6) and stabilized mud mortar (stabilized with 8% cement and 16% extra sand) separately are compared with relevant values from different codes. Results obtained from compressive strength tests of masonry walls constructed in the laboratory and those values from different codes concerning the strength of masonry unit and mortar are compared and found to be in agreement. The comparison of laboratory results with codal provisions of design of masonry walls illustrate that CSEB masonry walls can be designed in the similar way as brick masonry walls.

Shear capacity of interlocking compressed stabilized earth block masonry panels

An experimental study was conducted to investigate the shear performance of reinforced and unreinforced interlocking compressed stabilized earth block (ICSEB) masonry wall panels. Forty-eight wall panels were fabricated using Auram 295 blocks and subjected to diagonal-compression. The influence of coir fibres, channel block, type of reinforcement (steel and bamboo) and arrangement (mesh and vertical) on wall shear behavior were studied. Cracking patterns, failure modes, load-deformation response and shear capacity were analyzed and discussed. The feasibility of using conventional masonry analytical equations in estimating the shear load capacity of wall panels was also evaluated. The test results demonstrated that wall panels without bamboo/steel reinforcement failed suddenly in a brittle manner and split into two parts, whilst bamboo/steel reinforced grouted wall panels behaved in a more ductile manner and remained intact after the failure, irrespective of presence of fibres. The incorporation of fibres effectively increased the shear load and deformation ability of wall panels, irrespective of the variables examined. The panels reinforced with steel/bamboo showed a significant improvement in shear load capacity of about 20.33% to 162.94% and in deformation capacity of around 48.47% to 258.29% when compared to the panels without reinforcement. The adopted analytical equations inaccurately predicted the shear capacity of wall panels.

Suitability of using areca nut fiber as reinforcing material in compressed stabilized earth blocks (CSEB) for low-cost housing

An economical and cost-effective replacement for conventional building materials is Compressed Stabilized Earth Block (CSEB). However, they are vulnerable to erosion and cracking, particularly in humid settings. The use of natural fibers as reinforcement is found effective in overcoming this problem. Areca nut fiber which is a complete waste material in countries like Bangladesh and India is also a sturdy, adaptable, and water-resistant natural fiber that makes it the perfect choice as fiber reinforcement material for CSEBs. In this article, the strength performance analysis of areca nut fiber as a reinforcement material for CSEBs is investigated, where 0%, 0.85%, 2%, 5%, and 8% of areca nut fiber is mixed with soil that is stabilized with 10% cement. CSEB specimens of 4″ × 4″ × 4″ size have been made and tested for compressive strength, tensile strength, bulk density, and water absorption. It is observed that there is an 83.76% increase in compressive strength and an 8.89% increase in splitting tensile strength for 0.85% of areca nut fiber content specimen cured for 90 days. The water absorption was found a minimum of 9.07% for 0.85% areca nut fiber content and the minimum density of the block was observed at 1810 kg/m3 for the optimum percentage of 0.85% mix. The study indicates that using 0.85% of areca nut fiber content in stabilized CSEB shows a significant improvement in the strength characteristics of compressed stabilized earth blocks.Graphical

Satisfaction and representations of raw earth habitat: a case study of Auroville, India

ABSTRACT This exploratory study presents, for the first time, an analysis of how residential satisfaction (RS) can be related to earthen building materials. The study utilizes an ongoing world-renowned project in Auroville, India, which aims to promote the environmentally friendly Compressed Stabilized Earth Block (CSEB) as a substitute for non-ecological fired-brick. The research employs the semantic differential (SD) method as a means to examine satisfaction. It seeks to explain the limitations of CSEB usage compared to fired-brick and compares satisfaction levels among different groups of residents. For the first time, it has been proven through our findings that CSEB has a significant positive impact on RS, while fired-brick demonstrates no influence on RS. The restricted use of CSEB cannot solely be attributed to its level of house-building-material satisfaction (HBMS), as CSEB surpasses fired-bricks in HBMS rating. Despite this, houses constructed with CSEB offer equivalent levels of RS to those constructed with fired-bricks, sparking a resourceful discussion on various interpretations related to RS theories. One perspective posits that CSEB technology may not be widely adopted, while others emphasize the importance of supporting its development despite the anticipated positive behavior toward it.

Axial load behavior of unreinforced and reinforced hollow interlocking compressed stabilized earth block masonry walls

This study investigates the axial load behavior of unreinforced and reinforced hollow interlocking compressed stabilized earth block masonry walls. Sixty walls were constructed and tested under axial compression. The variables include block type (unreinforced and coir fibre reinforced), grout condition (ungrouted and grouted), channel blocks, reinforcement type (steel bars and bamboo splints) and configuration (vertical and mesh type). The results show that addition of coir fibres significantly increase the axial load capacity and ductility of walls, regardless of all other variables considered. Grouting of masonry cores increases the load capacity of unreinforced and fibre-reinforced walls (without bamboo/steel reinforcement), however slightly affecting the deflection capacity. The channel block had a detrimental effect on the load and deflection capacity of both unreinforced and reinforced walls. Bamboo/steel reinforced vertically significantly contributed to the axial load and deformability of walls, despite the presence or absence of channel blocks. Both bamboo and steel reinforced walls behaved in a similar manner; yet bamboo splints showing slightly lesser load and deflection capacity than steel. The axial load and deflection capacity of bamboo reinforced grouted walls are about 78.54% to 90.00% and 79.50% to 94.60% respectively as compared to steel reinforced counterparts. Bamboo/steel mesh reinforced walls with channel blocks exhibited better performance compared to corresponding specimens with only vertical reinforcement. However, the improvement was marginal, due to larger spacing between the horizontal reinforcement. Nevertheless, the presence of horizontal reinforcement greatly improved the failure behavior by restraining the buckling of vertical reinforcement. Overall, fibre and vertical steel reinforced grouted wall specimens without channel blocks (FSVRGMW) showed the best performance in terms of compressive strength. The design equations in MSJC-11 predicted the load capacity of unreinforced and reinforced masonry walls more conservatively. Finally, it can be stated that MSJC-11 recommendation of internally reinforced grouted walls must be treated as unreinforced walls, if no horizontal reinforcements was provided, is not reasonable.

Potential of waste rice husk ash and cement in making compressed stabilized earth blocks: Strength, durability and life cycle assessment

Compressed stabilized earth block (CSEB) is an environmentally safe building material that is required as a sustainable alternative to traditional building materials. This research aims to investigate the suitability of rice husk ash (RHA) and cement for producing sustainable CSEB. RHA is a readily available waste product in rice-producing countries and using this waste product as a partial replacement for cement in CSEB has both environmental and economic benefits. To discern the ideal combination of stabilizers, three cement contents (4%, 6%, and 8% by wt. of dry soil), and five RHA contents (0%, 5%, 10%, 15%, and 20% by wt. of dry soil) are considered. The performance of CSEB is assessed regarding strength and durability. Strength characteristics were assessed by performing unconfined compression, split tensile, and flexure tests, and durability characteristics were assessed through water absorption, wet compressive strength, submersion, and efflorescence tests. There is an improvement of 224–1515% in dry compressive strength, 63–1190% in split tensile strength, and 112–732% in flexural bending strength (compared to unstabilized specimens) due to the addition of stabilizers. Considering strength properties, the optimum RHA content was 5% for 4% cement content, whereas for 6% and 8% cement content, it was found to be 10%. Considering durability, stabilized samples showed a reduction in water absorption of 2.8–73.4% compared to unstabilized samples. The strength and durability requirements provided in various codes have been met by the combination of 4–8% cement and 5–10% RHA. CSEB incorporating lower cement content with 5–10% RHA was found to perform better than that produced using higher cement content which indicates the suitability of RHA as a partial cement replacement. Furthermore, microstructural and thermal analysis has been performed on CSEBs fabricated with RHA, and the results revealed the existence of a higher concentration of C–S–H gel in CSEB stabilized with 8% cement and 10% RHA. Life cycle analysis conducted on a one-story house showed that CSEB is superior to fired clay bricks considering environmental and economic aspects. Based on the outcome, it is evident that CSEB stabilized with RHA, and cement could serve as a sustainable building material.

Compressed Stabilized Earth Block Incorporating Municipal Solid Waste Incinerator Bottom Ash as a Partial Replacement for Fine Aggregates

This research explores the potential of using municipal solid waste incinerator bottom ash (MSWIBA) as a partial replacement for fine aggregate and ordinary Portland cement (OPC) as a stabilizer in the production of compressed stabilized earth blocks (CSEBs). The study investigates the effect of varying levels of cement content (ranging from 0% to 10%) and MSWIBA content (ranging from 0% to 25%) on the strength and durability of CSEBs. The strength characteristics of CSEBs were evaluated through tests such as wet and dry compressive strength, flexural strength, water absorption, and stress–strain behavior, while durability was tested through wetting–drying cyclic tests. The results indicated that CSEB blocks made with 20% MSWIBA content and 10% cement were able to fulfill strength criteria. Additionally, using these blocks could result in cost savings of 8% during construction when compared to using fired clay bricks (FCB). Furthermore, varying the cement content while maintaining a constant proportion of MSWIBA showed a significant change in the stress–strain behavior and a cost analysis performed for CSEBs stabilized with the optimal quantity of MSWIBA-OPC combination showed that they can be a viable alternative to conventional earth blocks, providing an eco-friendly, sustainable, and cost-effective solution for construction initiatives.

Flexural behavior of hollow interlocking compressed stabilized earth-block masonry walls under out-of-plane loading

The present study aims to investigate the out-of-plane flexural behavior of hollow interlocking compressed stabilized earth block (ICSEB) masonry walls reinforced with bamboo and steel bars. The effect of grouting, channel block and reinforcement layout (vertical and mesh type) was assessed. A total of thirty masonry walls were fabricated using fibre reinforced blocks and categorized into five groups: two groups of ungrouted and grouted (without bamboo or steel reinforcement) masonry wall specimens and three groups of grouted masonry wall specimens reinforced with bamboo splints and steel bars. All the specimens were subjected to a constant pre-compression load while lateral load parallel to bed joints was gradually applied until failure. In addition, the experimental moment capacity of reinforced masonry walls was compared with the MSJC-11 formulations to assess the applicability. A statistical regression analysis was then performed on the test results to predict the ultimate moment and deformation capacity of all wall specimens. Test results suggest that grout alone has significantly contributed to the load carrying capacity of wall specimens but with a marginal improvement in deformability. While, channel blocks has no significant effect on load carrying capacity of reinforced grouted masonry wall specimens. Bamboo splints and steel bars as internal reinforcements are very effective in preventing the sudden failure and also enhancing the flexural resistance of masonry walls. Steel mesh showed the highest load carrying capacity, lateral deformation and energy absorption capacity. The addition of bamboo or steel reinforcement combined with grout improved the ultimate load carrying, deformation capacity and energy absorption of walls by 114.88%–260.55%, 19%–35.52% and 168.25%–489.28% respectively.The MSJC-11 code overestimated the moment capacity of reinforced masonry walls; whereas the regression models developed accurately predicted the moment capacity and lateral deformation of the masonry walls.

Compressed stabilized earth block: environmentally sustainable alternative for villages housing

Construction materials contribute to environmental pollution and the impoverishment of natural raw materials. The villages of Upper Egypt were exposed to high thermal loads owing to their geographical location. Moreover, the current building materials do not comply with the principles of sustainability and environmental adaptation of the residents of these buildings. Therefore, attaining admission to one sustainable building material in Upper Egypt and using it as an environmentally compatible, inexpensive, accessible, and easy building material for the users of these blocks is essential. In this study, the author selected various sites in Upper Egypt, analyzed climate and urban data, and after that, suggested prototypes with many variables and measured using the DesignBuilder V5 computer simulation program to select an optimal building type. Reached that can be saved energy about 40:50% and decreased annual discomfort hours more than 50%, finally, discussed with community members by a questionnaire on societal acceptance. The research concluded that building with compressed stabilized earth block is an environmentally sustainable solution applied in residential areas in the villages of Upper Egypt to reduce deficiencies in environmental adaptation.

An Innovative Approach to Produce Soil-Based Building Products

Soil has been used as a building material in different forms, such as mud, adobe, rammed earth, and bricks. Compressed Stabilized Earth Block (CSEB), a form of soil blocks with different additives including cement, fly ash, and lime, is a sustainable building material with many advantages compared to other conventional building materials. The usual practice of past researchers in producing CSEB was to add different materials like sand to the soil to control its clay and silt (finer) content. A high level of finer content is not desirable when it comes to the strength and durability of CSEB. This study proposes to reduce/ extract the finer content in the soil by washing it using a conventional concrete mixing machine.

Ranking of walling materials using eco-efficiency for tropical climatic conditions: A survey-based approach

All over the world, “Construction” is an important sector that consumes a significant amount of resources and produces a lot of waste. Buildings as a whole share nearly one-fourth of total electricity generation in tropical countries that results in adverse effects on the natural environment and their national economies. Enhancing the building energy efficiencies relies on material and technology selection that complement the local climatic conditions. Compressed Stabilized Earth Blocks are considered as an innovative and proven building envelope upgrade that enhances building efficiencies both economically and environmentally considering their cradle-to-gate phase. However, the cradle-to-grave life cycle impacts of Compressed Stabilized Earth Blocks compared to conventional walling materials are yet to be assessed in tropical climatic conditions for long-term decision making. Accordingly, the objective of this study is to compare compressed Stabilized Earth Blocks with conventional walling materials such as Burnt Clay Bricks and Cement Sand Blocks. The life cycle thinking approach was integrated with eco-efficiency analysis to compare and evaluate the above-mentioned materials considering their entire life span from cradle to grave. Accordingly, Compressed Stabilized Earth block has been selected as the more efficient material with environmental benefits. Moreover, since it can be used as a walling element even without the application of plaster, costs and environmental impacts could be further reduced when used without plastering. The findings of this research will encourage building developers, contractors, and practitioners in selecting the most desirable material for their projects considering costs and environmental impacts of the material life cycle.

Are low-income mass housing envelops energy efficient and comfortable? A multi-objective evaluation in warm-humid climate

This study evaluates and compares the performance of the commonly constructed mass housing envelops in India with alternative building envelop constructions. These alternative construction scenarios are created with a material library comprising of the available alternative roofing and walling system combinations including some common emerging construction technologies standardized and advocated by the Building Materials and Technology Promotion Council of India. The common trend of housing envelop constructions in the country involves ordinary burnt brick walls and reinforced cement concrete roofing and beam-column system which is referred to as the base case building envelop in our study. We consider initial investment costs, thermal comfort perception and the initial embodied energy in a multi-objective evaluation framework for assessing free running building envelops. Rat trap bonded brick walls, glass fibre reinforced gypsum construction, light gauge framed steel (LGFS) constructions, monolithic concrete (MC) construction system, reinforced concrete ribbed roof and compressed stabilized earth block (CSEB) walls and CSEB filler roof slabs make repeated appearances in the multi-objective optimal solution sets or Pareto optimal solution sets. CSEB construction has lowest initial embodied energy, LGFS gives minimal thermal discomfort whereas MC construction system reports least construction cost. A predominance of lean envelop constructions is observed in the Pareto optimal solution sets considering minimization of construction cost, thermal discomfort and construction embodied energy.

Evaluation of compressed stabilized earth block properties using crushed brick waste

This study investigates the engineering properties of compressed stabilized earth blocks (CSEBs) incorporating crushed brick waste as alternative to soil-sand mixture as well as sand. The work was undertaken in two phases: in first phase, the influence of crushed brick waste to replace soil-sand mix without jeopardizing the original performance along with resistance against sulfate attack has been highlighted. Further, microscopic studies were performed to examine the compounds developed. Then, the influence of crushed brick waste particle size and replacement ratio to replace natural sand has been studied. The results show that inclusion of crushed brick waste in soil-sand mixture significantly improved the block performance, especially under wetting–drying cycles and sulfate attack. The X-Ray Diffraction (XRD) and Scanning electron microscope (SEM) studies confirmed that inclusion of crushed brick waste leads to better resistant against external attacks. Crushed brick waste particle size and replacement ratio has significant influence on block strength and water absorption. The addition of 20% crushed brick waste with particle size 0/4.75 mm increases the compressive and flexural strength; beyond that the resistance decreases due to inferior properties of crushed brick waste. On the other hand, removal of powder content negatively affected the block strength. The replacement of sand with very fines content up to 20% is encouraging beyond that the strength decreases drastically due to higher porosity and water absorption of crushed brick waste. Irrespective of crushed brick waste particle size, water absorption increases with replacement ratio.

A performance assessment on Compressed Stabilized Earth Block (CSEB) using geo – polymeric binders

The development of the country mainly depends on Rural Development. About 55% of rural peoples still live in earth building. According to the US Green Building Council, the building sector accounts for 39% of the global emission of CO2. If new technologies were not adopted means the emission could be doubled by the year 2050 according to United Nation Environment Program (UNEP). New technology is required to sustain the environment and earth materials. In India, One of the recently developing technology is Compressed Stabilized Earth Block (CSEB). This CSEB technology replaces the usage of conventional burnt clay bricks. In this Context, The earth materials are not widely used in CSEB because it includes the vital part of industrial wastes. The characteristics of CSEB with Granulated Blast Furnace Slag (GGBFS), Fly Ash of class-F and coir fiber are to be investigated. Nowadays, the controlling, management and disposal of waste materials are a difficult task. The Flyash-F is an industrial waste material that is obtained from a thermal power plant and it contains a low amount of CaO. GGBFS is also an industrial waste obtained from the quenching molten iron slag in steel industries. About 20-25% of dry volume soil is replaced by a combination of Flyash and GGBFS with the addition of a geopolymer solution. Both the waste materials bring the CSE-Block as eco-friendly to the environment and cost-effective. Besides, The CSEB exhibits high strength, low creep, very minimum water absorption and good erosion resistance. In this paper, we are experimentally investigating the compressive strength and water absorption nature of CSEB with varying ratios of binders and Geo-Polymeric solution.

Assessment of energy demand and greenhouse gas emissions in low rise building systems: Case study of five building systems built after the Gorkha Earthquake in Nepal

Buildings are responsible for significant energy consumption and greenhouse gases (GHG) emission. This study aims to assess energy consumption and CO2 emission in five low rise building systems of buildings used for the reconstruction of earthquake-resistant houses in hilly regions of Nepal after Gorkha Earthquake. The Ecoinvent dataset version 3.5 and software tool OpenLCA version 1.8 has been used to assess the energy consumption and CO2 emission due to the construction of the buildings after the earthquake. The study considers four stages of lifecycle assessment starting from firstly, material production and transportation stage; secondly, the construction of the building stage; thirdly, operation of the building stage to finally, demolition stage of the residential buildings with different construction materials. The results of the study show that Reinforced Cement Concrete (RCC) system demands 1.69 times higher energy than the Compressed Stabilized Earth Block (CSEB) system, whereas, the RCC system emits 1.64 times higher CO2 equivalent emission than Interlocking Block (IB) building system throughout their lifecycle. This outcome of the study would be useful to the policymakers to choose the right structural system of the building with appropriate construction materials for the construction of houses which will give less impact on the environment.

Effectiveness of saw dust ash and cement for fabrication of compressed stabilized earth blocks

This study focuses on investigating the effectiveness of Saw Dust Ash (SDA) and cement for fabricating strong and durable Compressed Stabilized Earth Block (CSEB) using coarse-grained soil. CSEB is a viable alternative to traditional Fired Clay Brick (FCB) as warranted by reduced associated pollution and increased energy efficiency. Four different cement contents (4%, 6%, 8% and 10%) and different SDA contents (0–10%) are considered to discern optimum combination to fabricate satisfactory CSEB in terms of compressive strength, shear strength, deformation behavior and durability. For a particular cement content, addition of SDA increases the compressive strength gradually, reaches a maximum value which is identified as optimum content and thereafter begins to drop. Optimum amount of SDA was found 4% for 4% cement, 6% for 6–8% cement and 8% for 10% cement. Addition of cement-SDA is found to increase the compressive strength of the blocks by 21–147% compared to that of unstabilized earth blocks. Moreover, optimum combination of cement-SDA provides CSEBs with maximum density and minimum porosity. Inclusion of cement-SDA is found effective in increasing angle of internal friction, ϕ of the stabilized mix. With addition of optimum SDA (4–8%) with cement, mixtures were found to exhibit ϕ>58o. CSEBs with optimum amount of cement-SDA is found to provide maximum modulus of elasticity, peak strain and failure strain. Addition of 6–8% SDA with 6–10% cement is found durable in terms of water absorption (<15%), wet compressive strength (>700 kPa) and wet-to-dry strength ratio (>0.33). Based on all the parameters and obtained test results, it can be concluded that cement-SDA stabilized earth blocks can be efficiently considered as a suitable construction material.

English

English

Effectiveness of fly ash and cement for compressed stabilized earth block construction

For saving natural resources, reducing pollution and increasing energy efficiency, Compressed Stabilized Earth Block (CSEB) can serve as a suitable alternative to conventional Fired Clay Brick (FCB). In this study, suitability of industrial waste, Fly Ash (FA) is assessed along with cement as stabilizers for producing CSEBs with coarse grained soil. Different combination of cement and FA (5–10% cement and 5–25% FA; by weight of dry soil) was considered to prepare CSEBs for finding the optimum mix composition in terms of strength, durability, deformation characteristics and cost effectiveness. Furthermore, strength and durability test results are compared to the design criteria reported in Indian Standard, Sri Lankan Standard, Standard Australia, British Standard and Malaysian Standard for assessing its viability as construction material. With the increase in cement content, strength of the blocks gradually increases; however, at a definite cement content, addition of FA increases strength up to a certain limit and then begins to drop. Inclusion of 7–8% cement and 15–20% FA is found to provide adequate dry compressive strength (>5 MPa), wet-to-dry compressive strength (>0.33) and enough durability in terms of water absorption (<20%) as recommended by British Standard and Standards Australia. The behavior of the CSEBs were also analyzed through microstructural investigation, where SEM images were taken to ascertain the morphologic and anatomic changes that occurred at different fly ash contents. At a definite cement content, with the increase of FA, peak strain and failure strain increase; thereby indicating an improved straining capacity of the blocks due to inclusion of FA. Moreover, modulus of elasticity improves with increasing amount of cement and FA for both dry and wet state. Furthermore, economic analysis of a typical house constructed with CSEBs and FCBs was performed and compared with literature. Considering all the parameters it can be concluded that CSEBs prepared with cement and fly ash as stabilizers can be used as a sustainable construction material.

Strength and Durability Characteristics of Cement-Sand Stabilized Earth Blocks

AbstractConventional building materials like fired clay brick (FCB) and concrete blocks are expensive and, in some cases, have detrimental effect on environment. Compressed stabilized earth block (...

Sharanam: Case Study of a 15 Meter Span Earthen Conical Vault

This paper presents a case study of the structural design and construction of a 15 meter span conical vault, a low rise, unreinforced masonry shell which was built with compressed stabilized earth block in the “free-spanning” vaulting technique. While large span vaults of this size are not a new contribution to the field, earthen vaults are rarely built at this scale or these proportions, and those which are tend to have greater structural redundancy. With a maximum span of 15 m, maximum rise of 2.5 m, and a thickness varying from 24 cm at the base to 17.7 cm at the crown, extensive symmetrical and asymmetrical stability analyses had to be undertaken to ensure adequate safety, particularly for construction loads and for the high potential cyclone wind conditions on the southeast coast of India. The vault was first studied with graphical thrust line analysis using an optimization method developed by the Auroville Earth Institute (AVEI) for vaults of varying thickness, then replicated with the Finite Element Thrust Line Analysis (FETLA) method. The paper will address boundary condition design, as well as the high degree of precision required in the shell construction to meet the assumptions of analysis and ensure stability. The results of this work point the way toward larger span constructions with low strength, low embodied energy materials through greater coordination of material, structural and constructive logics.