Design of Dry-Stacked Blocks with High Thermal Resistance for Exterior Walls
Creators: Mohammadi, Marzieh
Publisher: name: University of Alberta Library
Year: 2024

<p>The escalating energy consumption of buildings highlights the significance of adopting energy-efficient building design and construction practices. The growing demand for higher thermal resistance within building envelopes also necessitates innovative solutions for energy-efficient building components. Dry-stacked masonry blocks have gained considerable attention as a viable construction material for masonry walls, primarily due to their rapid assembly, absence of mortar, and diminished reliance on skilled labor. However, there has been a notable absence of a comprehensive review of these blocks&#39; thermal performance. Furthermore, there is a distinct lack of evaluation pertaining to the thermal performance of dry-stacked blocks within cold climate zones.<br>
This study fills the gap in existing literature by conducting a thorough review of the thermal performance of dry-stacked masonry blocks. The review includes considerations tailored for cold climate zones and insights into both market-available and research-based dry-stacked blocks. Additionally, to address the thermal performance of dry-stacked blocks, this study develops two novel dry-stacked blocks: a simple block and a composite block. The composite block incorporates an integral insulation within its components, while the simple block does not include any insulation. These blocks have been meticulously designed for optimal performance within cold climate zones. Using the finite element method, the thermal resistance of these blocks is carefully assessed. Detailed comparative analyses are conducted on both simple and composite block walls, alongside a conventional masonry wall. Additionally, the performance of the composite block is examined in relation to existing market counterparts.<br>
Based on the review, the employment of novel materials such as cement and palm oil clinker powder mixture, rubberized concrete, and concrete including recycled masonry aggregates and expanded polystyrene (EPS) show promise in enhancing both thermal resistance and compressive strength. However, these materials are still relatively novel and costly. Furthermore, the review underscores the significance of incorporating insulation into the block structure. Filling block cavities with foam proves to be more effective in enhancing thermal performance than the removal of exterior side webs.<br>
The review highlights that in cold climate zones, the integral insulation and cavity walls play crucial roles in achieving thermal efficiency. In such cases, the thermal performance of masonry assemblies with integral insulation is primarily governed by the insulation component. Hence, the utilization of composite blocks with integral insulation offers significant advantages for buildings located in cold climate zones. <br>
The simulation results show a significant impact of thermal bridging on the thermal resistance of the simple block, resulting in an 11% decrease in the effective thermal resistance (R-value) of a simple block wall assembly when compared to the composite block wall assembly. Furthermore, in comparison to a conventional masonry wall with hollow grouted units and the same insulation thickness, the composite block wall exhibits a 24% higher R-value by eliminating thermal bridging through insulation, while the simple block wall demonstrates an 11% higher R-value due to different ties’ shape and grouted masonry cores. When comparatively assessing the composite block against existing market options, it emerges as the superior choice in terms of thermal resistance. Consequently, the composite block is ideal for fast construction, limited labor, and lightweight requirements Conversely, the simple block is the preferred choice in situations where complicated manufacturing tools are unavailable.</p>