[Paper Review] Characterization of Surface Deformation Behavior, Mechanical and Physical Properties of Modified-clay Bricks

David N. Githinji, Charles Kyuti Nzila+4 more|arXiv (Cornell University)|Oct 21, 2016

Masonry and Concrete Structural Analysis4 citations

TL;DR

This study investigates the mechanical, physical, and surface deformation behavior of clay bricks modified with sawdust and polystyrene. Using Particle Image Velocimetry (PIV), it shows that increasing non-clay content reduces bulk density, compressive and flexural strength, while increasing porosity and water absorption; deformation in modified bricks becomes non-uniform and localized near the load point before failure, spreading progressively as failure approaches.

ABSTRACT

The demand for building material is ever increasing owing to population growth. Compacted clay bricks are an important integral building material especially for low cost durable and affordable housing segment. This is a valued building material since its properties can be modified to suit various loading conditions. In this paper, the mechanical and physical properties of clay bricks modified with varying proportions of sawdust and polystyrene are determined. Increment of non-clay material proportion in the modified-clay bricks increases their porosity and water absorbency while their bulk densities, compressive and flexural strengths decreases. The use is made of Particle Image Velocimetry (PIV) method to assess the surface deformation behavior of the modified-clay bricks under uniaxial compressive loading. The distribution of surface deformation as assessed through PIV method is relatively uniform in pure-clay bricks while modified-clay bricks indicates a non-uniform deformation localized near the loading point at low strains. The strain distribution progressively spread out in the modifiedclay brick as the failure point is approached.

Motivation & Objective

• To evaluate the mechanical and physical properties of clay bricks modified with sawdust and polystyrene.
• To assess the surface deformation behavior of modified-clay bricks under uniaxial compressive loading.
• To correlate changes in material composition with variations in porosity, water absorbency, and strength properties.
• To understand the evolution of strain distribution in modified bricks using advanced imaging techniques.

Proposed method

• Clay bricks were fabricated with varying proportions of sawdust and polystyrene as additives.
• Mechanical properties including compressive and flexural strength were measured using standard testing procedures.
• Physical properties such as bulk density and water absorption were quantified through laboratory testing.
• Surface deformation behavior was analyzed using Particle Image Velocimetry (PIV) under uniaxial compressive loading.
• Strain distribution patterns were visualized and mapped over time to assess deformation localization.
• Data were collected and analyzed to correlate material composition with mechanical and physical performance.

Experimental results

Research questions

• RQ1 How does increasing the proportion of sawdust and polystyrene affect the compressive strength of clay bricks?
• RQ2 What is the impact of non-clay additives on the porosity and water absorption of modified-clay bricks?
• RQ3 How does the surface deformation behavior differ between pure-clay and modified-clay bricks under uniaxial compression?
• RQ4 Where is deformation localized in modified-clay bricks at low strain levels, and how does this evolve as failure approaches?
• RQ5 To what extent does PIV analysis reveal non-uniform strain distribution in modified-clay bricks?

Key findings

• Increasing the proportion of non-clay materials (sawdust and polystyrene) significantly reduced the bulk density of clay bricks.
• Compressive strength decreased with higher non-clay content, indicating a trade-off between lightweighting and structural performance.
• Flexural strength also declined as the proportion of sawdust and polystyrene increased in the brick matrix.
• Porosity and water absorbency increased with higher non-clay content, suggesting greater permeability in modified bricks.
• PIV analysis revealed that pure-clay bricks exhibited relatively uniform surface deformation under load.
• In modified-clay bricks, deformation was initially localized near the loading point at low strains and progressively spread out as failure approached.