Enhancing Mechanical Properties and Microstructures of Mass-Manufactured Sand Concrete by Incorporating Granite...

Area of Science:

• Materials Science
• Civil Engineering
• Environmental Science

Background:

• Construction dust, particularly granite powder, poses a pollution challenge.
• This waste material can be repurposed as a supplementary cementitious material.
• Utilizing granite powder in concrete offers a sustainable solution for waste management and material enhancement.

Purpose of the Study:

• To investigate the effects of granite powder as a cement replacement on concrete's mechanical properties and microstructure.
• To evaluate the potential of granite powder in mitigating autogenous shrinkage and improving pore structure.
• To understand the role of granite powder in the hydration process of concrete.

Main Methods:

• Granite powder was incorporated as a partial cement replacement in concrete mixtures.
• Mechanical properties (compressive and flexural strength) and autogenous shrinkage were tested.
• Microstructure, pore structure, and hydration products were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP).

Main Results:

• Concrete strength increased with granite powder content up to an optimal level (5% replacement), showing significant gains in compressive (17.6%) and flexural (20.9%) strength at 28 days.
• Autogenous shrinkage was reduced by 19.7% with 10% granite powder replacement.
• Porosity significantly decreased with up to 10% granite powder, and SEM analysis indicated granite powder acts as a nucleation site for hydration products without altering their type.

Conclusions:

• Granite powder effectively enhances concrete's mechanical properties and reduces autogenous shrinkage.
• The optimal content for strength enhancement is around 5% cement replacement.
• Granite powder acts as a microcrystalline nucleation agent, refining the pore structure and improving concrete performance, offering a sustainable construction material solution.