Lightweight Reactive Powder Concrete Containing Expanded Perlite

Area of Science:

• Materials Science
• Civil Engineering
• Concrete Technology

Background:

• Reactive powder concrete (RPC) is a high-performance cementitious composite.
• Lightweight concrete aims to reduce density while maintaining mechanical properties.
• Expanded perlite (EP) is a lightweight aggregate with potential for concrete applications.

Purpose of the Study:

• To investigate the properties of lightweight concrete made with RPC and varying volumes of expanded perlite (30-60%).
• To evaluate the effects of EP on density, compressive strength, water absorption, and freeze-thaw resistance.
• To determine the optimal content of EP for RPC applications.

Main Methods:

• RPC mixes were prepared with EP content ranging from 30% to 60% by volume.
• Key properties including density, compressive strength, water absorption, and freeze-thaw resistance were tested.
• Microstructure and aggregate-matrix interaction were analyzed.

Main Results:

• Lightweight concrete with 30% EP achieved a density of ~1900 kg/m³ and compressive strength >70 MPa with low water absorption (3.3%).
• Higher EP content (45-60%) did not reduce density due to EP's low crushing resistance and required longer mixing times.
• The lightweight RPC exhibited excellent freeze-thaw resistance in the presence of de-icing salt.

Conclusions:

• RPC with up to 30% EP can produce lightweight concrete with desirable properties.
• Higher EP content is not recommended due to reduced performance and increased mixing challenges.
• The compact microstructure and aggregate-matrix bonding contribute to the excellent durability of lightweight RPC.