Effect of Cementitious Materials on the Engineering Properties of Lightweight Aggregate Mortars Containing Recycled Water

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Construction

Background:

• Growing demand for high-strength, lightweight concrete in modern construction.
• Generation of significant industrial by-product water from ready-mixed concrete equipment washing.

Purpose of the Study:

• To investigate the feasibility of recycling industrial wastewater in concrete production.
• To evaluate the performance of lightweight ternary cementitious mortars (TCMs) using recycled water and supplementary cementitious materials.

Main Methods:

• Recycling equipment wash water as pre-wetting and mixing water for lightweight aggregate.
• Substituting ordinary Portland cement (OPC) with blast furnace slag powder (BS) and fly ash (FA) in TCMs.
• Assessing fluidity, compressive strength, tensile strength, drying shrinkage, and carbonation depth.

Main Results:

• Lightweight TCMs with BS and FA achieved 28-day compressive strengths of 47.2-51.7 MPa, exceeding the control specimen (45.9 MPa).
• 28-day tensile strengths ranged from 2.81-3.20 MPa, showing a 13.7-29.5% improvement over the control.
• The optimal mix (5% BS and 5% FA) demonstrated superior compressive strength, tensile strength, and carbonation resistance.

Conclusions:

• Recycled industrial wastewater can be effectively utilized in lightweight concrete production.
• Incorporating blast furnace slag powder and fly ash enhances the mechanical properties and durability of lightweight TCMs.
• The developed TCMs offer a sustainable and high-performance alternative for the construction industry.