Optimization of Cement-Based Mortar Containing Oily Sludge Ash by Response Surface Methodology

Area of Science:

• Civil Engineering
• Materials Science
• Environmental Engineering

Background:

• Petroleum extraction generates significant oily sludge, posing disposal challenges and environmental concerns.
• Traditional disposal methods for oily sludge are often costly and environmentally detrimental.
• Developing sustainable uses for industrial waste like oily sludge is crucial for circular economy principles.

Purpose of the Study:

• To investigate the feasibility of using oily sludge ash (OSA) as a partial replacement for cement in civil construction mortar.
• To experimentally determine the optimal replacement percentage of OSA and water-to-cement ratio for producing high-performance mortar.
• To analyze the mechanical properties and water absorption characteristics of cement-based mortars containing OSA.

Main Methods:

• Cement was partially replaced with OSA at concentrations ranging from 0% to 20% by weight.
• Water-to-cement (w/c) ratios were varied between 0.4 and 0.8, keeping sand content constant.
• Mortar samples were tested for compressive strength and water absorption over a 28-day period.
• Variance analysis was employed to assess the influence of OSA and w/c ratio on mortar behavior.

Main Results:

• The inclusion of OSA in cement-based mortar mixtures significantly enhanced mechanical strength.
• A linear increase in the water absorption rate was observed with the addition of OSA.
• Variance analysis confirmed the statistical significance of OSA and w/c ratio effects on mortar properties (p < 0.05).

Conclusions:

• Oily sludge ash can be effectively utilized as a sustainable additive in cement mortar production.
• Optimal performance, balancing strength and absorption, was achieved with 8.19% OSA replacement and a w/c ratio of 0.52.
• This research offers a promising solution for managing oily sludge waste while producing valuable construction materials.