تطبيقات استخدام النفايات الصناعية في تحضير المواد الإسمنتية الصديقة للبيئة بالمملكة العربية السعودية

الملخص EN

Cement industry is one of the hazardous industries which account for environmental and health risks in addition to the greenhouse gas emissions.

The aim of this study is to develop nano-structured eco-friendly cementitious materials by utilizing the fly ash (FA) resulting from burning the heavy fuel oil in power plants in Saudi Arabia.

Ordinary Portland cement (OPC) was partially replaced with 70 wt% of (FA).

FA was substituted by different ratios of nano metakaolin (NMK) ranging from 2-14%.

A series of tests have been conducted on the developed mixes according to ASTM standards at 28 days of curing including (compressive strength – flexural strength – water absorption –initial and final setting times).

Differential scanning calorimeter (DSC) was used to study the phase composition/decomposition and the microstructure was investigated by scanning electron microscope (SEM) equipped with energy dispersive analytical X-ray unit (EDAX).

The results revealed that the partial replacement of cement by 70 wt% of FA has reduced both compressive and flexural strengths by about 45%, in addition; the water absorption has been increased by about 175% as compared to the OPC.

The substitution of FA by 10 wt% NMK has compensated the loss in mechanical strengths by about 75%.

Furthermore, NMK has considerably improved the microstructure and reduced the water absorption by 86%.

The study concluded that, it is possible to substitute 70 wt% of cement for the production of eco-friendly cement with improved mechanical performance achieving 88% of the corresponding performance of the hydrated OPC.

The developed composite is a green binder and can be considered for various construction applications and will benefit the national economy of the Kingdom