A new gelling material: properties of recycled aggregate concrete under conditions of complete cement replacement using steel slag, ore slag and fly ash

Description

This study investigates the material properties of different types of Soil Solidification Rock (SSR) in comparison with Portland Cement (OPC), using techniques such as X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The strength and calcium-silicon ratio of the SSR paste was determined, and its overall quality was comprehensively evaluated. Under the condition of 9% SSR incorporation, recycled aggregate completely replaced natural aggregate, allowing for an in-depth analysis of the effects of different SSR types on the mechanical properties and sulfate resistance durability of recycled aggregate concrete (RAC). The results indicate that factors such as the water-binder ratio, calcium-silicon ratio, and the content of fly ash and steel slag significantly affect SSR performance. The optimal hydration reaction occurred with a water-cement ratio of 0.55. Additionally, when the calcium-silicon ratio was below 3, higher values correlated with increased 28-day strength of SSR mortar. Consequently, the calcium-silicon ratio can serve as a key index for evaluating SSR quality. Soil Solidification Rock Recycled Aggregate Concrete (SSR RAC) with approximately 30% fly ash content achieved an unconfined compressive strength (UCS) exceeding 15 MPa. However, fly ash and steel slag contents above 30% led to reduced compressive strength. For fly ash content of 30% or less, increasing fly ash content improved sulfate corrosion resistance in SSR RAC. Furthermore, the metal oxide content in the SSR RAC should be controlled within 20% to 30% for optimal performance.

Categories

Funding

Licence