*Article* **Chloride Penetration Behavior of Concrete Made from Various Types of Recycled Concrete Aggregate**

**Wanchai Yodsudjai and Kirati Nitichote \***

Department of Civil Engineering, Kasetsart University, Bangkok 10900, Thailand; fengwcy@ku.ac.th **\*** Correspondence: kirati.ni@ku.th

**Abstract:** This research aimed to identify the link between the chloride penetration behavior of concrete made from various types of recycled aggregate from three main sources—building demolition waste (B-RCA), laboratory waste (L-RCA), and precast concrete waste (P-RCA)—and the 28-days compressive strength of natural aggregate concrete with the replacement ration 30%, 60% and 100% respectively. The results of the study revealed that the quality of recycled aggregate waste significantly impacted concrete behavior. To elaborate, finer aggregate potentially increased the inter-facial transition zone (ITZ), which is the weakness part of concrete, resulting in the concrete having less compressive strength as well as increasing amount of chloride ion penetration thought rapid test. In this research, an image processing technique, which is a simple method, was used to quantify the ITZ area of concrete. It was found that concrete with low compressive strength and high permeability values had an ITZ area significantly more than other types of concrete.

**Keywords:** construction demolition waste; recycle concrete aggregate; sustainable construction

**Citation:** Yodsudjai, W.; Nitichote, K. Chloride Penetration Behavior of Concrete Made from Various Types of Recycled Concrete Aggregate. *Sustainability* **2022**, *14*, 2768.

Academic Editors: Carlos Morón Fernández and Daniel Ferrández Vega

https://doi.org/10.3390/su14052768

Received: 27 January 2022 Accepted: 22 February 2022 Published: 26 February 2022

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