Xiaoying Pan

University of Southern California | USC

This paper presents a study on the self-healing performance of reinforced concrete beams using a new approach called engineered aggregates (EA). EA are a type of capsules that release healing agents when the concrete is cracked, without requiring any changes to the conventional concrete preparation methods. In this study, polyurethane (PU) filled E...

The existing self-healing concretes that rely on capsules require modifications to one or more traditional concrete mixing, placing, and consolidating methods. Additionally, concrete mixture designs need alterations to accommodate these self-healing capsules. This paper presents the development and characterization of a novel encapsulation method f...

This paper presents optimal self-healing configurations in concrete using a new concept referred to herein as engineered aggregates (EA). EA are hollow particles designed to carry healing agents into the cracks in concrete. The concept of EA has been developed by the authors as a cost-effective method for self-healing in conventional concrete witho...

Permeability is an important indicator of the durability of cement-based materials. Surface treatments are effective in reducing permeability, and thus improving durability. In this study, CO2 surface treatment, as a new method, was investigated explore the efficiency on cement-fly ash-slag ternary concrete. The results show that the CO2 surface tr...

Previous study has shown that CO 2 surface treatment can provide significant protective effects on cement mortar at early ages. This study examines the compressive strength, water permeability, water-vapor transmission and chloride migration of mortars after CO 2 surface treatment with subsequent lime water curing. Thermogravimetric analysis (TGA),...

Many of the degradation problems of concrete can be attributed to the weak surface layer. Surface treatment of concrete has been proven a simple and effective method to enhance the durability of concrete. In the present study, two series of portland cement mortar specimens with w/c ratios of 0.4 and 0.3 were prepared. CO2 treatment was applied to h...

In this paper, the flowability, compressive strength, hydration heat, porosity and calcium hydroxide content of cement-silica fume-fly ash-based ultra-high-strength concrete (UHSC) incorporating either nano-silica (SiO2) or nanocalcium carbonate (CaCO3) were investigated. Test results showed that the flowability of UHSC was reduced by incorporating...

Magnesium fluorosilicate, waterglass, sodium fluorosilicate, and combination of waterglass and sodium fluorosilicate were used as surface treatment agents and their interactions with the Portland cement hydrates were studied. Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR) were employed to analyze the phase chan...

The permeability of the cement-based materials can be used as an important indicator of their durability. Surface treatment is a simple way to reduce permeability and improve durability of cement-based materials. This paper studied the effects of fluosilicate and sodium silicate surface treatments on the permeability of cement-based materials using...

The permeability of the cement-based materials can be used as an important indicator of their durability. Surface treatment is a simple way to reduce permeability and improve durability of cement-based materials. This paper studied the effects of fluosilicate and sodium silicate surface treatments on the permeability of cement-based materials using...

The cement paste attached to natural aggregates has a significant effect on the quality of recycled concrete aggregates (RCAs) because it usually has higher porosity and lower strength than natural aggregates. This work attempted to improve the quality of RCAs through carbonation of the attached cement paste. During carbonation reactions, CO 2 reac...