Spall damage repair using 3D printing technology

Concrete road surfaces may crack due to shrinkage from drying. Often, cracks are induced at predetermined locations to solve this problem. However, the impact loads from vehicles are concentrated on these pre-induced transverse joints, often resulting in palm-sized spall damage. Repairing this damage with cast-in-place concrete leads to indirect losses from road blockages that occur during curing. This research presents a new method of repairing spall damage that minimizes indirect loss. A three-dimensional concrete patch is prepared in advance and placed over the damaged area. When using cast-in-place concrete to repair spall damage, road use must be restricted for a minimum of seven days. The proposed method reduces road closure to 2 h. According to the US Department of Transportation guidelines, the proposed method is estimated to reduce indirect losses from road repair from USD $140,000 to USD $1700. A three-dimensional concrete patch attached to a damaged surface can withstand a shear load of up to 15.7 MPa. The proposed method can withstand at least 91% of this load. Moreover, given the friction between the patch and the damaged surface, the structural stability of a concrete patch in response to shear loads may be even greater than 91%. This study presents the proposed methodology and discusses its economic value and structural practicality.