Enhancing concrete support bearing strength with strain hardening cementitious composite (SHCC) layer: an experimental study

This study investigates the potential of Strain Hardening Cementitious Composite (SHCC) as a reinforcement layer to enhance the bearing strength of concrete supports, addressing the brittle failures often observed in conventional concrete under concentrated loads. Specimens were divided into six groups (G1 to G6) to explore variables such as groove number and size, SHCC layer depth and size, and the use of anchors. The results demonstrated that incorporating SHCC layers into concrete blocks effectively reduced crack width and delayed the onset of ultimate failure. However, excessive SHCC thickness compromised stress distribution, leading to earlier and more brittle failure. Specifically, increasing the number and size of grooves enhanced bearing capacity by an average of 16.7% and 22.4%, respectively. Similarly, using appropriate size of SHCC layer improved stress distribution, resulting in a 36.2% increase in bearing capacity. Conversely, increasing SHCC depth at the expense of its size reduced bearing capacity by 29.4%, likely due to inefficient stress distribution. Although the use of anchors was intended to enhance the bond between the SHCC layer and the underlying concrete, they instead acted as stress concentrators, accelerating failure and reducing bearing strength by 17.6% on average. Similarly, while the addition of grooves and optimized SHCC block sizes led to substantial gains in Energy Absorption Capacity (EAC), other modifications, such as anchoring or inappropriate SHCC layer depths, had counterproductive effects. The study concludes with the proposal of an empirical formula to predict the bearing capacity of SHCC-reinforced structures, incorporating the key test parameters identified.