About the competition

The theme 'design & making UHPC bouncy ball' is comprehensive embodiment of material properties, design creativity and fabricated skill of an UHPC element, i.e. to contest for UHPC performance (tension properties, toughness, impact resistance, etc.), for innovative design (strong but light structure, possible structures as illustrated below), for craftsmanship (ball sphericity, dimension accuracy, surface quality, etc.).

Requirements of UHPC bouncy ball

• Ball diameter: 200±10 mm (less 190mm / over 210mm not allowed)

• Ball weight: ≤ 6,000.0 g (overweight not allowed)

• Minimum UHPC properties: compressive strength ≥ 120 MPa, tensile strength ≥ 5 MPa and maintaining ≥ 3.5 MPa at tension strain 0.15% (meet the requirements of UT05 or higher grade by standard T/CBMF 37/T/CCPA 7-2018)

• No limitations on: fiber reinforcement (types, sizes, shapes & contents), curing methods

Judging criteria

• Delivered 'Design Destription' (10pt)

• Measured ball diameter accuracy (less dimension deviation - higher score, 10pt,)

• Sphericity (deviations of the diameters in x, y, z axis with the average diameter, 10pt)

• Surface quality (hole, smoothness, pricking the hand or not, 10pt)

• Rebound height H of the ball from 2000 mm drop (H in centimeter = pt)

• Cracking width after drop (10pt)

Rebound testing

In the rebound test, the UHPC ball is dropped from a height of 2 meters to measure its rebound height., as illustrated below.

3rd Competition

3rd competition of design & making UHPC bouncy ball, organized by CCPA-UHPC and supported by Co-Nele Machinery, was held on 31-May-2024, Nanjing, China, see pictures below. 26 teams participanted the 3rd competition, 9 teams from universities (Group Y) and 17 teams from enterprises (Group Q). A new record was set with a rebound height of 90 cm in the 3rd competition. The video (4 time slower) shows UHPC ball rebound with height above 15 cm. It’s an interesting and exciting contest, attracting lot people to watch. The bouncy of UHPC ball is well showcasing what UHPC can do and how high the toughness of UHPC can be obtained.