According to Official Guinness Records,
The most concrete blocks broken while holding a raw egg is 28 and was achieved by Kevin Bergquist (USA) at Dojo Academy in Brandenton, Florida, USA, on 3 October 2015. Kevin began practising martial arts when he was 5 years old and currently owns his own martial arts studio.
For a complete list of 2015 records, please visit 2015 Guinness Records in United States.