This document summarizes research on using selfing and crossing theory to alter the strength of blended concrete mixes. Selfing involves blending two mixes of the same type but different strengths, while crossing uses mixes of different types. The study aims to identify blending ratios and time lags that allow partially set concrete to be workable and achieve target strengths when blended. Testing of M20 and M30 mixes alone and blended showed strength improvements when selfed or crossed, with crossing providing larger gains. It was concluded that concrete can maintain strengths up to delays of 180 minutes through blending, and bonding agents can further extend workability to 12-16 hours.