Filler technology for low-carbon high-dimensional stability concrete

In a concrete mix, a minimum paste volume is needed to ensure that there is sufficient paste to fill the voids between aggregate particles and provide excess paste for forming paste films on aggregate surfaces. However, in order to decrease the carbon footprint and increase the dimensional stability of the concrete, it is desirable to reduce the cementitious paste volume and cement content to as low as possible. Herein, it is proposed to employ the filler technology of adding a filler, which is as fine as cement, to fill into the voids so that the cementitious paste volume could be reduced to lower than the usual minimum. For feasibility study, a number of trial concrete mixes with different amounts of limestone fines added as a filler to replace an equal volume of cementitious paste were produced for testing. By so doing, some low-carbon high-dimensional stability concretes with the cementitious paste volume lowered to 20% or 18% of concrete volume, carbon footprint substantially reduced, and dimensional stability significantly improved are developed.