Due to its low water/cement ratio, high-strength concrete has a more pronounced early-age autogenous shrinkage. This thesis studies how to mitigate that by means of pre-soaked lightweight aggregate, various fractions and steel fibers. In the experimental part of the study, we measured the autogenous and total shrinkage of high-strength concrete, and used the results to calculate the contribution of drying shrinkage. We also measured the compressive strength of hardened concrete mixtures, and studied the influence of lightweight aggregate and steel fiber content on the compressive strength.
Internal curing with pre-soaked lightweight aggregate proved to be the best shrinkage mitigator.
We found out that the concrete which was reinforced with steel fibers and included internal water reservoirs in the form of pre-soaked tuff of 2 to 4 mm had the lowest shrinkage and the highest compressive strength of all the compared concrete mixtures.