Core-to-Cubic Strength Ratio for Historical-Like Concrete

Coring is considered to provide the best estimate of concrete compressive strength in existing structures and commonly used calibrate Non-Destructive Moderately Destructive Techniques. Historical concrete, produced pre-code period until ‘20s, significantly differs from modern due lack standardization, improper rules thumbs aggregate shape (round, smooth often excessively large aggregates) proportioning. Therefore, applicability procedures calibrated on a historical one, also coring, an issue that needs be discussed. In this paper, experimental campaign historical-like i.e. with same defects as aims at identifying reliability drilled cores effect round aggregates. The results show standard cannot directly applied concrete: suffer scale effects (core diameter) cutting damage material much more than concrete. detail, core-to-cubic ratio, codes assume range 0.70-0.85, dimension aggregates found inside larger range, 0.70-1.00, and, opposed decreasing increases. Besides, diameter core have relevant pointing out affects for This latter result, which further research, points concretes may rather different ones probably need are