What ingredient, used cleverly very sparingly by the Romans, largely determines durability of concrete?
Roman concrete candidate for "the most durable building material in human history". In contrast, modern concrete exposed to saltwater deteriorates within decades. Compressive strengths for modern Portland cements are typically at the 50 MPa level and have improved almost ten-fold since 1860. There are no comparable mechanical data for ancient mortars, although some information about tensile strength may be inferred from the cracking of Roman concrete domes. These tensile strengths vary substantially from the water/cement ratio used in the initial mix. At present, there is no way of ascertaining what water/cement ratios the Romans used, nor are there extensive data for the
Nathan Cleverly 5,000 strong, the fight went the full 12 round distance as Cleverly won every round on all three judges scorecards comfortably (120-108), to retain his world title.Cleverly showed he clearly had the better workrate and technique, winning every round dominantly. Karpency was not a threat as many thought, but showed durability in lasting the distance, having previously not been stopped. This was the first time in 12 fights that Cleverly fought in Cardiff. According to puch stats, Cleverly landed 374 of his 987 punches (38%), while Karpency landed only 87 in 692 thrown (13%), showing very little workrate. On 5