| description abstract | High early strength (HES) portland cement concrete (PCC) is widely used in pavement preservation because it permits a quick reopening to traffic. However, these repairs often deteriorate faster than normal paving concrete, prompting a need to investigate the mechanisms leading to poor performance. In this study, six HES concrete mixtures with varying cement factors and accelerator dosages were subjected to isothermal calorimetry, strength testing, drying shrinkage, and various durability-related tests. The effects of the cement content and accelerator dosage on concrete strength and durability were then investigated. It is hypothesized that mixtures containing high cement contents and large dosages of accelerators will demonstrate poor performance. Testing results indicate that a target minimum compressive strength of 1,800 psi in 6 h, as required by certain state highway agencies, can be obtained using any of the studied mixtures, regardless of the cement content or accelerator dosage. Only one mixture successfully achieved all durability-related testing targets; however, only one of the mixtures catastrophically failed, and the remaining four mixtures all performed reasonably well. Thus, it cannot be concluded that HES portland cement concrete is inherently nondurable and that high cement content and accelerator dosage are incongruent with durable concrete. Possible explanations for the anecdotal poor field durability are explored. | |
