In healthy people, Al uptake from alum‐treated water is low. Several epidemiological studies have associated aluminum (Al) in drinking water with the incidence of Alzheimer's disease, despite the fact that water provides a relatively minor proportion of intake compared with other dietary sources. For Al from alum‐treated drinking water to contribute markedly to blood Al, it would have to be much more bioavailable, i.e., more readily taken up from the gut into the bloodstream, than Al from food. The relative bioavailabilities of Al naturally present in food and in alum‐treated drinking water (ATW) were determined using 29 healthy volunteers who drank, during two‐day periods, ATW or pure water, with and without citrate, while on a controlled diet. Only 1–2 percent of the daily intake of Al came from ATW and only 0.3–0.4 percent of the Al in ATW was absorbed by the body—the same percentage as that absorbed from food. It was estimated that drinking 1.6 L/d of ATW containing 140 μg/L Al would contribute only 0.4–1.1 percent of the lifetime body burden of Al.

Reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) have been increasingly used in asphalt mixtures. The use of RAP and RAS in asphalt mixtures not only reduces the consumption of virgin materials, conserves energy, and protects the environment but also improves the rutting resistance of asphalt pavements. However, as more recycled materials are used in asphalt mixtures, there is increasing concern over their potential negative effects on the mix cracking resistance. To improve the cracking resistance of asphalt mixtures with high RAP/RAS contents, one of the approaches considered is using recycling agents to potentially restore performance properties of the aged binder. This project was conducted to evaluate the effect of a recycling agent (RA), known as Hydrogreen, on the long-term field performance of high RAP and RAS mixes. The field study consisted of three test sections, each constructed by placing a dense-graded surface lift at a depth of 4.5 cm (1.75 in.) on SR 7 near Harrisonville, Missouri, in August 2013. The three mixes placed in the three test sections included: (1) a control mix containing 30% RAP using an SBS-modified PG 70-22 binder with no RA; (2) a 40% RAP mix using the same PG 70-22 binder with RA; and (3) a 25% RAP and 5% RAS mix using a neat PG 64-22 with RA. This paper presents data collected during the construction of the test sections, laboratory performance testing results, and early field performance. The research results showed that the recycling agent could be used in the 40% RAP and 25% RAP and 5% RAS mixes to achieve similar construction quality, laboratory performance, and early field performance to the 30% RAP control mix. As these sections are still in service, it is recommended that they continue to be monitored in order to evaluate their long-term performance.

The Superpave® mix design system includes design criteria for a range of mixes with nominal maximum aggregate sizes (NMASs) between 9.5 and 37.5 mm. Many agencies in the United States have expressed an interest in using a 4.75-mm NMAS mix. Such a mix could provide benefits; that is, it should provide a very smooth riding surface, could be used for thin lift applications, could correct surface defects (leveling), could decrease construction time, could provide a use for manufactured screening stockpiles, and could provide a very economical surface mix for facilities with low traffic volumes. A study was done to establish the standard mix design criteria needed for 4.75-mm mixes. On the basis of the findings of the study, the recommended Superpave mix design criteria include a specified gradation control of 30% to 54% passing on the 1.18-mm (No. 16) sieve and 6% to 12% passing the 0.075-mm (No. 200) sieve. During design, the following were recommended: a design air void content of 4%, minimum voids in mineral aggregate (VMA) of 16% for all traffic levels, maximum VMA of 18% for mix designs with more than 75 gyrations, voids filled with asphalt (VFA) of 75% to 78% for mix designs with 75 gyrations and above, and VFA of 75% to 80% for mix designs with 50 gyrations. The results of the study showed that 4.75-mm NMAS mixes can be successfully designed. These types of mixes should provide economical mixes for low-volume roadways.

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