Abstract: The use of recycled concrete aggregates (RCAs) in hot-mix asphalt (HMA) production could ease natural aggregate shortage and maintain sustainability in modern societies. However, it was the attached cement mortar and other impurities that make the RCAs behave differently than high-quality aggregates. Therefore, different upgrading treatments were suggested to enhance its properties before being used in HMA production. Disappointedly, some of these treatments had caused degradation to some RCA properties. In order to avoid degradation, a coating technique is developed. This technique is based on combining of two main treatments, so it is named as double coating technique (DCT). Dosages of 0%, 20%, 40% and 60% uncoated RCA, RCA coated with Cement Slag Paste (CSP), and Double Coated Recycled Concrete Aggregates (DCRCAs) in place of granite aggregates were evaluated. The results indicated that the DCT improves strength and reduces water absorption of the DCRCAs compared with uncoated RCAs and RCA coated with CSP. In addition, the DCRCA asphalt mixtures exhibit stability values higher than those obtained for mixes made with granite aggregates, uncoated RCAs and RCAs coated with CSP. Also, the DCRCA asphalt mixtures require less bitumen to achieve the optimum bitumen content (OBC) than those manufactured with uncoated RCA and RCA-coated with CSP. Although the results obtained were encouraging, more testing is required in order to examine the effect of the DCT on performance properties of DCRCA- asphalt mixtures such as rutting and fatigue.
Abstract: This study was carried out to evaluate the nutritional
composition of the African River Prawn (Macrobrachium
vollenhovenii) in relation to Chokor (traditional) and Altona
(improved traditional) drying techniques used in the preservation and
processing of prawns by carrying out proximate composition
analysis. The value obtained for the proximate analysis of Chokor
and Altona smoke dried prawns were; Moisture (14.90% and
15.15%), Dry matter (85.10% and 84.85%), Protein (55.80% and
58.87%), Crude fat (1.95% and 1.98%), Crude fibre (21.40% and
13.11%), Carbohydrate (0.54% and 0.54%) and Ash (19.76% and
15.86%) respectively. The proximate mineral composition of Chokor
and Altona smoke dried prawns were; Calcium (5.66% and 4.20%)
and Phosphorus (9. 22% and 6.34%) respectively. Result shows there
was no loss of nutritional value with respect to Chokor and Altona
drying techniques used in the processing of prawns.