Behaviour of strengthened timber beams using near surface mounted Basalt Fibre Reinforced Polymer (BFRP) rebars

Reinforcement of structural timber members with fibre reinforced polymer (FRP) rods offers merits over that of the conventional steel type. In recent times, near surface mounted (NSM) FRP reinforcement with timber has emerged as a promising alternative for reinforcing timber structures in both flexural and shear loading configurations. Previous investigations have shown that NSM FRP reinforcement technique has higher bond performance than externally bonded equivalents because it (NSM FRP technique) is able to utilise the full capacity of the FRP materials. In spite of these merits, the investigations and the use of this innovative technique are limited. In this paper, an experiment was conducted to investigate the bond characteristics and performance of NSM basalt FRP reinforcement with solid timber structures. In order to predict the performance of the reinforced beam structures, unreinforced control timber members of the same timber characteristics were tested. The results showed that the average bond capacity of the NSM FRP reinforced members was 16% higher than the corresponding unreinforced beams

Analysis and evaluation of post construction failures of airport apron pavement in Ghana

A new apron pavement for parking aircrafts was constructed in 2014, but major depressions occurred when used by aircrafts soon after the construction. Failure analysis revealed structural design inconsistent with the United States Federal Aviation Administration Design Code AC 150-5320-6E. The methodologies for the technical investigations of the failures encompassed field investigation (including visual condition survey), sampling core materials for verification tests, non-destructive and destructive tests to evaluate the integrity and characteristics of the pavement layers. The sample of cores tested in an accredited laboratory were inconsistent with the site tests. Air voids and Marshall Stability for wearing course were low. Binder specification should have been PG82, instead of PG76, which was not appropriate for aprons subjected to large static loads. The low air voids in the wearing course were linked with the compaction regime adopted. Fuel resistant polymer modified bitumen was adopted for the construction, without correct application techniques, thereby affecting the pavement performance. The key factors underlying the pavement failures were binder specifications, tenderness of the mix, compaction regime and structural design, which contributed to the immediate distress and possible long term performance of the pavement.Keywords: Apron Pavement, Wearing course, Cores, Air voids, Marshall stability, Compacting regime, Polymer modified bitume

Synthesis and characterization of canola oil-stearic acid-based trans-free structured lipids for possible margarine application

Incorporation of stearic acid into canola oil to produce trans-free structured lipid (SL) as a healthy alternative to partially hydrogenated fats for margarine formulation was investigated. Response surface methodology was used to study the effects of lipozyme RM IM from Rhizomucor miehei and Candida rugosa lipase isoform 1 (LIP1) and two acyl donors, stearic acid and ethyl stearate, on the incorporation. Lipozyme RM IM and ethyl stearate gave the best result. Gram quantities of SLs were synthesized using lipozyme RM IM, and the products were compared to SL made by chemical catalysis and fat from commercial margarines. After short-path distillation, the products were characterized by GC and RPHPLC-MS to obtain fatty acid and triacylglycerol profiles, C-13 NMR spectrometry for regiospecific analysis, X-ray diffraction for crystal forms, and DSC for melting profile. Stearic acid was incorporated into canola oil, mainly at the sn-1,3 positions, for the lipase reaction, and no new trans fatty acids formed. Most SL products did not have adequate solid fat content or beta' crystal forms for tub margarine, although these may be suitable for light margarine formulation