Results 1 - 10 of 307
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[en] The article Experimental investigation of the axial strength of glued-in rods in cross laminated timber, written by Boris Azinović, Erik Serrano, Miha Kramar, Tomaž Pazlar, was originally published online without Open Access.
[en] The article A microstructural insight into the hygro-mechanical behaviour of a stabilised hypercompacted earth, written by Agostino Walter Bruno, Céline Perlot, Joao Mendes, Domenico Gallipoli, was originally published online without Open Access.
[en] The article Determination of transfer stress from ruptured pre-load galvanised tendons in tanks and bund walls, written by Fin O’Flaherty. Paul Lambert. Pal Mangat. Vincenzo Starinieri, was originally published online without open access.
[en] Reliable methods are necessary to assess the corrosion level to establish links between structural performance and reinforcement corrosion in concrete structures. Hence, in this study, a set of naturally corroded bars were subjected to metallic brushing, acid immersion, and sandblasting for rust removal. Additionally, 3D optical, CT scanning, and weight loss measurements were used to evaluate the levels of corrosion. The results indicate that sandblasting is an optimal cleaning method. Weight loss measurements are sufficient when detailed information about corrosion is not required, and 3D scanning is preferred if information on corrosion variation along the bar is needed.
[en] Engineered bamboo, produced through the technique of gluing and reconstituting, has better mechanical properties than round bamboo and some wood products. This paper studies the flexural performance of laminated beams produced with timber and engineered bamboo. The six-layer beams were made from Douglas fir, spruce, bamboo scrimber and laminated bamboo, or a combination of these. It is confirmed that glued-laminated wood beams produced with wood of weak strength, like spruce, can be strengthened by gluing engineered bamboo lumbers on the outer faces, thus achieving better utilization of the fast growing economic wood species. Flexural failure of the laminated beams was primarily triggered by tensile fracture of the bottom fiber in mid-span, followed by horizontal tearing beside the broken surface. No relative slip between layers was observed before failure, therefore the flexural capacity of the laminated beams can be predicted using equilibrium and compatibility conditions according to the plane section assumption.
[en] The performance of slag and fly ash in hydrated cementitious materials depends on the degree of reaction developed at the evaluated age. Several methods for the determination of the reaction degree of supplementary cementitious materials are available, among which the selective dissolution method is one of methods developed the earliest. This is a direct method that aims to quantify the amount of unreacted slag or fly ash in the sample by applying a selective acid attack. The degree of reaction is obtained from the comparison between the remaining unreacted SCM, which should not dissolve, and the total amount initially included in the mix. This recommendation indicates suitable procedures for computing the degree of reaction by selective dissolution of cement pastes containing slag and fly ash. Specific considerations are indicated for necessary corrections due to the imperfect selective dissolution when the procedure is applied to hydrated cement paste.
[en] Drilling resistance measurement (DRM) is recognised as an important on-site micro-invasive procedure for assessment of construction materials. This paper presents a detailed investigation of user-controlled variables and their influence on drilling resistance. The study proves that the ratio of penetration rate/rotational speed is proportional to drilling resistance. Data from Bath stone and an artificial reference stone demonstrates how different materials can be compared using their intrinsic specific energy. It is also shown that adjusting drilling settings does not significantly change drilling measurement variability. However, settings producing high drilling resistance can significantly contribute to drill bit wear. A theoretical framework in which tests can be optimised without compromising the ability to compare data is presented. The framework is of high significance to the conservation industry and will promote a more effective use of DRM. DRM is a minimally invasive procedure particularly appropriate for sensitive heritage structures. Its use can provide the essential mechanical property data required for evaluation of surface consolidation products and specification of repair materials.
[en] This paper provides the first report of capacitance-based nondestructive cement-based material defect detection. It is based on the use of the fringing electric field (2 kHz) of a capacitor that comprises the cement-based material (cement paste slab, 250 × 250 × 9.31 mm3) and two relatively small copper electrodes separated from the slab by an electrically insulating polymer film. Due to the fringing field through the slab, the apparent permittivity is high, thus enabling the measured capacitance to be sensitive to defects. The through-thickness capacitance, which relates to the apparent relative permittivity of the cement-based material, is measured using electrodes that sandwich the slab. The in-plane capacitance is measured using closely spaced parallel co-planar electrodes. A region (150 × 150 × 9.31 mm3) of the slab is rendered defective by containing gypsum pellets, the porosity of which causes the apparent relative permittivity of this region (142) to be lower than that of the adjacent perfect region (199). To determine the position of the boundary of the defective region, the capacitance is measured using a series of electrodes, with each electrode geometry consisting of N squares linearly aligned perpendicular to the boundary. The capacitance is measured in order of increasing N, which is sufficient for the electrode to cover regions on both sides of the boundary. The capacitance increases linearly with N in each region, with the slope being different for the two regions. The intersection of the extrapolated linear curves of the two regions gives the position of the boundary.