română ALIDA ABDULLAH, SHAMSUL BAHARIN JAMALUDIN, MAZLEE MOHD NOOR, KAMARUDIN HUSSIN
Abstract
This paper presents the influence of natural fibre content on the mechanical properties of coconut fibre based-green composites. The mixture ratio of cement:sand by weight was fixed at 1:1. Coconut fibre was used as reinforcement and added to cement matrix to replace the sand composition. Cement matrix was reinforced with 3wt. %, 6wt. % and 9wt. % of coconut fibre by mixing and curing process. Composites were cured in water for 7, 14, and 28 days. It was observed that the composite reinforced with 9wt. % of coconut fibre demonstrated the highest strength of modulus of rupture and compressive strength.
Keywords
coconut fibre, construction, fibres, composites, portland cement
DORINA ISOPESCU, IULIAN ASTANEI
Abstract
The article presents a comparative analysis on the evaluation of two building systems for strength structures made with timber. The analysis is performed on a structural module commonly used for execution of construction, ground floor and attic, with temporary housing function.
Structural finite element analysis evaluates tensions, deformations and displacements for the characteristic structural elements, highlighting the advantages and disadvantages of using each building system.
In the last part are drawn conclusions based on results, outlooks and recommendations for further developments.
Keywords
wood, conventional structure, framing structure
DORINA ISOPESCU, OANA STĂNILĂ, IULIAN ASTANEI, CĂLIN CORDUBAN
Abstract
Wood as building material shall comply with the concept of sustainable development and provides the association between economic growth and environmental protection. Physical and mechanical properties of wood have a large number of values determined by the influences of an extended number of factors.
The article presents a description of wood properties required for design of wooden construction elements, and an analysis of the results obtained by testing laboratory specimens, according to standards requirements in force for simple bending, tensile and compression. Finally conclusions and recommendations are based on the results.
Keywords
timber elements, bending, tensile, compression, laboratory test
ZHITAO CHEN, YINGZI YANG, YAN YAO, YANGCAN WU
Abstract
Quasi-static compressive strength and dynamic impact compressive response of PVA fiber reinforced cement-based composite (PVA-FRCC) with different water binder ratio were studied. The quasi-static compressive strength decreased with increasing water binder ratio. The split Hopkinson pressure bar (SHPB) was used to obtain the dynamic impact compressive response of PVA-FRCC. The results showed that the stress-strain relationship of PVA-FRCC with different water binder ratio performed obvious strain rate effect. The deformation capacity of PVA-FRCC under dynamic load was improved with the increase of water binder ratio. The energy absorption capacity also performed rate dependency; as water binder ratio increase, the energy absorption capacity of PVA-FRCC was weakened.
Keywords
water binder ratio; PVA-FRCC; dynamic mechanical properties; SHPB
GABRIEL OPRIŞAN, NICOLAE ŢĂRANU, MIHAI BUDESCU, IOANA ENTUC
Abstract
Fibre reinforced polymer (FRP) composites are currently successfully implemented to strengthening of reinforced concrete (RC) beams improving their structural response to frequent loading conditions. The most utilized techniques are based on prefabricated composite plates bonded to the tension side with adhesives or by bonding quasi-unidirectional fabrics made of carbon fibre reinforced polymer (CFRP) composites or glass fibres fabrics impregnated with polymeric resins.
An experimental program has been carried out at The Faculty of Civil Engineering and Building Services Iaşi, to verify a number of strengthening solutions and reveal the working conditions, failure types and the structural efficiency of the proposed systems. The structural response has been evaluated through testing the RC beams under four points loading scheme. The difference in structural behaviour of unstrengthened and strengthened beams has been revealed on both loading bearing capacity and stiffness. The experimental results have been compared to those obtained by numerical modeling.
Keywords
plate bonding, failure modes, carbon fibres, numerical modeling, structural response
ANCUŢA BORLEA (TIUC), TIBERIU RUSU, SILVIU IONESCU, OVIDIU NEMEŞ
Abstract
Revaluation of wastes in the soundproofing material domain has a major international and national importance from a technical, economical and ecological point of view. This paper presents researches on the determination of the sound absorption coefficient dependent upon frequency, for every sample, thus determining the phonic absorption capacity of every resulted material. Materials were obtained by including some materials considered as wastes – pine sawdust and recycled rubber particles, in a polymer type organic matrix. The samples were made of reinforcement material and polyurethane binder, in different proportions and of different thicknesses.
Keywords
composites, noise, sound absorption, wastes, absorption coefficient