Experimental Research on Resistance to Frost of Rubberized Concrete

2012 ◽  
Vol 193-194 ◽  
pp. 1414-1417
Author(s):  
Jin Hua Xu ◽  
Si Li Chen ◽  
Ying Wang ◽  
Ming Liu
Keyword(s):  
Elasticity Modulus ◽  
Fine Aggregate ◽  
Rubberized Concrete ◽  
Portland Cement Concrete ◽  
Destructive Testing ◽  
Dynamic Elasticity Modulus ◽  
Dynamic Elasticity ◽  
Different Grain Size ◽  
Different Content ◽  
Non Destructive

According to mixture proportions design, rubber concrete specimens were produced, which were used for test of resistance to frost. In this study, different grain size and different content rubber were mixed in Portland cement concrete. Quick freeze-thaw test was carried to rubberized concrete. The research shows that appropriate proportional fine aggregate replaced by the discarded tires powder and grain can improve concrete resistance to frost, although concrete compressive strength, flexural strength and dynamic elasticity modulus decrease with increasing of rubber content. The improving effect of rubber powder is better than rubber grain. Furthermore, it is demonstrated that the dynamic elasticity modulus obtained by Non-destructive testing can commendably evaluate the frost resistance of rubberized concrete.

scholarly journals Non-Destructive Assessment of the Dynamic Elasticity Modulus of Eucalyptus nitens Timber Boards

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 269
Author(s):  
Alexander Opazo-Vega ◽  
Víctor Rosales-Garcés ◽  
Claudio Oyarzo-Vera
Keyword(s):  
Elasticity Modulus ◽  
Selection Process ◽  
Sustainable Construction ◽  
Eucalyptus Nitens ◽  
Dynamic Elasticity Modulus ◽  
Dynamic Elasticity ◽  
Static Modulus ◽  
Structural Applications ◽  
Non Destructive ◽  
Local Variability

Eucalyptus nitens is a fast-growing wood species with a relevant presence in countries like Australia and Chile. The sustainable construction goals have driven the search of structural applications for Eucalyptus nitens; however, this process has been complicated due to the defects usually presented in these timber boards. This study aims to evaluate the dynamic elasticity modulus (Exd) of Eucalyptus nitens timber boards through non-destructive vibration-based tests. Thirty-six timber boards with different levels of knots and cracks were instrumented and tested in a simply supported condition by measuring longitudinal and transverse vibrations. In the first stage, the Exd was calculated globally through simplified normative formulas. Then, in a second stage, the local variability of the Exd was estimated using operational modal analysis (OMA), finite element numerical simulations (FEM), and regional sensitivity analysis (RSA). The positive correlation found between the global static modulus of elasticity and Exd suggests that non-destructive techniques could be used as a reliable and fast alternative for the assessment of bending stiffness. Finally, the proposed method to estimate the local variability of Exdt based on the combination of OMA, FEM, and RSA techniques was useful to improve the structural selection process of timber boards for lightweight social housing floors.

scholarly journals Modelling of Airport Rigid Pavement for Complex Configuration of Landing Gears and for a Large Spectrum of Cement Concrete

2013 ◽  
Vol 8-9 ◽  
pp. 235-242
Author(s):  
Radu Cojocaru ◽  
Andrei Radu ◽  
Mihai Budescu
Keyword(s):  
Finite Element ◽  
External Load ◽  
Elasticity Modulus ◽  
Poisson Ratio ◽  
Landing Gear ◽  
Recycled Aggregates ◽  
Rigid Pavement ◽  
Dynamic Elasticity Modulus ◽  
Finite Element Software ◽  
Dynamic Elasticity

The purpose of this paper is to develop new design diagrams in order to complete the actual Romanian standard. This addendum is justified by the fact that the current design diagrams are elaborated for a single value of the E - dynamic elasticity modulus (in Romanian standard E = 30000 MPa) and of the Poisson ratio (in Romanian standard ν = 0.15). Therefore the diagrams from the Romanian standard NP034-99 do not permit the design for other types of concrete cement with improved characteristics with elasticity modulus E 30000 until E = 50000 MPa or of the Rolled Compacted Concrete (RCC) with Poisson ratio ν = 0.25 or of the other concrete types as cement concretes with recycled aggregates or steel fibre reinforced concrete. The first part of the paper presents the stress design methodology based on the finite element software and on the parameters which interfere in the design calculation. In addition to the diagrams from the Romanian standard which apply only to an external load up to a four wheel bogie, the diagrams with loads with six wheel bogie are introduced. Further are shown the differences between the stress calculated with single values from the actual Romanian standard and the stress calculated with the exact values of the considered parameters [E dynamic elasticity modulus and the Poisson ratio]. The study relies on the specific load of modern aircrafts (like Airbus - A380, Boeing - B777) that have six footprints tire in the landing gear structure. In the end, the article brings forward a graphic comparison analysis between the diagrams of the Romanian current standard and the ones conducted in the present study by using FEM (Finite Element Method). Furthermore, a design case study exemplifies the method used to obtain the slab thickness for an airport rigid pavement structure using an external load from a complex landing gear with six footprints tire.

Dynamic elasticity modulus for low-carbon steel in the climatic temperature range

1986 ◽  
Vol 18 (7) ◽  
pp. 917-920 ◽  
Author(s):  
Kh. M. Khanukhov ◽  
V. S. Polyak ◽  
G. I. Avtandilyan ◽  
P. L. Vizir
Keyword(s):  
Carbon Steel ◽  
Elasticity Modulus ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Dynamic Elasticity Modulus ◽  
Temperature Range ◽  
Climatic Temperature ◽  
Dynamic Elasticity
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