scholarly journals 1038) On Relation Among the Compressive Strength, Pulse Velocity, Dynamic Modulus of Elasticity and the Logarithmic Decrement of Concrete by Sonic and Ultrasonic Methods(Materials, Execution)

1961 ◽  
Vol 69.1 (0) ◽  
pp. 149-152
Author(s):  
Sakichi Ohgishi ◽  
Toshiro Uchida
2011 ◽  
Vol 243-249 ◽  
pp. 165-169 ◽  
Author(s):  
Iqbal Khan Mohammad

Nondestructive testing (NDT) is a technique to determine the integrity of a material, component or structure. The commonly NDT methods used for the concrete are dynamic modulus of elasticity and ultrasonic pulse velocity. The dynamic modulus of elasticity of concrete is related to the structural stiffness and deformation process of concrete structures, and is highly sensitive to the cracking. The velocity of ultrasonic pulses travelling in a solid material depends on the density and elastic properties of that material. Non-destructive testing namely, dynamic modulus of elasticity and ultrasonic pulse velocity was measured for high strength concrete incorporating cementitious composites. Results of dynamic modulus of elasticity and ultrasonic pulse velocity are reported and their relationships with compressive strength are presented. It has been found that NDT is reasonably good and reliable tool to measure the property of concrete which also gives the fair indication of the compressive strength development.


2021 ◽  
Vol 20 (1) ◽  
pp. 52-61
Author(s):  
Harun TANYILDIZI ◽  

The mechanical properties of polymer impregnated concrete containing polypropylene fiber were statistically and experimentally examined in this study. Taguchi L9 (33) was used in this study. The variables used for experiments were selected as the polypropylene fiber ratio (0%, 1% and 2%), cement dosage (300, 350 and 400 kg/m3) and curing time (7, 14 and 28 days). After the specimens were cured at the specified curing times, they were dried at 105 ±5 °C. Then, the monomer was impregnated to the specimens for 24 hours under atmospheric conditions. The samples for the polymerization of monomer was kept within the drying oven at 60 °C for 6 hours. The compressive strength and ultrasonic pulse velocity tests of specimens, in which polymerization was applied, was conducted. Furthermore, the dynamic modulus of elasticity of samples was calculated using the ultrasonic pulse velocity. The Taguchi analysis found that the best values for the ultrasonic pulse velocity, dynamic modulus of elasticity and compressive strength were 28 days for curing, 1% for the polypropylene fiber percentage and 400 kg/m3 for the cement dosage. The Anova analysis found that the polypropylene fiber percentage had the biggest effect on the mechanical properties of polymer impregnated concrete containing polypropylene fiber.


Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 104
Author(s):  
Fernando A. N. Silva ◽  
João M. P. Q. Delgado ◽  
António C. Azevedo ◽  
Tahlaiti Mahfoud ◽  
Abdelhafid Khelidj ◽  
...  

Early deterioration of reinforced concrete foundations has been often reported in recent years. This process is usually characterized by an extensive mapping cracking process on concrete surfaces that results from several types of Internal Swelling Reaction (ISR). In this paper, a real case study of a tall reinforced concrete building with a severe deterioration process installed in its deep foundations is discussed. Laboratory tests were performed in concrete drilled cores extracted from a deep pile cap block 19 years after the beginning of construction. Tests to assess the compressive strength, the static and the dynamic modulus of elasticity, the gas permeability, and electron microscopy scanning to find out the primary mechanism responsible for the deterioration observed during in situ inspections. Chemical alterations of materials were observed in concrete cores, mainly due to Delayed Ettringite Formation (DEF), which significantly affected the integrity and durability of the structure. Dynamic modulus of elasticity showed to be a better indicator of damage induced by ISR in concrete than compressive strength. Procedures to strengthen the deteriorated elements using prestressing proved to be an efficient strategy to recover the structural integrity of pile caps deteriorated due to expansions due to ISR.


Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 414-418 ◽  
Author(s):  
Cheng-Jung Lin ◽  
Ming-Jer Tsai ◽  
Chia-Ju Lee ◽  
Song-Yung Wang ◽  
Lang-Dong Lin

Abstract The effects of ring characteristics on the compressive strength and dynamic modulus of elasticity of seven softwood species in Taiwan were examined. The results revealed good correlation between compressive strength and dynamic modulus of elasticity obtained using an ultrasonic wave technique (correlation coefficient r=0.77–0.86). Overall, compressive strength increased with decreasing ring width parameters and increasing ring density parameters. Ring density was related to compressive strength, but was not the sole factor affecting the wood strength. According to our statistical analysis, compressive strength was affected by various ring characteristics. Relationships between ring characteristics and compressive strength are influenced by the anatomic direction. Results revealed that earlywood density and minimum density in a ring are equally important variables for evaluating the compressive strength of wood.


2010 ◽  
Vol 163-167 ◽  
pp. 1655-1660
Author(s):  
Jian Zhang ◽  
Bo Diao ◽  
Xiao Ning Zheng ◽  
Yan Dong Li

The mechanical properties of high strength concrete(HSC) were experimentally investigated under mixed erosion and freeze-thaw cycling according to ASTM C666(Procedure B), the erosion solution was mixed by weight of 3% sodium chloride and 5% sodium sulfate. The mass loss, relative dynamic modulus of elasticity, compressive strength, elastic modulus and other relative data were measured. The results showed that with the increasing number of freeze-thaw cycles, the surface scaled more seriously; the mass loss, compressive strength and elastic modulus continued to decrease; the relative dynamic modulus of elasticity increased slightly in the first 225 freeze-thaw cycles, then decreased in the following 75 cycles; the corresponding strain to peak stress decreased with the increase of freeze-thaw cycles. After 200 cycles, the rate of deterioration of concrete accelerated obviously.


2010 ◽  
Vol 168-170 ◽  
pp. 2565-2570 ◽  
Author(s):  
Xu Guang Tang ◽  
You Jun Xie ◽  
Guang Cheng Long

The deterioration on sulfate attack was investigated both in physical crystallization and the chemical erosion. Specimens that suffered long-term immersion and dry-wet cycles in saturated sodium sulfate solution are compared to trace the physical attack. And the chemical erosion was conducted by comparing specimens which have been suffered long-term immersion in saturated sodium sulfate solution and saturated limestone solution. In the investigation, the non-destructive detecting indexes, such as the ultrasonic velocity, and the dynamic modulus of elasticity were measured. The permeability, the porosity and mechanical strength at 28-day age were measured. The flexural/compressive strength was measured after 90 wet-dry cycles. And then all the specimens were cut into cubes to take the measure of compressive strength. Based on the experiments, feasibility of various parameters, such permeability, relative dynamic modulus of elasticity, ultrasonic velocity and relative flexural/compressive strength, were investigated to evaluate the concrete deterioration. The results indicate that there is a close relationship between the deterioration by sulfate attack and concrete permeability, so the reduction of permeability is effective in promoting the resistance. The index of the resistance expressed by the dynamic modulus of elasticity ratio is comparable to that expressed by the relative flexural strength. A novel method was suggested in evaluating concrete by sulfate attack, namely, combined with some mechanical tests, the parameter of relative dynamic modulus of elasticity can be used to evaluate the deterioration; the permeability denoted as the amount of transporting charges within 6 hours can be used to evaluate the properties to sulfate attack.


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