scholarly journals A Study on Initial Setting and Modulus of Elasticity of AAM Mortar Mixed with CSA Expansive Additive Using Ultrasonic Pulse Velocity

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4432
Author(s):  
Gum-Sung Ryu ◽  
Sung Choi ◽  
Kyung-Taek Koh ◽  
Gi-Hong Ahn ◽  
Hyeong-Yeol Kim ◽  
...  

This study investigated the hardening process of alkali-activated material (AAM) mortar using calcium sulfoalumiante (CSA) expansive additive (CSA EA), which accelerates the initial reactivity of AAMs, and subsequent changes in ultrasonic pulse velocity (UPV). After the AAM mortar was mixed with three different contents of CSA EA, the setting and modulus of elasticity of the mortar at one day of age, which represent curing steps, were measured. In addition, UPV was used to analyze each curing step. The initial and final setting times of the AAM mortar could be predicted by analyzing the UPV results measured for 14 h. In addition, the dynamic modulus of elasticity calculated using the UPV results for 24 h showed a tendency similar to that of the static modulus of elasticity. The test results showed that the use of CSA EA accelerated the setting of the AAM mortar and increased the modulus of elasticity, and these results could be inferred using UPV. The proposed measurement method can be effective in evaluating the properties of a material that accelerates the initial reactivity.

Author(s):  
Amanda Purwanto ◽  
Abdul Ro’uf

Modulus of elasticity of concrete usually measured by Destructive Testing which is not considered as an effective way, because It will destroy the concrete. Ultrasonic Pulse Velocity can be a solution to measure value of modulus of elasticity without destructing it. The concept of the system is to look for velocity of wave, then put the value into modulus elasticity formula.UPV system will transmit ultrasonic wave through concrete. HC-SR04 used for generating 40 kHz wave, increasing voltage of wave on receiver, and calculating time travel. The voltage of wave sent by HC-SR04 is only about 10 volt, so that power and voltage of wave has to be amplified. Piezoelectric is used as a transducer which can converts electrical to mechanical energy.  The results of this research shows that error value on wave velocity measurement have an average value for about 18,2% compared to result of UPV Pundit. Static modulus of elasticity from compressive test is compared to value of dynamic modulus of elasticity that is obtained by UPV system with HC-SR04. Ratio between two values is about 45% - 249%.


2020 ◽  
Vol 310 ◽  
pp. 00029
Author(s):  
Dalibor Kocab ◽  
Romana Halamová ◽  
Barbara Kucharczyková

The paper deals with the influence of the composition of cementitious materials on the development of their modulus of elasticity in the early stage of ageing. The primary goal of the paper is to determine the static modulus of elasticity of cement mortars almost from the beginning of their setting. Four cement mortars were produced for the experiment. They differed only in the water/cement ratio and in the amount of plasticizer. All mortars were subjected to continuous measurement of the dynamic modulus of elasticity for 24 hours from the moment of their pouring into the moulds. The measurement involved the ultrasonic pulse velocity method. In addition, the static modulus of elasticity was determined at the mortar age of 24 hours. The results are presented in table and graphical forms.


2018 ◽  
Vol 272 ◽  
pp. 28-33
Author(s):  
Dalibor Kocáb ◽  
Vlastimil Bílek Jr. ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Barbara Kucharczyková ◽  
...  

This article deals with an experimental determination of the static modulus of elasticity in compression on fine-grained composites based on alkali-activated slag. This experiment included an alkali-activated composite without a shrinkage-reducing admixture and the same composite with a shrinkage-reducing admixture. The test specimens were subjected to testing of the dynamic modulus of elasticity using the ultrasonic pulse velocity test and the resonance method as well as of the static modulus of elasticity in compression. The static modulus of elasticity test was accompanied by the measurement of the acoustic activity of the material using the acoustic emission method, whose advantages is the possibility to detect early formation and propagation of cracks in the internal structure of the material. The output of the described experiment is a detailed evaluation of the differences in the behaviour of the tested alkali-activated composites based on the observed values of the modulus of elasticity and the recorded acoustic activity of the material during loading.


2018 ◽  
Vol 162 ◽  
pp. 02015
Author(s):  
Ghalib Habeeb ◽  
Zahraa Hashim

The main aim of this research is to evaluate the performance of Nano silica self-compacting concrete which is subjected to severe saline conditions that contain sulfates and chlorides at concentrations similar to those existing in the soils and ground water of the middle and southern parts of Iraq. For this purpose, ordinary and sulfate resistant Portland cement without and with 3% Nano silica addition by weight of cementitious materials were used. Splitting tensile strength, flexural strength, static modulus of elasticity and ultrasonic pulse velocity were investigated for all exposure conditions and all types of mixes of self-compacting concrete at ages of 28, 60, 90, 120 and 180 days. Test results revealed that the inclusion of Nano Silica in concrete mixes improved clearly the mechanical properties of self-compacting concrete compared with reference concrete.


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.


2018 ◽  
Vol 276 ◽  
pp. 35-40
Author(s):  
Romana Halamová ◽  
Dalibor Kocáb ◽  
Barbara Kucharczyková ◽  
Petr Daněk ◽  
Petr Misák

This paper deals with the possibilities of experimental determination of the dynamic and static modulus of elasticity of fine-grained cement composites in the early stage of setting and hardening - up to 72 hours. Several cement pastes and cement mortars were produced for the purpose of this experiment. The measurement of the modulus of elasticity on the manufactured cement-based composites was carried out in the first 24 hours, each time only by the ultrasonic pulse velocity test using the innovative Vikasonic instrument. In the following 48 hours, the resonance method and the static load test were employed. The results of the pilot measurement and particularly the assessment of the possibilities of determination of the moduli of elasticity are presented in this paper.


2018 ◽  
Vol 760 ◽  
pp. 266-271
Author(s):  
Dalibor Kocáb ◽  
Libor Topolář ◽  
Vlastimil Bílek Jr. ◽  
Barbara Kucharczyková ◽  
Michaela Hoduláková ◽  
...  

This paper describes an experiment focused on monitoring the development of the modulus of elasticity and the compressive strength of composites that are based on alkali‑activated slag (AAS) during the first 28 days of ageing. The test specimens were tested at the age of 3 and 28 days using two non-destructive methods (ultrasonic pulse and resonance methods) to determine the value of the dynamic modulus of elasticity. Subsequently, the same specimens were used to determine the static modulus of elasticity using compressive stress test, during which the behaviour of the composite was monitored by equipment for recording the acoustic emission in the material. The result of the experiment is the evaluation of the behaviour of the AAS composite in regard to the development of its modulus of elasticity and compressive strength, as well as in regard to the acoustic emission method during loading.


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