scholarly journals Study some mechanical properties of self-compacting concrete with nano silica under severe saline environment conditions

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.

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.


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%.


Author(s):  
Darmono Darmono ◽  
Maris Setyo Nugroho ◽  
Slamet Widodo ◽  
Faqih Ma’arif

ABSTRAKPenelitian bertujuan untuk mengetahui mechanical properties material kayu Bangunan Cagar Budaya dengan non-destructive test. Penelitian ini menggunakan metode pengujian lansung dilapang menggunakan Ultrasonic Pulse Velocity (UPV). Terdapat dua variable yang digunakan yaitu kolom cacat dan kolom utuh untuk mengetahui perbedaan nilai cepat rambat gelombang. Jumlah sampel yang digunakan sebanyak enam buah dengan pengambilan data masing-masing sampel sebanyak lima kali. Hasil pengujian menunjukkan bahwa nilai kadar air dan berat jenis kayu sebesar 15,03% dan 0,62. Sedangkan hasil pengujian UPV pada kolom cacat dan utuh diperoleh cepat rambat gelombang sebesar 0,71 km/s dan 1,21 km/s. Berdasarkan hasil analisis menunjukkan bahwa nilai MOEd pada kolom utuh sebesar 9.374,37 MPa, sedangkan MOEd pada kolom cacat sebesar 3.240,62 MPa. Kata kunci: mechanical properties kayu, bangunan cagar budaya, ultrasonic pulse velocity ABSTRACTThis study aims to determine the mechanical properties of the wood material for the Cultural Heritage Building with a non-destructive test. This study used a direct field testing method using Ultrasonic Pulse Velocity (UPV). There are two variables used, namely the defective column and the solid column to determine the difference in the value of the fast propagation of the waves. The number of samples used was six with data collection for each sample five times. The test results showed that the moisture content and density of wood were 15.03% and 0.62. While the UPV test results on defective and solid columns obtained wave propagation velocity of 0.71 km / s and 1.21 km / s. Based on the analysis result, it shows that the MOEd value in the whole column is 9,374.37 MPa, while the MOEd in the defective column is 3,240.62 MPa. Keywords: mechanical properties of wood, cultural heritage buildings, ultrasonic pulse velocity


2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gaurav Sancheti ◽  
Vikram Singh Kashyap ◽  
Jitendra Singh Yadav

Purpose The purpose of this study is to perform comprehensive investigation to assess the mechanical properties of nano-modified ternary cement concrete blend. Nano silica (NS) (1%, 2% and 3%) and waste marble dust powder (MD) (5%, 10% and 15%) was incorporated as a fractional substitution of cement in the concrete matrix. Design/methodology/approach In this experimental study, 10 cementitious blends were prepared and tested for compressive strength, flexural strength, splitting tensile strength and static modulus of elasticity. The microstructural characteristics of these blends were also explored using a scanning electron microscope along with energy dispersive spectroscopy and X-ray reflection. Findings The results indicate an enhancement in mechanical properties and refinement in pore structure due to improved pozzolanic activities of NS and the filling effect of MD. Originality/value To the best of the authors’ knowledge, no study has reported the mechanical and microstructural behavior of concrete containing marble and NS.


There is a substantial curiosity in academia, the investment community and among manufacturers about the exhilarating opportunities offered by nano materials. Although a lot of applications for nanotechnology remain hypothetical, construction is one area where numerous ‘here and now’ applications have already emerged. While existing use is restricted, the market is likely to approach more than 500 million dollars within ten years. Concrete is most likely exceptional in the construction field, that it is the distinct material exclusive to business and hence, is the recipient of a reasonable quantity of research and development capital from the construction industry. SiO2 (Silica) usually is an integral part of concrete in the normal mix. On the other hand, one of the innovations made by the study of concrete at nano scale level is that particle stuffing in concrete can be enhanced by means of adding nano silica (NS), which results in the densification of the micro and nano structure of cementitious composite resulting in enhanced mechanical properties. In this research paper, the result of a thorough investigational analysis on the utilization of NS in addition to cement so that the strength and quality of concrete can improve has been achieved. The effect of various proportions of NS in concrete has been premeditated to evaluate the properties of NS based hardened concrete according to the standard concrete. The obtained outcomes after testing indicate that the addition of NS together with concrete has improved the mechanical behavior of concrete. The NS blended high strength concrete (HSC) shows a better compressive strength (CS) of 66.00 N/mm2 (MPa) after standard twenty eight days, which is an exceptional development over standard concrete. Each and every mixture containing NS in various proportions gave enhanced outcomes in comparison with the standard predictable concrete. RH (Rebound Hammer), UPV (Ultrasonic Pulse Velocity), SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope) examinations further authenticate the above results.


2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Fatih Özcan ◽  
Halil Kaymak

In this work, utilization of metakaolin (MK) and calcite (C), working reversely in workability aspect, as mineral admixture in self-compacting concrete (SCC), was investigated. MK and C replaced cement in mass basis at various replacement ratios, separately and together. In total, 19 different SCCs were produced. Binder content and water to binder ratio were selected as 500 kg/m3 and 0.4, respectively. Workability tests including slump flow, T50, L-box, and V-funnel tests were performed. Consistency and setting times of binder paste were measured. While replacement of MK with cement increased the amount of plasticiser requirement, calcite worked reversely and decreased it. Reverse influence of MK and C on plasticiser requirement of SCC made possible to produce SCC at total 45% replacement ratio of MK and C together. Samples of SCC were cured in water at 20°C temperature. Compressive strengths of SCC samples were measured up to six months to evaluate the influence of MK and C, separately and together. Ultrasonic pulse velocity, abrasion, and capillary water absorption values of samples were determined at specified age. MK inclusion in concrete reduces workability, while C inclusion increases it. C and MK inclusion together remedied workability of concrete and enabled to produce SCC with high volume of admixtures. Furthermore, C incorporation increased one-day compressive strength, while MK incorporation reduced it in comparison with control concrete. In long term, C inclusion reduced compressive strength; however, MK inclusion increased it. C inclusion remedied one-day strength of concrete when it was used together with MK. MK inclusion remedied long-term compressive strength when it was used together with C and enabled to produce high-strength SCC with high volume of admixtures. SCC containing MK and C together showed better durability-related property.


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