scholarly journals Effect of Main Factors on Fracture Mode of Mortar, A Graphical Study

2017 ◽  
Vol 3 (10) ◽  
pp. 897 ◽  
Author(s):  
Sahar Mahdinia ◽  
Hamid Eskandari-Naddaf ◽  
Rasoul Shadnia
Keyword(s):  
Cement Paste ◽  
Fracture Mode ◽  
Cement Mortar ◽  
Fine Aggregate ◽  
Stress Strain ◽  
Related Factors ◽  
Fracture Angle ◽  
Concrete Properties ◽  
Main Factors ◽  
Cement Strength

One of the most effective ways to identify the concrete properties is to understand further about the cement mortar, which is a mixture of cement paste and fine aggregate. In order to identify the behavior of cement mortar, all required materials including cement, fine aggregate, water as well as the different ratios of each material should beinvestigated. The main objective of this research is to study the effectiveness of main parameters of mortar on the fracture mode and related factors. Specifically 26 mixing designs of flexural mortar with three cement strength classes (32.5, 42.5 and 52.5 MPa), three water to cement (W/C) ratios (0.25, 0.3 and 0.35) and three sand to cement (S/C) ratios (2.5, 2.75 and 3) were first prepared. The prepared samples were then tested using a stress-strain apparatus. Some pictures were finally taken from the fracture surfaces to investigate the mode and angle of fractures. The results indicated that any change in the main parameters of mortar changes the fracture mode and the fracture angle.

scholarly journals Preparation of Electric- and Magnetic-Activated Water and Its Influence on the Workability and Mechanical Properties of Cement Mortar

2021 ◽  
Vol 13 (8) ◽  
pp. 4546
Author(s):  
Kaiyue Zhao ◽  
Peng Zhang ◽  
Bing Wang ◽  
Yupeng Tian ◽  
Shanbin Xue ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Paste ◽  
Cement Mortar ◽  
Environmental Issues ◽  
Chemical Admixtures ◽  
Untreated Water ◽  
Alternating Voltage

Cement-based materials prepared with activated water induced by a magnetic field or electric field represent a possible solution to environmental issues caused by the worldwide utilization of chemical admixtures. In this contribution, electric- and magnetic-activated water have been produced. The workability and mechanical properties of cement mortar prepared with this activated water have been investigated. The results indicate that the pH and absorbance (Abs) values of the water varied as the electric and magnetic field changed, and their values increased significantly, exhibiting improved activity compared with that of the untreated water. In addition, activated water still retains activity within 30 min of the resting time. The fluidity of the cement paste prepared with electric-activated water was significantly larger than that of the untreated paste. However, the level of improvement differed with the worst performance resulting from cement paste prepared with alternating voltage activated water. In terms of mechanical properties, both compressive strength and flexural strength obtained its maximum values at 280 mT with two processing cycles. The compressive strength increased 26% as the curing time increased from 7 days to 28 days and flexural strength increased by 31%. In addition, through the introduction of magnetic-activated water into cement mortar, the mechanical strength can be maintained without losing its workability when the amount of cement is reduced.

scholarly journals Performance Evaluation of Soft Computing for Modeling the Strength Properties of Waste Substitute Green Concrete

2021 ◽  
Vol 13 (5) ◽  
pp. 2867
Author(s):  
Muhammad Izhar Shah ◽  
Muhammad Nasir Amin ◽  
Kaffayatullah Khan ◽  
Muhammad Sohaib Khan Niazi ◽  
Fahid Aslam ◽  
...  
Keyword(s):  
Predictive Models ◽  
Parametric Study ◽  
Cross Validation ◽  
Strength Properties ◽  
Fine Aggregate ◽  
Agricultural Industry ◽  
Green Concrete ◽  
Concrete Properties ◽  
Water To Cement Ratio ◽  
Sugarcane Bagasse Ash

The waste disposal crisis and development of various types of concrete simulated by the construction industry has encouraged further research to safely utilize the wastes and develop accurate predictive models for estimation of concrete properties. In the present study, sugarcane bagasse ash (SCBA), a by-product from the agricultural industry, was processed and used in the production of green concrete. An advanced variant of machine learning, i.e., multi expression programming (MEP), was then used to develop predictive models for modeling the mechanical properties of SCBA substitute concrete. The most significant parameters, i.e., water-to-cement ratio, SCBA replacement percentage, amount of cement, and quantity of coarse and fine aggregate, were used as modeling inputs. The MEP models were developed and trained by the data acquired from the literature; furthermore, the modeling outcome was validated through laboratory obtained results. The accuracy of the models was then assessed by statistical criteria. The results revealed a good approximation capacity of the trained MEP models with correlation coefficient above 0.9 and root means squared error (RMSE) value below 3.5 MPa. The results of cross-validation confirmed a generalized outcome and the resolved modeling overfitting. The parametric study has reflected the effect of inputs in the modeling process. Hence, the MEP-based modeling followed by validation with laboratory results, cross-validation, and parametric study could be an effective approach for accurate modeling of the concrete properties.

Hardening Cement Conglomerates by Mining Industries Waste

2021 ◽  
Vol 316 ◽  
pp. 1061-1066
Author(s):  
Lilia V. Ilina ◽  
Irina N. Mukhina ◽  
Mariya M. Semenova
Keyword(s):  
Cement Paste ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Period Increase ◽  
Complex Additive ◽  
Nonlinear Mathematical Models ◽  
Study Results ◽  
Cement Strength ◽  
Heat And Moisture ◽  
Mineral Additives

About 3.5 billion tons of mining waste is generated annually in Russia. The task of their utilization is urgent in connection with the accumulation of large-tonnage waste of simultaneously mined rocks, enrichment waste and crushing screenings. The problem can be solved by using these wastes as mineral additives to artificial cement-based conglomerates. According to the study results it was found, that the compressive strength of hardened cement paste increased during all hardening periods, when finely dispersed mining wastes were introduced. In the early stages of hardening, limestone had a predominant effect. Introduction of diopside led to the greatest hardening together with the hardening period increase. Linear and nonlinear mathematical models, describing the dependence of cement strength on the type and amount of mineral additives, were constructed. The highest strength values of hardened cement paste, both after hardening under normal conditions for 28 days, and after heat and moisture treatment could be achieved with 7% dispersed diopside. At the same time, the hardening effect (increase in the strength of cement by 35–40%) was retained when 1/3 of the diopside in the complex additive was replaced by dispersed limestone. An increase in the content of limestone in the complex additive composition over 1/3 was impractical.

Reuse potential of stabilized excavation soil as fine aggregate in cement mortar

2018 ◽  
Vol 192 ◽  
pp. 141-152 ◽  
Author(s):  
P. Priyadharshini ◽  
K. Ramamurthy ◽  
R.G. Robinson
Keyword(s):  
Cement Mortar ◽  
Fine Aggregate

scholarly journals THERMAL COMFORT INVESTIGATION ON HOLY MOSQUE IN BANDUNG Case Study : Lautze 2 Mosque Bandung

2020 ◽  
Vol 2 (1) ◽  
pp. 82
Author(s):  
Agung Prabowo
Keyword(s):  
Thermal Comfort ◽  
Quantitative Research ◽  
Thermal Environment ◽  
Tropical Climate ◽  
Air Humidity ◽  
Air Velocity ◽  
Related Factors ◽  
Climate Conditions ◽  
Comfort Index ◽  
Main Factors

Abstract -Thermal comfort is a state of mind that expresses satisfaction with the thermal environment. There are two main categories in the effort to obtain a comfort index; empirical and analytical. Empirical is based on social surveys, while analysis is based on the physics principle of heat flow.Bandung city is one of the historical cities in Indonesia which has many historical heritage buidings. One of them which is commonly known as colonial buildings in Bandung is Lautze 2 Mosque, located at Tamblong Street in the city center of Bandung. This research was conducted to analyze the thermal comfort in the Lautze 2 Mosque Bandung. The analytical method used in this study is a quantitative research method by measuring the main factors namely air temperature, air humidity and air velocity. The main factors become obstacles to get thermal comfort data at the Lautze 2 Mosque Bandung is the location of buildings located in areas with tropical climate conditions with high air temperatures, high air humidity, and low air velocitys.The research conclude that thermal comfort in the Lautze 2 Mosque Bandung building can be categorized as uncomfortable, it can be seen from the measurement results of related factors, namely the temperature and humidity that exceeds the comfort limit and the low air velocity in the building becomes an obstacle to obtain thermal comfort. Keywords: colonial buildings, mosque, thermal comfort, tropical climate.

Chemo-Micro-Dilatation Modeling of Carbonation Shrinkage Phenomenon of the Porous Mortars

2011 ◽  
Vol 261-263 ◽  
pp. 680-684 ◽  
Author(s):  
T. X. Dinh ◽  
J. Jeong ◽  
H. Ramézani ◽  
Z. Q. Feng
Keyword(s):  
Cement Paste ◽  
Cement Mortar ◽  
Ph Value ◽  
Empirical Method ◽  
Micro Structure ◽  
Unknown Parameters ◽  
Scientific Goal ◽  
Different Types ◽  
Semi Empirical ◽  
Carbonation Shrinkage

In this paper, we investigate the CO2 carbonation on porous materials such as the cement paste mortar. Our scientific goal is to model the CO2 carbonation effect on the porous cement mortar by the micro-dilatation theory and to determine the chemo-mechanical stress development due to the chemical reactions. In fact, this phenomenon will modify not only the pH value of the cement paste but also the micro-structure due to collapsing pore-network. Based upon the micro-dilatation theory originally proposed by Cowin and Nunziato, four unknown parameters related to the micro-structure will be determined for the cement mortar using the semi-empirical method and numerical modeling. The experimental carbonation tests on two different types of cement paste (CEMI and CEMIII) have been realized to capture carbonated affected zones and to measure their shrinkage deformations.

The Mechanism of Mineral Admixture in Cement Hydration

2012 ◽  
Vol 450-451 ◽  
pp. 1528-1531
Author(s):  
Mei Li Zhao
Keyword(s):  
Cement Paste ◽  
High Performance ◽  
Cement Hydration ◽  
High Performance Concrete ◽  
Cement Mortar ◽  
Sem Analysis ◽  
Mineral Admixture ◽  
Hydration Mechanism ◽  
Curing Period ◽  
Durability Performance

The mineral admixture is one of the indispensable materials for ordinary high-performance concrete. In this paper, the pure cement paste and cement paste replacing by mineral admixture were tested by cement mortar. The SEM analysis of pure cement paste and mineral admixture paste after curing period of 7 days and 28 days.From the picture of SEM after the period of 7 days and 28 days,the cement hydration mechanism was suspected.It could be used for explanating the physical performance and durability performance of the high perfromance concrete with mineral admixture.

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