scholarly journals Compressive Strength Properties of Geopolymers from Pond Ash and Possibility of Utilization as Synthetic Basalt

2019 ◽  
Vol 56 (4) ◽  
pp. 365-373
Author(s):  
Byoungkwan Kim ◽  
Bokyeong Lee ◽  
Chul-Min Chon ◽  
Sujeong Lee
Keyword(s):  
Compressive Strength ◽  
Strength Properties ◽  
Pond Ash

Strength Properties of Activated Hwangtoh Mortars

2010 ◽  
Vol 168-170 ◽  
pp. 709-715
Author(s):  
Dongsik Oh ◽  
Doheom Song ◽  
Seongseok Go
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Building Materials ◽  
Strength Properties ◽  
Mixing Conditions ◽  
Substitution Ratio ◽  
Pozzolanic Properties ◽  
The Relationship ◽  
Furnace Slag

Hwangtoh (loess) has pozzolanic properties that mean it can be used as a cement admixture when activated at high temperatures, and that it can be used in combination with building materials such as fly ash or blast furnace slag. This study aimed to analyze the relationship between the compressive strength and the brick bond strength of various mortars containing hwangtoh, and also to find the optimum mixing conditions for the use of hwangtoh. It was found that the mortars’ strength properties are significantly influenced by the water/cement ratio W/C and the activated hwangtoh substitution ratio. We recommend the following materials and mixing conditions: W/C 60%, a cement substitution ratio of activated hwangtoh of 20 ~ 25%, and the addition of 10% blast furnace slag to improve the compressive strength of such mortars.

scholarly journals Impact of Elevated Temperatures on Strength Properties and Microstructure of Calcium Sulfoaluminate Paste

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6751
Author(s):  
Konrad A. Sodol ◽  
Łukasz Kaczmarek ◽  
Jacek Szer ◽  
Sebastian Miszczak ◽  
Mariusz Stegliński
Keyword(s):  
Compressive Strength ◽  
Building Materials ◽  
Elevated Temperatures ◽  
Cooling System ◽  
Base Material ◽  
Visual Assessment ◽  
Strength Properties ◽  
Strength Parameters ◽  
Calcium Sulfoaluminate ◽  
Wide Range

This article is motivated by civil fire safety. Fire-prevention engineering demands a wide range of information about building materials including alternative cements, for instance CSA-cement. Because of exposure of the cement-base material to a high temperature, its strength properties deteriorate due to dehydration connected with phase and microstructure changes. Previous research indicated that the main endothermic reaction of CSA-based composite, dehydration of ettringite, might be used as a cooling system for a metal structure during fire-load. This article examines visual assessment, microstructure, density, as well as flexural and compressive strength parameters of CSA-based composite after isothermal heating at temperatures from 23 °C to 800 °C. The results of SEM/EDS investigations showed that the calcium sulfoaluminate paste may start partially re-sintering above 600 °C. Mechanical tests revealed significant reduction of strength parameters but residual compressive strength was maintained in the whole temperature range e.g., 8 MPa at 800 °C. Additionally, visual assessment of the specimens indicated that it might be possible to predict the material temperature heating based on the specific surface color. These findings add to the evidence of general knowledge about CSA hydrates.

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

scholarly journals Assessment of Workability and Compressive Strength of Rice Husk Ash-Blended Palm Kernel Shell Concrete

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
K. O. Oriola
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Construction Materials ◽  
Palm Kernel ◽  
Lightweight Aggregate ◽  
Strength Properties ◽  
Lightweight Aggregate Concrete ◽  
Palm Kernel Shell ◽  
Compressive Strength Of Concrete

The evaluation of agro-industrial by-products as alternative construction materials is becoming more significant as the demand for environmentally friendly construction materials increases. In this study, the workability and compressive strength of concrete produced by combining Palm Kernel Shell (PKS) and Rice Husk Ash (RHA) was investigated. Concrete mixes using a fixed content of 15% RHA as replacement for cement and 20, 40, 60, 80 and 100% PKS as replacement for crushed granite by volume with the mix ratios of 1:1½:3, 1:2:4 and 1:3:6 were produced. The water-to-cement ratios of 0.5, 0.6 and 0.7 were used for the respective mix ratios. Concrete without PKS and RHA served as control mix. The fresh concrete workability was evaluated through slump test. The concrete hardened properties determined were the density and compressive strength. The results indicated that the workability and density of PKSC were lower than control concrete, and they decreased as the PKS content in each mix ratio was increased. The compressive strength of concrete at 90 days decreased from 27.8-13.1 N/mm2, 23.8-8.9 N/mm2and 20.6-7.6 for 1:1½:3, 1:2:4 and 1:3:6, respectively as the substitution level of PKS increased from 0-100%. However, the compressive strength of concrete increased with curing age and the gain in strength of concrete containing RHA and PKSC were higher than the control at the later age. The concrete containing 15% RHA with up to 40% PKS for 1:1½:3 and 20% PKS for 1:2:4 mix ratios satisfied the minimum strength requirements for structural lightweight aggregate concrete (SLWAC) stipulated by the relevant standards. It can be concluded that the addition of 15% RHA is effective in improving the strength properties of PKSC for eco-friendly SLWAC production..

scholarly journals Experimental Researchon Flow and Strength Properties of Blended Fibre Reinforced Self Compacting Concrete

2019 ◽  
Vol 8 (6S4) ◽  
pp. 151-155
Keyword(s):  
Compressive Strength ◽  
Aspect Ratio ◽  
Considerable Increase ◽  
Mechanical Vibration ◽  
Strength Properties ◽  
Single Fiber ◽  
Moderate Increase ◽  
Fiber Reinforced ◽  
Self Compacting Concrete ◽  
Split Tensile Strength

Self compacting concrete achieves compaction by itself without using mechanical vibration techniques. Addition of fibers to SCC results in increased performance mainly in flexure, and also in compressive strength. In this study both the flow and strength properties of single Fiber and blended fiber reinforced self compacting concrete are examined in comparison with control self compacting concrete. crimpled steel fibers having size of 0.45mm diameter x 12.5mm length (aspect ratio 27.7) and 0.45mm diameter x 20 mm length (aspect ratio 44.44) are used in the SCC mix at various percentages by weight of cement i.e. 0%, 2%, 4% and 6%. From the obtained results it can be seen that there is aadverse affect on flow properties. There is a moderate increase in the compressive strength, split tensile strength and considerable increase in the flexural strength of the self compacting concrete using the blended fibers at different percentages i.e. at 2% and 4%, when compared to the single fiber reinforced self compacting concrete.

Influence of the Method of Polymerization of Composite Material for Teeth Crown Fillings on its Strength Properties

2015 ◽  
Vol 240 ◽  
pp. 168-173
Author(s):  
Grzegorz Milewski ◽  
Tomasz Majewski
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Composite Material ◽  
Modulus Of Elasticity ◽  
Strength Properties ◽  
Dental Practice ◽  
Polymerization Shrinkage ◽  
Filling Materials

Polymerization shrinkage of composite filling materials still becomes one of the most important features which decreases strength properties of reconstructed teeth crowns. From among various methods to reduce that disadvantageous phenomenon which are used in a dental practice sandwich filling processing of crown cavity seems to be the most effective one. The paper presents the results of the strength examination of the influence of the different ways of layered polymerization processing on the mechanical properties of modern hybrid micro composite material with regards to the following quantities: compressive strength, strain to fracture, modulus of elasticity and work to fracture.

Suitability of Cordia millenii Ash Blended Cement in Concrete Production

2016 ◽  
Vol 22 ◽  
pp. 59-67 ◽  
Author(s):  
Olusola Emmanuel Babalola ◽  
Paul O. Awoyera
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Blended Cement ◽  
Cementitious Materials ◽  
Strength Properties ◽  
Supplementary Cementitious Materials ◽  
Sieve Analysis ◽  
Concrete Production ◽  
Alternative Materials ◽  
Concrete Control

Supplementary cementitious materials are most needed to enhance a sustainable development in poor communities. It is pertinent to investigate the suitability of such alternative materials for construction. The present study evaluates the strength characteristics of concrete made with varied proportion of Cordia millenii ash blended with Portland cement. Chemical composition of Cordia millenii and the setting time when blended with cement was determined. Other laboratory tests performed on Cordia millenii blended cement include: sieve analysis and specific gravity. Five replacement percentages of Cordia millenii (5%, 10%, 15%, and 20%) were blended with cement in concrete. Control specimens were also produced with only cement. Tests to determine the workability, air entrained, bulk density and compressive strength properties of the concrete were also conducted. Results obtained revealed that optimum Cordia millenii mix is 10%, which yielded the highest density and compressive strength in the concrete.

scholarly journals The analysis of influence of polymer admixtures on properties of lightweight concrete

2019 ◽  
Vol 252 ◽  
pp. 08007 ◽  
Author(s):  
Jacek Góra ◽  
Danuta Barnat-Hunek ◽  
Paweł Wlaź ◽  
Monika Garbacz
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Statistical Analysis ◽  
Lightweight Concrete ◽  
Strength Properties ◽  
Freezing And Thawing ◽  
Factors Of Influence ◽  
Freezing And Thawing Cycles ◽  
Acetate Copolymer

The article presents the results of testing physical and strength properties of concrete with the addition of lightweight perlite in the amount of 10 and 20%. The additive was introduced by volume substituting a part of the sand. In addition, the effect of using siloxane admixtures and a vinyl acetate copolymer with different degree of dosing, as well as applied simultaneously, were analysed. The tests were carried out in the field of bulk density and proper density, determination of tightness and porosity, compressive strength and tensile strength after 28 days of maturation. In terms of durability of concrete, absorption and resistance of concretes to the freeze-up effects after 100 freezing and thawing cycles were tested. The results of the study were subjected to statistical analysis using the analysis of variance. The analysed factors of influence were the amount of perlite addition, as well as the type and amount of the added admixture

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