scholarly journals Evaluation of Strengths from Cement Hydration and Slag Reaction of Mortars Containing High Volume of Ground River Sand and GGBF Slag

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Punnaman Norrarat ◽  
Weerachart Tangchirapat ◽  
Smith Songpiriyakij ◽  
Chai Jaturapitakkul
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Cement Hydration ◽  
High Volume ◽  
Inert Material ◽  
Early Age ◽  
Particle Sizes ◽  
River Sand ◽  
Reactive Material ◽  
Median Particle

This paper investigates the cement hydration, and the slag reaction contributes to the compressive strengths of mortars mixed with ground river sand (GRS) and ground-granulated blast furnace (GGBF) slag with different particle sizes. GRS (inert material) and GGBF slag (reactive material) were ground separately until the median particle sizes of 32 ± 1, 18 ± 1, and 5 ± 1 micron and used to replace Portland cement (PC) in large amount (40–60%) by weight of the binder. The results showed that, at the early age, the compressive strength obtained from the cement hydration was higher than that obtained from the slag reaction. The results of compressive strength also indicated that the GGBF slag content and particle size play important roles in the slag reaction at the later ages, whereas cement hydration is more prominent at the early ages. Although the results could be expected from the use of GGBF slag to replace PC in mortar or concrete, this study had presented the values of the compressive strength along with ages and the finenesses of GGBF slag that contributed from cement hydration and from GGBF slag reaction.

scholarly journals Particle Size Effect of Oyster Shell on Mortar: Experimental Investigation and Modeling

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6813
Author(s):  
Yingdi Liao ◽  
Hongyi Shi ◽  
Shimin Zhang ◽  
Bo Da ◽  
Da Chen
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Particle Sizes ◽  
River Sand ◽  
Standard Requirement ◽  
Slump Flow ◽  
Curing Age

In order to solve the problem of lack of natural river sand, crushed waste oyster shells (WOS) were used to replace river sand. By replacing 20% river sand, WOS mortar with different particle sizes of WOS were made for the experiment. Through experimental observation, the initial slump and slump flow loss rate were studied. The effects of different particle sizes and curing times on the compressive strength, flexural strength, static elastic modulus, and dry shrinkage of WOS mortar were analyzed. The relationship formulas between the compressive strength, flexural strength, particle size, and curing age were proposed. The results showed that the setting time and slump flow decreased with a decrease in the particle size of WOS. It was also found that the mortar with fine crushed WOS had high compressive strength, flexural strength, and static elastic modulus at both early and long-term curing age. A formula was proposed to describe the development of the compressive strength with the particle size of WOS and curing time, and the relations among these mechanical properties were discussed. Furthermore, drying shrinkage increased when WOS was used and could not satisfy the standard requirement of 0.075%. In contrast, the addition of fine WOS and double-dose sulfonated naphthalene-formaldehyde superplasticizer (SNF SP) reduced the shrinkage rate of the mortar by 8.35% and provided better workability and mechanical properties for mortar.

scholarly journals Experimental Analysis of the Mechanical Properties and Resistivity of Tectonic Coal Samples with Different Particle Sizes

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2303
Author(s):  
Congyu Zhong ◽  
Liwen Cao ◽  
Jishi Geng ◽  
Zhihao Jiang ◽  
Shuai Zhang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Coalbed Methane ◽  
Coal Sample ◽  
Fine Particles ◽  
Particle Sizes ◽  
Tectonic Coal

Because of its weak cementation and abundant pores and cracks, it is difficult to obtain suitable samples of tectonic coal to test its mechanical properties. Therefore, the research and development of coalbed methane drilling and mining technology are restricted. In this study, tectonic coal samples are remodeled with different particle sizes to test the mechanical parameters and loading resistivity. The research results show that the particle size and gradation of tectonic coal significantly impact its uniaxial compressive strength and elastic modulus and affect changes in resistivity. As the converted particle size increases, the uniaxial compressive strength and elastic modulus decrease first and then tend to remain unchanged. The strength of the single-particle gradation coal sample decreases from 0.867 to 0.433 MPa and the elastic modulus decreases from 59.28 to 41.63 MPa with increasing particle size. The change in resistivity of the coal sample increases with increasing particle size, and the degree of resistivity variation decreases during the coal sample failure stage. In composite-particle gradation, the proportion of fine particles in the tectonic coal sample increases from 33% to 80%. Its strength and elastic modulus increase from 0.996 to 1.31 MPa and 83.96 to 125.4 MPa, respectively, and the resistivity change degree decreases. The proportion of medium particles or coarse particles increases, and the sample strength, elastic modulus, and resistivity changes all decrease.

scholarly journals Effect of Morphologically Controlled Hematite Nanoparticles on the Properties of Fly Ash Blended Cement

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1003
Author(s):  
Pantharee Kongsat ◽  
Sakprayut Sinthupinyo ◽  
Edgar A. O’Rear ◽  
Thirawudh Pongprayoon
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Size Distribution ◽  
Cement Hydration ◽  
Blended Cement ◽  
Spherical Shape ◽  
Particle Sizes ◽  
Fe2o3 Nanoparticles ◽  
Structure And Properties ◽  
Hematite Nanoparticles

Several types of hematite nanoparticles (α-Fe2O3) have been investigated for their effects on the structure and properties of fly ash (FA) blended cement. All synthesized nanoparticles were found to be of spherical shape, but of different particle sizes ranging from 10 to 195 nm depending on the surfactant used in their preparation. The cement hydration with time showed 1.0% α-Fe2O3 nanoparticles are effective accelerators for FA blended cement. Moreover, adding α-Fe2O3 nanoparticles in FA blended cement enhanced the compressive strength and workability of cement. Nanoparticle size and size distribution were important for optimal filling of various size of pores within the cement structure.

scholarly journals Influence of Particle Size Distribution of High Calcium Fly Ash on HVFA Mortar Properties

2018 ◽  
Vol 20 (2) ◽  
pp. 51
Author(s):  
Antoni . ◽  
Hendra Surya Wibawa ◽  
Djwantoro Hardjito
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Setting Time ◽  
High Volume ◽  
High Volume Fly Ash ◽  
High Calcium ◽  
High Calcium Fly Ash

This study evaluates the effect of particle size distribution (PSD) of high calcium fly ash on high volume fly ash (HVFA) mortar characteristics. Four PSD variations of high calcium fly ash used were: unclassified fly ash and fly ash passing sieve No. 200, No. 325 and No. 400, respectively. The fly ash replacement ratio of the cementitious material ranged between 50-70%. The results show that with smaller fly ash particles size and higher levels of fly ash replacement, the workability of the mixture was increased with longer setting time. There was an increase in mortar compressive strength with finer fly ash particle size, compared to those with unclassified ones, with the highest strength was found at those with fly ash passing mesh No. 325. The increase was found due to better compactability of the mixture. Higher fly ash replacement reduced the mortar’s compressive strength, however, the rate was reduced when finer fly ash particles was used.

Influence of Powder Particle Size of Slurries on Mechanical Properties of Porous Hydroxyapatite Ceramics

2005 ◽  
Vol 284-286 ◽  
pp. 365-368 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Particle Sizes ◽  
Wet Milling ◽  
Median Particle Size ◽  
Powder Characteristics ◽  
Median Particle

The effect of different particle sizes on the flexural strength and microstructure of three different types of hydroxyapatite (HAp) powders was studied. The powder characteristics of laboratory synthesized HAp powder (Lab1 and Lab2) were obtained through a wet milling method, and the median particle size and the specific surface area of powders are different with the dryness period. The median particle sizes of Lab1 and Lab2 are 0.34 µm and 0.74 µm, and the specific surface areas of Lab1 and Lab2 are 38.01 m2/g and 19.77 m2/g. The commercial HAp had median particle size of 1.13 µm and specific surface area of 11.62m2/g. The different powder characteristics affected the slip characteristics, and the flexural strength and microstructure of the sintered porous HAp bodies are also different. The optimum value for the minimum viscosity in these present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were investigated. The flexural strengths of the porous HAp ceramics prepared by heating at 1200°C for 3 hrs in air were 17.59 MPa for Lab1 with a porosity of 60.48％, 10.51 MPa for Lab2 with a porosity of 57.75％, and 3.92 MPa for commercial HAp with a porosity of 79.37％.

Effects of Fly Ash Particle Sizes on the Compressive Strength and Fracture Toughness of High Performance Concrete

2011 ◽  
Vol 284-286 ◽  
pp. 984-988
Author(s):  
An Shun Cheng ◽  
Yue Lin Huang ◽  
Chung Ho Huang ◽  
Tsong Yen
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
Bending Test ◽  
Strength Development ◽  
Particle Sizes

The study aims to research the effect of the particle size of fly ash on the compressive strength and fracture toughness of high performance concrete (HPC). In all HPC mixtures, the water-to-binder ratio selected is 0.35; the cement replacement ratios includes 0%, 10% and 20%; the particle sizes of fly ash have three types of passing through sieves No. 175, No. 250 and No. 325. Three-point-bending test was adopted to measure the load-deflection relations and the maximum loads to determine the fracture energy (GF) and the critical stress intensity factor (KSIC). Test results show that adding fly ash in HPC apparently enhances the late age strengths of HPC either for replacement ratio of 10% or 20%, in which the concrete with 10% fly ash shows the higher effect. In addition, the smaller the particle size is the better the late age concrete strength will be. The HPC with the finer fly ash can have higher strength development and the values of GF and KSIC due to the facts of better filling effect and pozzolanic reaction. At late age, the GF and KSIC values of concrete with 10% fly ash are all higher than those with 20% fly ash.

scholarly journals Feasibility Tests on Concrete with Very-High-Volume Supplementary Cementitious Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Keun-Hyeok Yang ◽  
Yong-Su Jeon
Keyword(s):  
Compressive Strength ◽  
Weight Ratio ◽  
High Volume ◽  
Cementitious Materials ◽  
Positive Influence ◽  
Supplementary Cementitious Materials ◽  
Early Age ◽  
Freezing And Thawing ◽  
Strength And Durability ◽  
Very High

The objective of this study is to examine the compressive strength and durability of very high-volume SCM concrete. The prepared 36 concrete specimens were classified into two groups according to their designed 28-day compressive strength. For the high-volume SCM, the FA level was fixed at a weight ratio of 0.4 and the GGBS level varied between the weight ratio of 0.3 and 0.5, which resulted in 70–90% replacement of OPC. To enhance the compressive strength of very high-volume SCM concrete at an early age, the unit water content was controlled to be less than 150 kg/m3, and a specially modified polycarboxylate-based water-reducing agent was added. Test results showed that as SCM ratio (RSCM) increased, the strength gain ratio at an early age relative to the 28-day strength tended to decrease, whereas that at a long-term age increased up toRSCMof 0.8, beyond which it decreased. In addition, the beneficial effect of SCMs on the freezing-and-thawing and chloride resistances of the concrete decreased atRSCMof 0.9. Hence, it is recommended thatRSCMneeds to be restricted to less than 0.8–0.85 in order to obtain a consistent positive influence on the compressive strength and durability of SCM concrete.

scholarly journals A Study on the utilization of coffee grounds for particle board

2021 ◽  
Vol 10 (2) ◽  
pp. 48-52
Author(s):  
Cut Rizka Maulida ◽  
Mursal Mursal ◽  
Ismail Ismail
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Physical Properties ◽  
Epoxy Resin ◽  
Particle Sizes ◽  
Particle Board ◽  
Thickness Swelling ◽  
Coffee Grounds ◽  
Coffee Ground

Abstrak. Penelitian ini bertujuan untuk membuat papan partikel dengan menggunakan limbah ampas kopi dan resin epoksi sebagai perekat. Komposisi resin epoksi divariasikan yaitu 5, 10, 15 dan 20 vol.% untuk masing-masing partikel ampas kopi berukuran 20 dan 40 mesh. Papan partikel dibuat dengan teknik pressing dengan beban sebesar 9 ton selama 30 menit. Sifat mekanik yang diuji adalah MOE, MOR, dan kuat tekan. Sifat fisis papan partikel yang diuji adalah kerapatan dan pengembangan tebal. Hasil menunjukkan bahwa nilai MOE tertinggi yaitu 20,910 kgf/cm2 pada komposisi 95 vol.% ampas kopi dan 5 vol.% resin epoksi dengan ukuran ampas kopi 40 mesh. MOR tertinggi yaitu 167 kgf/cm2 pada ukuran partikel 40 mesh dengan komposisi ampas kopi 90 vol.% dan resin epoksi 10 vol.%. Nilai kuat tekan tertinggi diperoleh 220 kgf/cm2 pada 20 mesh, dengan komposisi 85 vol.% ampas kopi dan 15 vol.% resin epoksi. Kerapatan dan pengembangan tebal papan partikel yang tertinggi masing-masing adalah 1,16 g/cm3 dan 0,85%. Secara umum, sifat mekanis papan partikel ampas kopi tergantung pada komposisi dan ukuran partikel ampas kopi. Namun, sifat fisisnya tidak berubah secara signifikan untuk ukuran partikel dan komposisi yang berbeda. Papan partikel yang diperoleh dari penelitian ini memenuhi standar ANSI sehingga berpotensi untuk dijadikan sebagai papan partikel atau komposit. Abstract.. This study aims to make a particle board using coffee ground waste and epoxy resin as an adhesive. The composition of the epoxy resin was varied, namely 5, 10, 15 and 20 vol.% for 20 mesh and 40 mesh of coffee grounds particles. Particle board is made by pressing technique with a load of 9 tons for 30 minutes. The mechanical properties tested were MOE, MOR, and compressive strength. The physical properties of the particle board tested were density and thickness swelling. The results showed that the highest MOE particle board was 20.910 kgf/cm2 (95 vol.% coffee grounds:5 vol.% epoxy resin; 40 mesh). The highest MOR was 167 kgf/cm2 (90 vol.% coffee grounds:10 vol.% epoxy resin;40 mesh). The hihgest compressive strength values was 220 kgf/cm2 (85 vol.% coffee grounds:15 vol.% epoxy resin;20 mesh). The highest density and thickness expansion were 1.16 g/cm3 and 0.85%, respectively. In general, the mechanical properties of coffee grounds particleboard depend on the composition and particle size of coffee grounds. However, their physical properties do not change significantly for different particle sizes and compositions. The particle board obtained from this study meets the standard of ANSI. Thus, coffee grounds have the potential to be used as particle board or composite. Keywords particle board, coffee grounds, epoxy resin, mechanical properties, physical properties

Investigations on Degradable and Figuline Calcium Alkaline Phosphate Cements with Multimodal Particle Size Distribution

2011 ◽  
Vol 493-494 ◽  
pp. 355-360
Author(s):  
F. Dombrowski ◽  
R. Hoffmann ◽  
Ute Ploska ◽  
Heidi Marx ◽  
Georg Berger
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Setting Time ◽  
Volume Ratio ◽  
Particle Sizes ◽  
Powder Mixtures ◽  
Setting Reaction ◽  
Tap Density

The paper presented here deals with rheological and hardening properties during the setting reaction, and density and compressive strength after the final setting of a figuline composite consisting of Ca2KNa(PO4)2and 2wt% medium gel strength gelatin. Compared to the composite with monomodal particle size distribution (d50=7.18µm; span=3.9) and its properties during and after setting reaction, the goal of this work is to increase the resulting product compressive strength by mixing different particle sizes in order to obtain bi- and trimodal distributions. For the bimodal powder mixtures the ratio in diameter (dcourse/dsmall) was chosen with 7/1 and volume ratio dcourse/dsmallwas 70/30%. For the trimodal powder mixtures the ratio in diameter (dcourse/dmedium/dsmall) was chosen with 70/7/1 and volume ratio dcourse/dmedium/dsmallwas set to 44/28/28%.After establishing an adequate crushing and sieving process the tap density and powder density of each fraction was determined. Subsequently, the different particle sizes were mixed and the densities and the Hausner ratio were determined again. The mixtures show an increase in both densities especially the tap density increased significantly. Rheological investigations show that the graphs of storage and loss moduli of the multimodal powder mixtures respectively are similar. The characteristic setting times show a slight decrease compared with the monomodal composite but not significantly different data. When comparing the resulting compressive strength of cylindrical samples, which were stored direct after reaching the initial setting time under physiological conditions, the studies illustrated in all cases for the multimodal mixtures a significant increase in compressive strength and a higher density.

Strength Study of Concrete Made with Various Local Sands in Benin City, Nigeria

2007 ◽  
Vol 18-19 ◽  
pp. 21-26
Author(s):  
O.E. Alutu ◽  
B.K. Ifejika
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Design Method ◽  
Impurity Content ◽  
Sand Sample ◽  
River Sand ◽  
Benin City ◽  
Compressive Strength Of Concrete

The paper focuses on the effect which varying the type of sand used in concrete will have on the compressive strength of concrete and seeks to determine the suitability of each sand for use in concrete works. The sand samples used include Okhoro, Ikpoba, Ovia and Okhuahiaerosion sands and Ikpoba, Ovia and Okhuahia river sands. Particle size distribution of the sands was first determined and the result was used to design grades 20, 25, and 30 concretes to Department of Environment (DOE) mix design method. Twelve cubes were cast from one particular sand sample and three cubes were tested at 7, 14 and 28 days for each grade of concrete respectively .The result revealed that the sand samples that are well graded gave the highest compressive strength; while the poorly graded sands gave lower strengths. Okhuahia river sand gave the strongest concrete followed by Ikpoba, and Ovia river sands, Okhuahia, Ikpoba, Ovia and Okhoro erosion sands. Particle size distribution within a sand zone probably did not affect strength but the impurity content did. However, the inter-zonal differences in particle sizes probably did affect strength. The result also showed that only the river sands and Okhuahia erosion sand are good for concrete making.

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