scholarly journals Proportioning Self Compacting Concrete in Hot Weather Utilizing Limestone Powder

2019 ◽  
pp. 6-10
Author(s):  
Yousif Hummaida Ahmed
Keyword(s):  
Compressive Strength ◽  
Cement Content ◽  
The Self ◽  
Limestone Powder ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Concrete Properties ◽  
Slump Flow ◽  
Hot Weather ◽  
Powder Content

Self-compacting concrete (SCC) is a special type of concrete able to flow and compact under its self-weight. The SCC requires high powder content (mainly of cement) up to 600kg/m3 to achieve its properties. This will be problematic if all cement content in the powder exceeded 400 kg/m3used in hot weather of Sudan. This paper investigates addition of Sudanese limestone powder (LSP) to reduce cement content. The LSP dosages between 20% and 28 % (by cement weight) are used in six mixes having maximum cement content 380kg/m3. Results show that five trial mixes achieved the self-compactibility tested by slump flow, sieve segregation, V-funnel and U-box tests. Compressive strength of these mixes show that the LSP increases strength with dosage. Therefore, further investigations of hardened concrete properties are recommended for the successful mixes to be applied in real projects in the Sudan. Also, it has been found that dry batching and forced-action pan mixers are the most suitable for producing SCC with high homogeneity compared to commercial tilted-drum mixers.

scholarly journals Effects of Limestone Powder on Self-compacting Concrete Properties

2021 ◽  
Vol 9 (2) ◽  
pp. 14-20
Author(s):  
Yousif Hummaida Ahmed ◽  
Khalid Salah Eldin Babikir
Keyword(s):  
Compressive Strength ◽  
Cement Content ◽  
Dilution Effect ◽  
Tropical Climate ◽  
Limestone Powder ◽  
Fresh Properties ◽  
Self Compacting Concrete ◽  
Concrete Properties ◽  
Powder Content ◽  
Powder Type

Powder type of self-compacting concrete (SCC) needs high cement content to achieve self-compactibility, this will be undesirable in tropical climate of Sudan due to implication of high hydration heat. This paper investigates reducing cement content up to 340 Kg/m3 by blending limestone powder (LSP) up to 15 % as replacement of cement weight. Therefore, fifteen mixes having maximum powder content (P) of 400 Kg/m3 have been carried out with four water/powder ratios (W/P) (0.35, 0.4, 0.43 and 0.45). Fresh properties and compressive strength of SCC were measured. Results show most of the mixes have achieved self-compactibility in the fresh stages. However, the compressive strength of the mixes has been reduced with increased level of LSP replacing cement. This reduction in strength is caused by dilution effect of adds LSP.  

scholarly journals Estimating Slump Flow and Compressive Strength of Self-Compacting Concrete Using Emotional Neural Networks

2020 ◽  
Vol 10 (23) ◽  
pp. 8543
Author(s):  
Mosbeh R. Kaloop ◽  
Pijush Samui ◽  
Mohamed Shafeek ◽  
Jong Wan Hu
Keyword(s):  
Neural Network ◽  
Compressive Strength ◽  
Fly Ash ◽  
Pearson Correlation ◽  
Limestone Powder ◽  
Group Method ◽  
Self Compacting Concrete ◽  
Slump Flow ◽  
Powder Content ◽  
The Impact

The characteristics of fresh and hardened self-compacting concrete (SCC) are an essential requirement for construction projects. Moreover, the sensitivity of admixture contents of SCC in these properties is highly impacted by that cost. The current study investigates to estimate the slump-flow (S) and compressive strength (CS), as fresh and hardened properties of SCC, respectively. Four developed soft-computing approaches were proposed and compared, including the group method of data handling (GMDH), Minimax Probability Machine Regression (MPMR), emotional neural network (ENN), and hybrid artificial neural network-particle swarm optimization (ANN-PSO), to estimate the S and 28-day CS of SCC, which comprises fly ash (FA), silica fume (SF), and limestone powder (LP) as part of cement by mass in total powder content. In addition, the impact of eight admixture components is investigated and evaluated to assess the sensitivity of admixture contents for the modelling of S and CS of SCC. The results demonstrate that the performance prediction of ENN model is more significant than other models in estimating S and CS characteristics of SCC. The overall of Pearson correlation coefficient, r, and root mean square error (RMSE) of ENN model are 97.80% and 20.16 mm, respectively, for the S. These are 96.07% and 2.59 MPa, respectively, for the CS. Furthermore, the sensitivity of the powder content of fly ash is shown to have a high impact on the estimated S and CS values of SCC.

Fresh, Durability and Mechanical Behavior of Self Consolidating Concrete Incorporating Fly Ash and Admixture under Hot Weather

2021 ◽  
Vol 904 ◽  
pp. 453-457
Author(s):  
Samer Al Martini ◽  
Reem Sabouni ◽  
Abdel Rahman Magdy El-Sheikh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Weather Conditions ◽  
Chloride Penetration ◽  
The Self ◽  
Fresh Properties ◽  
Self Consolidating Concrete ◽  
Slump Flow ◽  
Hot Weather

The self-consolidating concrete (SCC) become the material of choice by concrete industry due to its superior properties. However, these properties need to be verified under hot weather conditions. The paper investigates the behavior of SCC under hot weather. Six SCC mixtures were prepared under high temperatures. The SCC mixtures incorporated polycarboxylate admixture at different dosages and prolonged mixed for up to 2 hours at 30 °C and 40 °C. The cement paste was replaced with 20% of fly ash (FA). The fresh properties were investigated using slump flow, T50, and VSI tests. The compressive strength was measured at 3, 7, and 28 days. The durability of SCC mixtures was evaluated by conducting rapid chloride penetration and water absorption tests.

scholarly journals Artificial Neural Network Estimation of the Effect of Varying Curing Conditions and Cement Type on Hardened Concrete Properties

Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 10 ◽  
Author(s):  
Gökhan Kaplan ◽  
Hasbi Yaprak ◽  
Selçuk Memiş ◽  
Abdoslam Alnkaa
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Limestone Powder ◽  
Mineral Admixtures ◽  
Hardened Concrete ◽  
Slag Cement ◽  
Curing Conditions ◽  
Concrete Properties ◽  
Concrete Production ◽  
Artificial Neural

The use of mineral admixtures and industrial waste as a replacement for Portland cement is recognized widely for its energy efficiency along with reduced CO2 emissions. The use of materials such as fly ash, blast-furnace slag or limestone powder in concrete production makes this process a sustainable one. This study explored a number of hardened concrete properties, such as compressive strength, ultrasonic pulse velocity, dynamic elasticity modulus, water absorption and depth of penetration under varying curing conditions having produced concrete samples using Portland cement (PC), slag cement (SC) and limestone cement (LC). The samples were produced at 0.63 and 0.70 w/c (water/cement) ratios. Hardened concrete samples were then cured under three conditions, namely standard (W), open air (A) and sealed plastic bag (B). Although it was found that the early-age strength of slag cement was lower, it was improved significantly on 90th day. In terms of the effect of curing conditions on compressive strength, cure W offered the highest compressive strength, as expected, while cure A offered slightly lower compressive strength levels. An increase in the w/c ratio was found to have a negative impact on pozzolanic reactions, which resulted in poor hardened concrete properties. Furthermore, carbonation effect was found to have positive effects on some of the concrete properties, and it was observed to have improved the depth of water penetration. Moreover, it was possible to estimate the compressive strength with high precision using artificial neural networks (ANN). The values of the slopes of the regression lines for training, validating and testing datasets were 0.9881, 0.9885 and 0.9776, respectively. This indicates the high accuracy of the developed model as well as a good correlation between the predicted compressive strength values and the experimental (measured) ones.

scholarly journals Compressive Strength by Incorporating Quarry Dust in Self-Compacting Concrete Grade M35

2018 ◽  
Vol 4 (4) ◽  
pp. 776 ◽  
Author(s):  
Mushtaq Ahmad ◽  
Sana Ullah ◽  
Aneel Manan ◽  
Temple Chimuanya Odimegeu ◽  
Salmia Beddu
Keyword(s):  
Compressive Strength ◽  
Strength Test ◽  
The Self ◽  
Kuala Lumpur ◽  
Self Compacting Concrete ◽  
Curing Period ◽  
Slump Flow ◽  
Compressive Strength Test ◽  
Super Plasticizer ◽  
Quarry Dust

The study has conducted to determine the workability and compressive strength of the self –compacting concrete. The sand has replaced with quarry dust with the proportion of 10, 20, 30 and 40% and super plasticizer was added 0.9%. The experiments were carried out at the Infrastructure University Kuala Lumpur (IUKL) concrete laboratory. Slump flow, J- Ring tests were carried out to determine the workability of self-compacting concrete and compressive strength test was conducted on 7 days and 28th days of curing period. A finding of the study shows that workability and compressive strength has increased by addition of quarry dust. It is concluded that addition of quarry dust up to 30%  improve the workability of the self-compacting concrete and further addition of quarry dust decrease the workability. Additionally, compressive strength of the quarry dust modified self-compacting concrete shows the trend of higher compressive strength up to 30% addition of quarry dust with sand replacement and further addition decrease the compressive strength.

scholarly journals Effect of internal curing on performance of self-compacting concrete by using sustainable materials

2018 ◽  
Vol 162 ◽  
pp. 02017
Author(s):  
Nada Aljalawi ◽  
Amar Yahia AL-Awadi
Keyword(s):  
Compressive Strength ◽  
Lightweight Aggregate ◽  
Internal Curing ◽  
Modulus Of Rupture ◽  
Limestone Powder ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Curing Conditions ◽  
Compressive Strength Test

This paper is devoted to investigate the effect of internal curing technique on the properties of self-compacting concrete. In this study, self-compacting concrete is produced by using limestone powder as partial replacement by weight of cement with percentage of (5%), sand is partially replaced by volume with saturated fine lightweight aggregate which is thermostone aggregate as internal curing material in three percentages of (5%, 10%, 15%) for self-compacting concrete, and the use of two external curing conditions which are water and air. The experimental work was divided into three parts: in the first part, the workability tests of fresh self-compacting concrete were conducted. The second part included conducting compressive strength test and modulus of rupture test at ages of (7, 28 and 90) days. The third part included doing the shrinkage test at age of (7, 14, 21, 28) days. The results show that internally cured self-compacting concrete has the best workability and the best properties of hardened concrete which include (compressive strength, modulus of rupture) of externally cured self-compacting concrete with both water and air as compared with reference concretes. Also, the hardened properties of internally cured self-compacting concrete with percentage of (5%) with thermostone aggregate is the best as compared with that of percentages (10% and 15%) in both external curing conditions. In general, the results of shrinkage test have shown reduction in shrinkage of internally cured self-compacting concrete as compared with reference concretes and this reduction increases with increase in the thermostone aggregate content-within-self-compacting-concrete.

scholarly journals Lightweight self-compacting concrete with sintered fly-ash aggregate

2018 ◽  
Vol 27 (3) ◽  
pp. 328-337
Author(s):  
Dorota Małaszkiewicz ◽  
Daniel Jastrzębski
Keyword(s):  
Fly Ash ◽  
Fresh Concrete ◽  
Strength Loss ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Self Compacting Concrete ◽  
Natural Sand ◽  
Concrete Properties ◽  
Slump Flow ◽  
Passing Ability

The article presents the results of research assessing the possibility of making LWSCC from the locally produced sintered fly ash aggregate CERTYD. Two methods of preliminary LWA preparation were applied: pre-soaking with water and coating with a film of cement paste. The following properties of fresh LWSCC were evaluated: slump-flow, time T500 and passing ability using L-Box. Partial replacement of natural sand by fine LW sand (0/0.5 mm) improved filling and passing abilities of fresh concrete, reduced slightly the bulk density, but it resulted in compressive strength loss by 12-18%. In terms of both fresh and hardened concrete properties it is more favorable to use only fine LW sand as natural sand replacement. Considering fresh concrete properties paste impregnation of LW aggregate is more efficient than saturation with water.

Effect of basalt, polypropylene and macro-synthetic fibres on workability and mechanical properties of self-compacting concrete

2019 ◽  
Vol 5 (2) ◽  
pp. 35
Author(s):  
Zinnur Çelik ◽  
Ahmet Ferhat Bingöl
Keyword(s):  
Mechanical Properties ◽  
Fresh Concrete ◽  
The Self ◽  
The Other ◽  
Fibre Content ◽  
Hardened Concrete ◽  
Fibre Reinforced Concrete ◽  
Self Compacting Concrete ◽  
Concrete Properties ◽  
Hardened Properties

In this study, the effects of different fibre types on the workability and mechanical properties of self-compacting concrete were investigated. Fresh and hardened properties of self-compacting concrete, different fibre content 0.90, 1.35 and 1.80 kg/m3 were evaluated using basalt, polypropylene and macro synthetic fibres with different fibre lengths of 24, 19 and 40 mm, respectively. The properties of fresh concrete were evaluated in terms of slump flowing, viscosity and flowability. In addition, compressive, flexural and splitting tensile strength were obtained from hardened concrete properties. To characterize mechanical properties 90 specimens were experimentally tested. The results show that the use of fibre reduces the workability of self-compacting concrete. On the other hand, tensile and flexural strength of the self-compacting fibre reinforced concrete increased with increasing fibre content, but it was determined that the fibre addition had no significant effect on the compressive strength.

scholarly journals The use of a volcanic material as filler in self-compacting concrete production for lower strength applications

2017 ◽  
Vol 67 (325) ◽  
pp. 111 ◽  
Author(s):  
D. Burgos ◽  
A. Guzmán ◽  
K. M.A. Hossain ◽  
S. Delvasto
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cementitious Material ◽  
Total Weight ◽  
Self Compacting Concrete ◽  
Lower Strength ◽  
Volcanic Material ◽  
Fine Powders ◽  
Slump Flow ◽  
Concrete Production

This study evaluates the use of large amounts of fine powders (fillers) derived from a Colombian volcanic material into the production of self-compacting concrete (SCC) for lower strength applications. The effects on SCC properties were studied with the incorporation of up to 50% of volcanic material of Tolima (MVT) as a partial substitute of the total weight of Portland cement. The workability was determined through slump flow, V-funnel, and L-box test. The compressive strength results were analyzed statistically by MINITAB. These demonstrated that 30% (by total weight of cementitious material) was the maximum allowable percentage of MVT to be used in the production of SCCs. Based on this, mechanical and permeability properties of SCC MVT 30% were evaluated at 28, 90 y 360 curing days. SCC MVT 30% exhibited compressive strength of 21 and 27 MPa after 28 and 360 days of curing, respectively.

scholarly journals Characterization of Gum Arabic As Viscosity Modifying Agent (VMA) for Producing Self-Compacting Concrete (SCC)

2021 ◽  
Vol 9 (2) ◽  
pp. 47-52
Author(s):  
Yousif Hummaida Ahmed ◽  
Moaz Ibrahim Rahamtalla ◽  
Khalid Salah Eldin
Keyword(s):  
Gum Arabic ◽  
Fresh Properties ◽  
Self Compacting Concrete ◽  
Acacia Senegal ◽  
Cement Ratio ◽  
Concrete Admixtures ◽  
Hot Weather ◽  
European Standards ◽  
Powder Content

This study aims at finding alternative indigenous Sudanese material for concrete admixtures that are necessary for casting concrete in hot weather of the Sudan. The objective of this study to classify Gum Arabic (GA) namely, Acacia Senegal (known locally as Hashab Gum) as viscosity modifying admixture (VMA) for lowering powder content in self compacting concrete (SCC). The methodology of the study is based on the European standards BS EN 934-2 & BS EN 480-15 that are used as a paradigm to classify GA as the VMA. Three trial SCC test mixes containing different quantity of cement, namely (400, 370 and 350) Kg/ as powder content. A dose of GA 0.2% by weight of cement is applied after being dissolved in water at a concentration of 30% by water weight. The water/cement ratio (W/C) is kept constant as 0.45 for all mixes. The results of this study showed that the 0.2% GA dosage is appropriate and satisfied all criteria set by BS EN 934-2: 2009 for VMA. Using 0.2% GA as VMA lower the powder of SCC from 400kg to 350kg/ while maintaining the SCC fresh properties.  

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