Effective Reduction of Cement Content in Pavement Concrete Mixtures Based on Theoretical and Experimental Particle Packing Methods

2021 ◽  
Vol 33 (10) ◽  
pp. 04021277
Author(s):  
Miras Mamirov ◽  
Jiong Hu ◽  
Yong-Rak Kim
Keyword(s):  
Cement Content ◽  
Particle Packing ◽  
Concrete Mixtures ◽  
Effective Reduction ◽  
Experimental Particle ◽  
Pavement Concrete

scholarly journals Mechanical Strengths of Sawdust-Ash-Admixed Gum Arabic Concrete

2021 ◽  
Vol 8 (1) ◽  
pp. 12-29
Author(s):  
Augustine Uchechukwu Elinwa
Keyword(s):  
Cement Content ◽  
Gum Arabic ◽  
Strength Ratio ◽  
Design Strength ◽  
Conventional Concrete ◽  
Cement Material ◽  
Cement Ratio ◽  
Setting Times ◽  
Concrete Mixtures ◽  
Mechanical Strengths

Gum Arabic and sawdust ash were used both as an emulsifier admixture and supplementary cement material to address some of the gaps between pozzolanic and conventional concretes. Four concrete mixtures of 1: 2.24: 2.71, with a water-cement ratio of 0.5, and cement content of 370 kg/m3, was used. The concrete mixtures were designated as M-00, M-00GA, M-10GAS, and M-30GAS, signifying the control, control with gum Arabic (GA), and mix with both gum Arabic and sawdust ash (GAS), respectively. The dosage was 0.5 % of GA and the SDA replacement by wt. % was at 10 % and 30 %, respectively. The concrete samples were cured for 90 days, and tested for mechanical strengths. The results showed that adding GA alone to concrete mixture improved the mechanical strengths of the concrete and the gum Arabic acted like an accelerator. When both GA and SDA were used together in the dosage of 0.5 % with 10 % and 30 % proportions respectively, the mechanical strengths of the concrete decreased. The findings also reported that the two-third strength ratio at 28-days of curing which is used for the conventional concrete in stripping the formwork, may not be appropriate for use on pozzolanic concrete. This is because of the delay in setting times and thus, attaining the required design strength. Therefore, it is proposed to be taken at an age beyond 28 days of curing to carter for the pozzolanic effects which starts well above 28-days.

scholarly journals Effect of Flyash Addition on Mechanical and Gamma Radiation Shielding Properties of Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Kanwaldeep Singh ◽  
Sukhpal Singh ◽  
Gurmel Singh
Keyword(s):  
Gamma Radiation ◽  
Attenuation Coefficient ◽  
Cement Content ◽  
Mass Attenuation Coefficient ◽  
Radiation Shielding ◽  
Mechanical Parameters ◽  
Cement Ratio ◽  
Concrete Mixtures ◽  
Water To Cement Ratio ◽  
Shielding Properties

Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50%, and 60% of flyash replacing the cement content and having constant water to cement ratio. The testing specimens were casted and their mechanical parameters were tested experimentally in accordance with the Indian standards. Results of mechanical parameters show their improvement with age of the specimens and results of radiation parameters show no significant effect of flyash substitution on mass attenuation coefficient.

Improving the Durability of High Early Strength (HES) Concrete Patching Materials for Concrete Pavements

2020 ◽  
Vol 2674 (8) ◽  
pp. 12-23
Author(s):  
Cameron Wilson ◽  
W. Jason Weiss
Keyword(s):  
Cement Content ◽  
Autogenous Shrinkage ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Strength Development ◽  
Concrete Pavements ◽  
Shrinkage Cracking ◽  
Concrete Mixtures ◽  
Water To Cement Ratio ◽  
Early Strength

High early strength (HES) concrete patching materials are increasingly used to repair damaged pavements. The use of HES concrete enables the repaired pavement to be opened to traffic shortly after the repair has been installed; for example, opening pavements to traffic 4–6 h after the concrete is placed is becoming more common. HES concrete mixtures are typically designed with a low water-to-cement ratio and a high cement content; they contain accelerating admixtures and limited supplementary cementitious materials. As a result, these HES patches may be susceptible to self-desiccation, causing autogenous shrinkage and early age cracking. Self-desiccation can lead to reduced hydration, limited strength gain, and overestimation of strength development in maturity-based predictions. The objectives of this study are threefold. First, the paper will illustrate how self-desiccation can lead to the premature cessation of hydration and increased potential for shrinkage cracking. Second, the paper will illustrate how maturity-based predictions can be modified to account for self-desiccation. Third, internal curing is discussed as a way to mitigate self-desiccation and shrinkage ultimately improving the performance of HES concrete patching materials.

scholarly journals A New Approach for Designing Fluid Concrete with Low Cement Content: Optimization of Packing Density of Aggregates

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4082
Author(s):  
Ning Zhang ◽  
Wenqiang Zuo ◽  
Wen Xu ◽  
Shenyou Song
Keyword(s):  
Compression Strength ◽  
Packing Density ◽  
Cement Content ◽  
Drying Shrinkage ◽  
Simple Method ◽  
New Approach ◽  
Concrete Mixtures ◽  
Slump Flow ◽  
Cementitious Binder ◽  
Hardened Properties

The current study aims at proposing a novel and simple method for designing fluid concrete such as self-compacting concrete (SCC) with a low cementitious binder content to reduce the carbon footprint. Different testing methods regarding the packing density of aggregate mixtures are performed and compared. The W/C was determined according to the target compression strength. Slump flow spread is carried out to determine the most appropriate superplasticizer (SP) dosage and aggregate volume fractions and proportions in concrete mixtures. Furthermore, hardened performance, including compression strength and drying shrinkage of the fluid concrete, are characterized. Finally, a mix design process of fluid concrete with low cement content was proposed based on the preferred fresh and hardened properties of the concrete mixtures.

scholarly journals Correlating the Durability Properties of Roller Compacted Concrete

2021 ◽  
Vol 1 (3) ◽  
pp. 23-27
Author(s):  
Saad Issa Sarsam
Keyword(s):  
Cement Content ◽  
Point Of View ◽  
Test Results ◽  
Environment Modeling ◽  
Roller Compacted Concrete ◽  
Concrete Mixtures ◽  
Future Behavior ◽  
Density Relationship ◽  
Lower Porosity ◽  
The Relationship

Roller compacted concrete is the zero-slump concrete mixture, usually prepared at low cement content and low workability, and subjected to compaction by rollers to increase the density and improve the aggregate particles interlock. It is recommended for heavy duty pavement and can withstand harsh environment. Modeling the physical behavior of roller compacted concrete exhibits a quick and easy start to predict the future behavior of the material. In the present assessment, roller compacted concrete mixtures have been prepared in the laboratory using three percentages of Portland cement (10, 12, and 16) % to simulate low, medium, and high cement content from roller compacted concrete point of view. The mixtures were poured into the cylinder mold of 101.6 mm diameter and 116.4 mm height in five successive layers. Each layer had practiced 25 blows of the modified Proctor hammer with 4.5 kg weight, falling from 450 mm height. Specimens were withdrawn from the mold after 24 hours and cured for 28 days in a water bath at 20°C. Specimens were subjected to bulk density, absorption, and porosity determination. Test results were analyzed and modeled. It can be observed that the gradation of aggregates (dense or gap)does not exhibit a significant issue in the absorption-density relationship. However, Dense gradation exhibits lower porosity than gap gradation. It can be concluded that the obtained mathematical models may be implemented to predict the relationship between the durability parameters of roller compacted concrete in terms of porosity, absorption, and density with high coefficients of determination.

scholarly journals Towards Efficient Use of Cement in Ultra High Performance Concrete

2021 ◽  
Vol 65 (2) ◽  
pp. 81-105
Author(s):  
Ingrid Lande ◽  
Rein Terje Thorstensen
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Cement Content ◽  
Research Society ◽  
Particle Packing ◽  
Experimental Program ◽  
Inert Material ◽  
Ultra High Performance Concrete ◽  
Flexural Tensile Strength ◽  
By Products

Abstract This paper presents an investigation on substituting the cement content with an inert material, in a typical locally produced UHPC mix. A structured literature review was performed to enrichen the discussion and to benchmark the results towards already reported investigations in the research society. Investigations on cement substitution in UHPC are frequently reported. However, usually the cement is substituted with other binding materials – often pozzolanic by-products from other industries. Reports from investigations on the use of inert materials for cement substitution in UHPC seem scarce. An experimental program that included a total of 210 test specimens was executed. This program included evaluating several questions embedded to the problem on how to substitute cement while keeping all other variables constant. It is concluded that up to 40% of the cement can be substituted with an inert material, without significantly changing the flexural tensile strength or compressive strength of the hardened UHPC. Two preconditions were caretaken: the particle packing was maintained by securing that the substitution material had a Particle Size Distribution (PSD) near identical to the cement and that the water balance was maintained through preconditioning of the substitution material. Suggestions are made for improving benchmarking.

scholarly journals Reduction of cement content using graded aggregates in concrete production

2021 ◽  
Vol 7 (3) ◽  
pp. 125-135
Author(s):  
Benjamin Okwudili Mama ◽  
Chinedu Christian Asogwa ◽  
Boniface Obi Ugwuishiwu ◽  
Samson Nnaemeka Ugwu
Keyword(s):  
Compressive Strength ◽  
Cement Content ◽  
Concrete Mixtures ◽  
Concrete Properties ◽  
Splitting Test ◽  
Concrete Production ◽  
Concrete Mix ◽  
Different Shapes ◽  
Concrete Testing ◽  
Aggregate Shape

The aim of this project was to reduce cement content in concrete mixtures by changing the aggregate grading. For this purpose, concrete mixtures were made with aggregates having different shapes, textures, and grading. However, the workability of concrete mix depends on its paste volume, paste composition, and the type of aggregate used. Concrete testing was performed, and concrete properties including slump, compressive strength, and tensile splitting test were tested. The effect of aggregate shape on workability was evaluated by comparing one aggregate combination to another. It was found that the aggregate combination with S/A= 0.4 GR-B-CA+NA-A-FA had optimum workability properties and generally, GR-B-CA+NA-A-FA consistently had the highest workability, as well as the highest paste volume demand. This can be attributed to its poor grading as a result of the gaps in GR-B-CA content. Compared with NA-A-CA + NA-A-FA, it resulted in concrete mixtures with lower paste volume demand.

The Design of Reactive Powder Concrete (RPC) Mixtures Using Aceh Quartzite Powder

2021 ◽  
Vol 892 ◽  
pp. 43-50
Author(s):  
Yulius Rief Alkhaly ◽  
Abdullah ◽  
Husaini ◽  
Muttaqin Hasan
Keyword(s):  
Silica Fume ◽  
Cement Content ◽  
Fine Sand ◽  
Particle Packing ◽  
Mix Design ◽  
Reactive Powder Concrete ◽  
Dense Matrix ◽  
Steam Curing ◽  
Quartzite Powder ◽  
Reactive Powder

Original reactive powder concrete (RPC) consists of a large amount of cement, fine sand, crushed quartz, and silica fume, with a very dense matrix achieved by optimizing the granular packaging of the materials. This study, therefore, applied the modified Andreasen & Andersen particle-packing model using Aceh quartzite powder to design a densely compacted matrix and low cement content RPC mixtures. The research involved the preparation of two series of the mixture with different percentages of silica fume and Aceh quartzite powder and the 70.7 mm cube specimens were treated with combined steam curing and normal curing after which their compressive strength was tested at the age of 7 days and 28 days. The result showed the use of 61% local quartzite powder by weight of cement through an optimized mix design and cured treatment improves the RPC strength at any variation of silica fume.

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