2. Particle Packing Model of Dewar. The particle packing method based on the voids ratio of materials was introduced by J.D. Dewar [] in 1999.The voids ratio is generally defined as the ratio of total void volume to total solid volume, and it is a function of the shape and surface texture of particles and of the grading in relation to the mean size of particles.
The packing density of individual aggregate in a volume fraction of total aggregate or over all aggregate is determined from its maximum bulk density of mixture and specific gravity from the following relation. Packing density = …
When selecting a concrete mix design, it is always desirable to compose the aggregates as densely as possible, i.e. with maximum packing. That minimises the necessary amount of …
Based on the particle packing structures in the cubic containers with semi-periodic boundaries, the effect of different aggregate characteristics on the variation of three parameters ((i.e., the volume fraction of aggregates V V, specific surface area of aggregates S V and minus third power of meaning free spacing between aggregates λ −3) is ...
The concrete mix design method proposed in this study was based on dense particle packing. Since the aggregate was a granular material with the largest proportion in concrete, the volume fraction of aggregate in the concrete prepared by this method increased to different degrees. The volume fraction of aggregate is shown in Table 9.
It is well known in concrete technology that the grading of aggregate is one of the main factors influencing the hardened concrete strength (Neville, 1995, Kumar Mehta and Paulo Monteiro, 2006).Aggregate is added to cement paste for various reasons: aggregate is cheaper than cement and it confers to concrete higher strength and better durability than cement paste.
In the present study, three of these particle packing methods i.e., Modified Toufar Method (MTM), J D Dewar method (JDD) and Compressible Packing Model (CPM) are used for the determination of gradation of coarse and fine aggregate and the optimum method of gradation is chosen based on the required type of concrete. The particle packing methods ...
Among the most important parameters affecting performance of concrete are packing density, compaction degree, and the corresponding particle size distribution (PSD) of aggregates. Better aggregate packing improves the main engineering properties of concrete: strength, modulus of elasticity, creep, and shrinkage.
These assemblies represent the real aggregate systems of portland cement concrete. Two variations of the algorithm are proposed: Sequential Packing Model and Particles Suspension Model. A developed multi-cell packing procedure as well as fine adjustment of the algorithm's parameters were useful to optimize the computational resources (i.e ...
The workability, strength, water absorption, voids and density tests of the produced concrete revealed that using EAF slag as a coarse aggregate gives promising concrete characteristics.
However, in the concrete prepared by Fuller grading curve, the content of coarse aggregate with large particle size is relatively high, which has no strong theoretical guidance for the workability of fresh concrete. Alfred's dense packing equation holds that the fine particles in concrete have a great influence on the workability of fresh ...
3. CHAPTER-1 Introduction - • Packing density is new kind of mix design method used to design different types of concrete; Normal concrete, high strength concrete, no-fines concrete and self compacting concrete. • The concept of packing density as a fundamental principle for designing High performance concrete (HPC) mixes • HPC has become more and …
packing density of the aggregate could be employed to increase the workability of the concrete at the same water/cementitious ratio or increase the strength of the concrete by reducing the …
The effect of aggregate characteristics on the variation of interfacial layers in the concrete is investigated. In this work, concrete material is treated as a two-phase composite composed of coarse aggregates and mortar matrix. The aggregates in the concrete are assumed to be a series of 3D superballs-shaped particles.
DOI: 10.1016/J.CONBUILDMAT.2010.01.010 Corpus ID: 136667339; Application of genetic algorithm for modeling of dense packing of concrete aggregates @article{Sobolev2010ApplicationOG, title={Application of genetic algorithm for modeling of dense packing of concrete aggregates}, author={Konstantin Sobolev and Adil Amirjanov}, …
The packing phenomenon for concrete is therefore significant on a meso-level as well as on a micro-level. Particle packing details will directly affect the characteristics of concrete. A high packing density of an aggregate can reduce the …
Regions representing the effective maximum packing and diluted packing of aggregates in concrete were identified, taking into account the dilution effect contributed by the cement paste. Aggregates located in the overlap between the diluted packing region and areas with low estimated chloride diffusivity were selected for the preparation of ...
The packing density of aggregate increased by 3.75%, 13.6% and 18.4% for natural aggregate and 14.86%, 19.5% and 27.7% for recycled concrete aggregate using the proportions obtained from MTM, JDD ...
A particle packing phenomenon exists in a wide range of engineering fields. For asphalt concrete mixtures, around 85% of the volume of dense graded hot mix asphalt (HMA) mixture is made up of aggregates [1].The aggregate structure and characteristics, particularly aggregate gradation, shape (angularity), and coarse aggregate surface texture, have been …
An alternative approach for the aggregate selection and combination is to aim for the aggregate mix which has the lowest void content or the maximal packing degree. This will lead to the lowest cement consumption, porosity and shrinkage and thus the concrete with the highest performance and the lowest price.
As a measure of how effectively aggregate fills a given volume, packing density is an essential topic in concrete technology. Packing more particles into a shared space reduces …
Packing density is new kind of mix design method used to design different types of concrete. To optimize the particle packing density of concrete, the particles should be selected to fill up the ...
Both natural and recycled aggregates characterization was performed through a water absorption at 24 h test and bulk density, according to the following standards: NBR NM 53 [25] for NCA and NBR NM 52 [26] for fine aggregates (NFA and FRCA). As the absorption is a major issue for the RCAs, the attached paste, responsible for this increase on absorption, was …
II. Design of Concrete Mix Using Packing Density Method Determination of aggregate fractions The packing density of aggregate mixture is defined as the solid volume in a unit total volume. The aim of obtaining packing density is to combine aggregate particles in order to minimize the porosity, which allows the use of least possible amount of ...
Recycled aggregate (RA) could be re-utilized in concrete paving blocks. However, the use of RA in concrete might lead to inferior performance, which constitutes a major barrier in the wider ...
In the concrete mixing, Wang's model could be used to simulate the aggregates' packing process, i.e., the crushed stone or cobblestone. As to the casting simulation, the packing process of cement particles could also be simulated based on this way.
The reuse of old concrete as a source of aggregate is a reliable alternative to Natural Aggregate (NA) in concrete construction. Because of poor quality of Recycled Aggregate (RA), the performance of Recycled Aggregate Concrete (RAC) is not up to the mark in fresh stage and hardened stage as compared to Natural Aggregate Concrete (NAC).
Packing density method of mix design is the only mix design method used for proportioning normal concrete, high strength concrete, no-fines concrete and self compacting concrete. No …
Packing of Aggregates and Concrete Mix Proportioning. As was emphasized in the case of high-performance concrete (HPC) (De Lar rard & Sedran, 1994; Sobolev, 2004), three fundamental relationships ...
A new approach for aggregate grading optimization for mixtures. F. Olard, S. Pouget, in Advances in Asphalt Materials, 2015 Abstract. Aggregate packing concepts developed in the field of high-performance cement concrete, were transposed to the field of asphalt concrete. These concepts, associated with the use of the gyratory compactor on aggregates only, enabled the …
An alternative mix design may often lead to a better and cheaper concrete. An alternative approach for the aggregate selection and combination is to aim for the aggregate …
Abstract. Designing concrete based on aggregate packing and optimized gradations can result in 25 % less cement content to reach a targeted compressive strength and less water-reducing admixture to obtain a required consistency. In this research, two studies were conducted: (1) an experimental analysis to determine the effects of aggregate packing on …
The study failed to discuss the packing particles of cement content or aggregate packing density as a basis for mix design. The investigation of Kumar and Santhanam [25] summarised the PPM to be used in selecting the concrete and mortar mix compositions by considering such factors as SCC, high performance/strength concrete in different ...
However, that method proved to be practicable only for PPM in Self-Compacting Concrete (SCC) and suitable only when there was a high cement ratio in the concrete matrix. Another issue with this study was that it focused on the entire concrete mix packing density rather than aggregate packing alone or cementitious materials.
The profiles of the sets of curves correspond well with respect to the maximum packing value, The theoretical 4C packing gives a highest packing grade for the aggregate composition 60% 0 – 0.5 mm, 0% 0.5 – 1 mm and 40% 1 – 2mm …
AbstractThis research investigates the effects of aggregate proportioning on the basis of theoretical particle packing models and verifies the predicted results with experimental data from compaction of concrete aggregates. The experimental, theoretical, ...
The goal of aggregate packing in concrete is to achieve the most efficient arrangement of particles. Engineers use packing models to determine the right proportions of coarse, medium, and fine aggregates. These models are based on particle size distribution (PSD), which shows the range of aggregate sizes in a mix. ...
In concrete-based composite design and construction, packing of aggregates is one of the most important challenges (Baulea and Makse, 2014, Li and Kwan, 2014, Ghasemi and Emborg, 2019).An ideal ...