Fig 1 - uploaded by Bishwajit Bhattacharjee
Content may be subject to copyright.
Source publication
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 voids between large particles with smaller particles and so on, in order to obtain a dense and stiff particle structure. Higher degree of particle packing...
Contexts in source publication
Context 1
... and the bulk density of each mixture is determined. Addition of smaller size aggregate (12.5mm down size) increases the bulk density. However a stage is reached when the bulk density of coarse aggregate mixture, which instead of increasing, decreases again. The results of Bulk density of coarse aggregate fractions(20mm and 12.5mm) are plotted in Fig. ...
Context 2
... compressive strength (7 days curing) vs water cement ratio for packing density data alone. Similarly Fig. 8 is a plot of compressive strength (7 days curing) vs water cement ratio including IS code and packing density method. Similar plots were obtained for 28 days curing age and they are represented in fig 9 (packing density alone) and fig. 10 (including both IS and packing density method). From fig 7 it is observed that a linear fit with a very good co-relation co-efficient i.e., 0.984 is obtained. Co-efficients a, b, standard error and co-efficient of co-relation for all the figures from 7 to 10 are presented in Table 7. From the table it is observed that a very good ...
Context 3
... good co-relation co-efficient is obtained for both the data (IS and packing density method) at 7 days and 28 days i.e., 0.953 and 0.961 respectively. Fig 11 represents compressive strength vs paste content in excess of void content for the data of packing density alone at 7 days curing age and fig 12 represents compressive strength vs paste content in excess of void content for the data of including both IS code and packing density method at 7 days curing age. Similar plots were obtained for 28 days curing age and they are presented in fig 13 (packing density alone) and fig 14 (including both IS and packing density method). ...
Context 4
... 11 represents compressive strength vs paste content in excess of void content for the data of packing density alone at 7 days curing age and fig 12 represents compressive strength vs paste content in excess of void content for the data of including both IS code and packing density method at 7 days curing age. Similar plots were obtained for 28 days curing age and they are presented in fig 13 (packing density alone) and fig 14 (including both IS and packing density method). From fig 11 to 14 it is observed that a linear fit with very good co-relation co-efficient is obtained. ...
Context 5
... plots were obtained for 28 days curing age and they are presented in fig 13 (packing density alone) and fig 14 (including both IS and packing density method). From fig 11 to 14 it is observed that a linear fit with very good co-relation co-efficient is obtained. From the Table 7 it is observed that a very good co-relation co-efficient is obtained for packing density alone at the curing age of 7 days and 28 days i.e., 0.995 and 0.998 respectively. ...
Similar publications
Concrete is the most commonly used, as construction material, in large-scale constructions where strength, workability, and durability are main requirements. Professionals are continuously improving the performance and strength of concrete with the help of innovative chemical admixtures and supplementary cementitious materials. The main benefits of...
Self Compacting Concrete (SCC) is a technology which is developing today in which concrete solidifies by itself without using vibrator. Casting conventional concrete which has a lot of reinforcement bars sometimes finds difficulty in achieving optimal solidity. The method used to solve this problem is by using SCC technology. SCC was made by using...
In this paper, the influence of external and internal effect of sulphate on normal and high performance concrete was studied. The aim of this experimental study is to evaluate the effect of external severe sulphate solution on compressive strength of concrete mixes containing two different internal sulphate. The experimental work included of castin...
Results of Compressive strength test and slump test of concrete containing Metakaolin and CKD at varying replacement levels are discussed and are compared with those obtained with the control (pure Portland cement concrete). The total partial replacement was considered in the range of 0% (i.e. control) to 50% by weight in steps of 10%. The combinat...
The mix design of ultra-high performance concrete (UHPC) is complicated by the presence of many “ingredients.” The fundamental packing density allows a simpler mix design with fewer ingredients to achieve optimum packing density and dense microstructure. The optimum particle grading increases the flowability of UHPC and eliminates entrapped air. Th...
Citations
... Pembuatan dan perawatan benda uji Pembuatan benda uji dilakukan mengikuti prosedur penelitian yang dilakukan (Alkhaly et al., 2021) yaitu diawali dengan mencari proporsi material RPC menggunakan bantuan software EMMA (Elkem Material Mixture Analyzer) yang perhitungan dan penampilan distribusi ukuran partikel dari suatu campuran dengan menggunakan metode packing density. Rancangan campuran yang direncanakan dengan metode Modified Andreasen and Andersen Model (Raj, G Patil and Bhattacharjee, 2014;Elkem., 2016). ...
p align="center"> Abstrak
Reactive Powder Concrete (RPC) merupakan jenis dari beton mutu ultra tinggi dengan karakteristik kuat tekan, dan kuat lentur yang sangat tinggi. Komponen penyusun RPC semen dengan kandungan yang tinggi, bahan yang sangat halus berupa silika dalam jumlah tinggi, dan tanpa agregat kasar. Pada penelitian ini dilakukan tinjauan sifat mekanis berupa uji kuat tekan dan kuat lentur RPC melalui perlakuan uap dengan abu sekam padi sebagai alternatif material pozzolan. Pengujian kuat tekan dilakukan pada kubus berukuran 70,7 x 70,7 x 70,7 mm umur 7 hari dan 28 hari, dan kuat lentur pada balok berukuran 70,7 x 70,7 x 300 mm umur 28 hari. Variasi abu sekam padi digunakan 15%, 20%, 25%, 30% dan 35% dari berat semen dengan jumlah benda uji sebanyak 3 sampel per variasi. Perawatan uap dimulai setelah satu hari pengecoran selama 72 jam pada suhu 90℃ kemudian dilakukan perendaman. Hasil pengujian menunjukan bahwa kuat tekan tertinggi umur 7 hari diperoleh pada variasi abu sekam padi 30% dan merupakan yang paling optimum dengan kuat tekan sebesar 108,37 MPa, selanjutnya pada RPC umur 28 hari kuat tekan tertinggi diperoleh pada variasi ASP 35% sebesar 116,59 MPa. Kemudian kuat lentur RPC tertinggi umur 28 hari diperoleh pada variasi abu sekam padi 30% dan merupakan yang paling optimum dengan kuat lentur sebesar 13,80 MPa. Hal ini menunjukkan bahwa abu sekam padi pada campuran RPC melalui perlakuan uap dapat dijadikan alternatif material pozzolan untuk menghasilkan kuat tekan dan kuat lentur RPC yang tinggi.
Kata Kunci: Reactive Powder Concrete , Abu sekam padi, Kuat tekan , Kuat lentur, Perawatan uap
Abstract
Reactive Powder Concrete (RPC) is a type of ultra high quality concrete with very high compressive strength and flexural strength characteristics. High-content cement, a very fine material with a high silica content, and no coarse aggregate are the components of RPC. In this study, rice husk ash (RHA) was used as an alternative pozzolanic material, and steam treatment was utilized to study the mechanical properties of RPC through compressive strength and flexural strength tests. Examinations of compressive strength were performed using cubes of 70.7 x 70.7 x 70.7 mm at 7 days and 28 days, while tests of flexural strength were performed using beams size 70.7 x 70.7 x 300 mm at 28 days. With a total of three samples for each variation, rice husk ash was employed at rates of 15%, 20%, 25%, 30%, and 35% by weight of cement. After casting for one day at 90°C for 72 hours, steam treatment started before being submerged in water. The results revealed that the 30% variation of rice husk ash had the highest compressive strength at 7 days, with an optimal compressive strength of 108.37 MPa, followed at 28 days by the 35% variation of RHA, with a maximum compressive strength of 116.59 MPa. Furthermore, the highest flexural strength of RPC at 28 days ages was obtained at 30% variation of rice husk ash and was the optimum with a flexural strength of 13.80 MPa. This study indicates that rice husk ash can be utilized as a substitute pozzolanic material in RPC mixes to develop high compressive and flexural strengths.
Keywords: R eactive Powder Concrete , Rice husk ash, Compressive strength, Flexural strength, Steam curing. </p
... The mix design was obtained by the packing density method of the aggregates with reference to Raj et al. [40]. The optimum bulk density was obtained by varying the percentage of CA to Malmesbury sand (henceforth called MS) in different proportions at 90:10, 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, and 50:50. ...
The production of Portland cement (PC) is associated with carbon emissions. One-part geopolymer "just add water" is a user-and environmentally-friendly binder that can potentially substitute PC. However, there is limited research on the setting time, fresh, and strength properties of one-part metakaolin (MK)-based geopolymer concrete (OMGPC) incorporating recycled aggregates. Hence, the study explored the fresh, mechanical (compressive, flexural, splitting tensile, and E-modulus) and microstructural properties of ambient cured (7-, 28-, and 90-day) OMGPC containing recycled waste plastics (RESIN8) and recycled fine waste glass aggregate (FWG) at 5% and 10% by volume of the sand. The study result shows that 2% trisodium phosphate by wt. of the binder retard the initial and final setting times of OMGPC. At the same time, the incorporation of RESIN8 and FWG aggregates improved the workability of geopolymer concrete. The lightweight properties of RESIN8 aggregate reduce the hardened density of OMGPC, while the FWG specimens show a similar density to the control. The compressive strength of RESIN8 and FWG OMGPC range from 19.8 to 24.6 MPa and 26.9 to 30 MPa, respectively, compared to the control (26 to 28.9 MPa) at all curing ages. The flexural and splitting tensile strength of the OMGPC range from 2.2 to 4.5 MPa and 1.7 to 2.8 MPa, respectively. OMGPC is a viable alternative to Portland cement, and FWG can substitute sand in structural concrete by up to 10% and RESIN8 aggregate at 5% by volume of the natural sand.
... The concrete and mortar were proportioned to optimise packing density of available aggregates by following the method proposed by Raj et al. (2014) [31] . For concrete, the maximum packing density was obtained for a coarse-to-fine aggregate ratio of 55:45 by mass. ...
... The concrete and mortar were proportioned to optimise packing density of available aggregates by following the method proposed by Raj et al. (2014) [31] . For concrete, the maximum packing density was obtained for a coarse-to-fine aggregate ratio of 55:45 by mass. ...
This study utilises moisture distribution profiles harvested from literature and gravimetric observations made in the laboratory to analyse the robustness of three Boltzmann-profile, θn(ϕ) models which were previously adopted by various researchers for the modelling of non-linear hydraulic diffusivity, D(θn) of drying mortar and concrete. Such an analysis is necessary to ensure that the D(θn) data is reliable and free from modelling artefacts. A 2-parameter θn(ϕ) model is found to be better suited for the inverse estimation of D(θn) in comparison to a widely used 3-parameter model. The 2-parameter model captures the effects of water-to-cement ratio and temperature on D(θn) in accordance to the physics of the drying phenomenon. Also, it does not cause a sudden drop in the diffusivity curve near high saturation levels as is noted with the 3-parameter model. It is further noted that the 3-parameter θn(ϕ) model fails to fit low θn - low ϕ data which is typically obtained using non-destructive imaging techniques. The 2-parameter model can fit low θn - low ϕ data and is also suitable for high θn - low ϕ data, obtained through gravimetric experiments, within the limit of θn < 0.80.
... The dry packing of a given particle skeleton refers to the solid fraction of the volume occupied by the skeleton when confined. This packing density is closely related to the minimal water addition needed to obtain a paste, i.e. a dense suspension [23,24]. The final water content will directly affect the water-cement ratio, and consequently control the mechanical features and the durability [22,25]. ...
High packing density is one of the key factors for obtaining ultra-high-performance cementitious materials in the hardened state. Packing density also plays a role in the fresh state, influencing various properties of dense suspensions, including rheological properties and stability, which are highly important in 3d printing applications. The maximum packing density of a specific mixture can be estimated by considering the geometrical properties and proportions of each component using the compressive packing model (CPM). This paper aims to utilize the CPM as an efficient tool for designing cementitious materials specifically tailored for large-scale 3D printing of mortar in bi-component printing systems, with a focus on maximizing the performance-to-environmental impact ratio. Two different sets of mixtures were prepared for this study. Set A consisted of cement, sand, and silica fume, while Set B utilized cement, multiple sands, and multiple limestone fillers. Within each group, various mixtures were tested on a small scale to validate their rheological properties, particularly the yield stress. Pumpability, extrudability and buildability were evaluated by utilizing these mixtures in different printing sessions. Additionally, the compressive strengths of these mixtures were characterized. Finally, a method for designing a printable mixture is presented, and efficient and printable formulations with low cement ratio are proposed and printed.
... Earlier works (Yu et al., 2015(Yu et al., , 2016 focused on selecting the aggregate fractions suitable for optimal distribution of the particle sizes based on the work by Andreasen and Andersen (1930). Raj et al. (2014) explored the packing of 20 mm, 12.5 mm and fine aggregates with a packing density method using bulk density (BD) calculation. Appropriate finer particles are chosen to fill the voids between the coarser particles to achieve the maximum packing density and yield desirable concrete properties. ...
Ultra-high-performance concrete meets the demand of modern infrastructure due to its exceptional strength and durability. The effect on concrete strength of size and shape of fine aggregates, and binder content and type, were investigated. Particle packing concepts were adopted for fine aggregate optimisation, and shape of the fine aggregate was assessed using an aggregate image measurement system. Further, the effects of binder content, binder type and curing age were investigated through compressive strength, thermos-gravimetric analysis and quantitative X-ray diffraction. Mixtures with 2.36 mm nominal maximum size of aggregate and angular aggregates exhibited higher compressive strength. No significant increase in the compressive strength beyond the optimum binder content of 1000 kg/m ³ was observed. The study also revealed that ultra-fine slag as a feasible alternative to silica fume. The thermos-gravimetric and X-ray results of concrete paste samples at different curing ages showed that the degree of hydration was relatively low (38.3%) with no further significant increase beyond seven days. This work contributes to the fundamental understanding of the effect of raw materials on ultra-high-performance concrete strength, which helps in rational selection of materials and mixture proportioning.
... Maximum reduction in density was noted in 40% SFA mixed concrete samples which were 2369 and 2356 kg/m 3 respectively for fresh and harden state. This decrement in density is mainly due porous and lower specific gravity of SFA particles as compared to conventional aggregates [9] [16]. ...
Conventional concrete pavement is more efficient towards mechanical load but combing with environmental loads compromises serviceability. This paper mainly focuses on utilizing sintered fly ash (SFA) aggregate to partially replace coarse aggregate in pavement quality concrete. Incorporating SFA aggregate in concrete pavement enhances the thermal behavior of rigid pavement due to higher voids and lower thermal conductivity. Coarse aggregate was partially replaced with SFA aggregate at an interval of 10 % till 40% by volumetric replacement. Pavement quality concrete (PQC) was designed as per Indian standards with a fixed water-cement ratio of 0.36 to achieve a minimum of 40 N/mm2 compressive strength. Compressive, split tensile and flexural strengths were inspected as mechanical behavior and thermal conductivity was examine as thermal behavior of different SFA mixed PQC. It has been observed that there is a slight decrement in mechanical strength by incorporating SFA in PQC but the thermal property of PQC was improved. Overall, it can be concluded that incorporating SFA at a certain level enhances the combined thermo-mechanical properties of PQC.
... The aggregate proportions and mix design were obtained by the packing density method [17], and the optimum proportion of the aluminosilicate precursors and activators was obtained through trial mixes using the Taguchi approach [18]. The proportion of CS to MK was 70:30, and 12% activator by weight of the binder was used. ...
The high demand for concrete in the construction industry leads to a high cement production rate, thereby increasing carbon emissions (CO2), resulting in global warming and detrimental effects on human survival. One-part "just add water" geopolymer binder is a potential sustainable binder that could substitute ordinary Portland cement. Currently, there are limited studies on the mechanical properties of one-part slag-metakaolin-based GPC with plastic waste as a substitute for fine aggregate. This paper presents the performance of a one-part slag-metakaolin-based geopolymer using anhydrous sodium silicate, sodium hydroxide and calcium hydroxide as activators. Also, the influence of 5% and 10% replacement of natural sand with RESIN8 (recycled plastic waste containing Resins 1-7) is also reported on the composite's fresh properties. Furthermore, the effects of two curing methods on the mechanical properties (compressive and flexural strength) are presented. Adding plastic waste as fine aggregate in concrete improved the workability, but there was a reduction in the mechanical strength of GPC as the percentage of RESIN8 increased. However, the compressive strength of 28 days water cured (WC) GPC with 5% and 10% RESIN8 were 25.6 MPa and 23.4 MPa, respectively, and ambient cured (AC) GPC with 5% and 10% RESIN8 were 24.1 MPa and 21.7 MPa, respectively.
... Reducing the voids also reduces the amount of water and cement paste required to bind the aggregate particles, since the volume of the space present in a dense pack mixture design is less. The packing factor method was adopted from Hoornahad [31] and Raj et al. [33]. This method was utilized to improve the material consistency of mixtures with lightweight aggregate content. ...
Concrete 3D printing is a sustainable solution for manufacturing efficient designs and creating less waste, and selecting the optimal materials to use can amplify the advantages of this technology. In this study, we explore printing lightweight concrete by replacing normal weight aggregate with lightweight aggregates such as cenospheres, perlite, and foam beads. We adopt a systematic approach to investigate mixtures using different formulation methods such as the specific gravity and packing factor methods to improve the printing and mechanical performances of the mixtures. The rheological results showed significant improvement in the flow characteristics of the different mixtures using both the specific gravity method and the packing factor method to formulate the mixtures. Furthermore, a statistical tool was used to achieve optimal performance of the mixtures in terms of high specific compressive strength, high flow characteristics, and good shape retention capability by maximizing the specific compressive strength ratio, slump flow, and the static yield stress, while minimizing the slump, dynamic yield stress, and plastic viscosity. With the above design objectives, the optimal percentages of the aggregate replacements (cenosphere, perlite, and EPS foam beads) were 42%, 68%, and 44%, respectively. Finally, the optimized results also showed that the mixture with cenosphere aggregate replacement had the highest specific strength.
... In the present study, the selection of the UHPC component is performed by the packing density method (PDM). PDM is one of the most effective methods for choosing the ingredient of concrete used for various types of concrete [12][13][14]. The general principle of the method is to choose a concrete mix composition to reduce pore spaces in the mixture and increase the overall hardness of the material [4,15]. ...
Ultra-High Performance Concrete (UHPC) improves the bearing capacity as well as the durability of structural concrete. This study aims to investigate the constituents of UHPC in both phases: aggregate and cementitious materials. The proper ratio of the mixture was chosen based on combining an aggregate gradation of quartz sand and crushed stone. In addition, the compressive strength of the hardened cement paste was investigated to achieve the optimal ratio of silica powder and blast furnace slag. The combination of aggregate (quartz sand and crushed stone) and cement paste (cement, silica fume, silica powder, and blast furnace slag) showed ultra-high performance. The compressive strength of UHPC reached 135.74 MPa at 7 days, corresponding to 90% of 28 days’ strength (150.98 MPa). The results of the present study provide a new mixture-proportioning for UHPC with economic efficiency. Moreover, the use of slag enhances concrete performance and reduces the negative environmental impact.
... The higher the F/C ratio (indicating the fine aggregate to coarse aggregate ratio), the better the packing density of all-in-aggregates due to lesser voids. This maximizes the density which in turn reduces the quantity of slag required and also helps in improving the engineering properties due to higher package density [20][21][22][23]. Compared to the conventional experimental works, the Response Surface Method (RSM) is a numerical computation modelling application that is also a subset of Design of Experiment (DOE). ...
The present work is aimed to utilize slag as the primary source of binder (aluminosilicate) in alkali activated concrete so that CO2 emissions can be reduced. Also, sand is partially replaced 20% by volume (constant) with Used Foundry Sand. Minitab’s response surface method is applied to optimize the mixing proportions and also to study the effect of independent variables (Slag, Alkali/Binder and Fine aggregate/Coarse aggregate) on the dependent variables (compressive strength at 3, 7 and 28 days of curing). The experimental compressive strength of the studied concrete is measured and compared with the predicted results of the response surface method and the predictions are in good agreement. The optimized independent variables, S = 416.418 kg/m3, A/B = 0.488 and F/C = 0.554 are also validated with another set of experiments and it is found that error is <10%. It can be concluded that Response Surface Method can be efficiently used in optimization.
