A Proposed Mix Design of Concrete with Supplementary Cementitious Materials by Packing Density Method

2020 ◽  
Vol 44 (2) ◽  
pp. 615-629 ◽  
Author(s):  
Badrinarayan Rath ◽  
Shirish Deo ◽  
Gangadhar Ramtekkar
Keyword(s):  
Packing Density ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Density Method

scholarly journals Concrete Mix Design for Completely Recycled Fine Aggregate by Modified Packing Density Method

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3535
Author(s):  
Yibo Yang ◽  
Baixi Chen ◽  
Yan Su ◽  
Qianpu Chen ◽  
Zhiji Li ◽  
...  
Keyword(s):  
Packing Density ◽  
Unit Price ◽  
Mix Design ◽  
Concrete Mixture ◽  
Fine Aggregate ◽  
Density Method ◽  
Concrete Mix Design ◽  
Recycled Fine Aggregate ◽  
Concrete Mix ◽  
Aggregate System

The undesirable properties of conventional recycled fine aggregate (RFA) often limit its application in the construction industry. To overcome this challenge, a method for preparing completely recycled fine aggregate (CRFA), which crushes all concrete waste only into fine aggregate, was proposed. The obtained CRFA had high apparent density, and its water absorption was lower than that of the conventional RFA. To take advantage of the CRFA, this paper introduced the modified packing density method for the CRFA concrete mix design. The modified packing density method took account of the powder with a particle size of smaller than 75 μm in the CRFA and balanced both the void ratio and the specific surface area of the aggregate system. Concrete (grade C55) was prepared using the CRFA to validate the feasibility of the proposed method. The unit price of the prepared CRFA concrete was around 12.7% lower than that of the natural aggregate concrete. Additionally, the proposed procedure for the concrete mixture design could recycle all concrete waste into the new concrete and replace all the natural fine aggregate in the concrete mixture.

scholarly journals Development of Green Geopolymer Binders Based on Construction and Demoliton Wastes

2021 ◽  
Author(s):  
Obaid Ur Rahman Mahmoodi
Keyword(s):  
Design Method ◽  
Setting Time ◽  
Ternary Systems ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Red Clay ◽  
X Ray ◽  
Chemical Factors ◽  
Red Clay Brick

This research focuses on the complete recycling of construction and demolition wastes (CDWs) to develop new green geopolymeric binders. An innovative mix design method based on (SiO2/Al2O3) and (Na2O/SiO2) chemical factors and liquids/solids (L/S) ratio was developed. The main focus was to optimize the compressive strengths of mixes incorporating mono, binary and ternary geopolymer systems of concrete waste (CW), red clay brick waste (RCBW) and ceramic tile waste (CTW). The effects of high temperature curing and the addition of supplementary cementitious materials (SCMs) were also investigated. Fresh properties comprising slump flow and setting time and mechanical characteristics including compressive strengths were investigated. Microstructural study was performed utilizing scanning electron microscopy (SEM), energy-dispersive X-Ray spectroscopy (EDS) and X-Ray Diffraction (XRD). This research proved the efficiency of the new mix design method in reaching high compressive strengths of mono-system of RCBW and CTW and all binary and ternary systems of geopolymer binders.

scholarly journals Meta-Analysis of Steel Fiber-Reinforced Concrete Mixtures Leads to Practical Mix Design Methodology

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3900
Author(s):  
Emilio Garcia-Taengua ◽  
Mehdi Bakhshi ◽  
Liberato Ferrara
Keyword(s):  
Design Methodology ◽  
Aggregate Size ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Data Driven ◽  
Validation Dataset ◽  
Maximum Aggregate Size ◽  
Steel Fiber Reinforced Concrete

The analysis of hundreds of SFRC mixtures compiled from papers published over the last 20 years is reported. This paper is focused on the relationships between the size and dosage of steel fibers and the relative amounts of the constituents of SFRC mixtures. Multiple linear regression is applied to the statistical modeling of such relationships, leading to four equations that show considerable accuracy and robustness in estimating SFRC mixture proportions as a function of fiber content and dimensions, maximum aggregate size, and water-to-cement ratio. The main trends described by these equations are discussed in detail. The importance of the interactions between aggregates, supplementary cementitious materials, and fibers in proportioning SFRC mixtures, as well as implications for workability and stability, are emphasized. The simplicity of these data-driven equations makes them a valuable tool to guide the proportioning of SFRC mixtures. Their predictive performance when used together as a data-driven mix design methodology is confirmed using a validation dataset.

Triple Blending with Superfine Natural Zeolite and Condensed Silica Fume to Improve Performance of Cement Paste

2017 ◽  
Author(s):  
P.L. Ng ◽  
J.J. Chen ◽  
A.K.H. Kwan
Keyword(s):  
Silica Fume ◽  
Cement Paste ◽  
Packing Density ◽  
Natural Zeolite ◽  
Water Film ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Concrete Production ◽  
Fine Size ◽  
Condensed Silica Fume

Superfine natural zeolite (SNZ) is obtained by grinding natural zeolite to micro-fine size, whereas condensed silica fume (CSF) is by-product of ferrosilicon industry. Both SNZ and CSF are environmentally-friendly supplementary cementitious materials for mortar and concrete production. Owing to the high fineness and favourable grading of SNZ and CSF (the median particle sizes were 4 μm and 0.4 μm, respectively), the addition of SNZ and CSF could successively fill the voids between ordinary Portland cement (OPC) grains and increase the packing density of the binder, so as to reduce the volume of voids to be filled with water. Therefore, triple blending of OPC+SNZ+CSF can benefit the overall performance of cement paste by releasing more water for flowability improvement at the same water/binder (W/B) ratio, or adopting a lower W/B ratio for strength improvement at the same flowability requirement. This study evaluated the effects of adding SNZ and CSF on the packing density and water film thickness of binder. The experimental results proved that triple blending with SNZ and CSF could increase the packing density and improve the flowability and cohesiveness of cementitious paste.

scholarly journals Fundamental Fresh State Properties of Self-Consolidating Concrete: A Meta-Analysis of Mix Designs

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Emilio Garcia-Taengua
Keyword(s):  
Meta Analysis ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Mathematical Framework ◽  
Self Consolidating Concrete ◽  
Fundamental Properties ◽  
Time Flow ◽  
Fresh State ◽  
Complex Relationships

The study reported in this paper is the first meta-analysis aimed at obtaining statistical models for the fresh state behavior of self-consolidating concrete (SCC) mixes which effectively reproduce the complex relationships between mix design and fresh state performance. A database compiled with data from more than 120 different sources was analyzed. This study proves that SCC fresh state performance is determined by three fundamental, uncorrelated properties: flow time, flow spread, and resistance to segregation, which constitute a robust mathematical framework for the optimization of SCC mixes. The models obtained for these fundamental properties have proved consistent and reproduce very well the general trends and interactions implicit in SCC mix design recommendations, which in effect constitute the mathematical validation of recommendations well sanctioned by practice. It has been proved that, if no supplementary cementitious materials (SCMs) are used, there is a remarkably narrow margin in which the three fundamental properties of fresh SCC mixes can be simultaneously optimized. The most stable mixes were found to be associated with sand-to-coarse aggregate ratios of at least 1.1. The flowability of SCC mixes in terms of both flow times and flow spread can be optimized when the following conditions concur: w/c ratio of 0.45, SCMs content below 100 kg/m3, and sand content not lower than 750 kg/m3. Furthermore, it was also proved that, in general, it is best to keep the dosages of superplasticizers (HRWRs) and viscosity-modifying agents (VMAs) below 1.7% and 0.7%, respectively, subject of course to variation across the different types of products available.

scholarly journals Development of Green Geopolymer Binders Based on Construction and Demoliton Wastes

2021 ◽  
Author(s):  
Obaid Ur Rahman Mahmoodi
Keyword(s):  
Design Method ◽  
Setting Time ◽  
Ternary Systems ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Red Clay ◽  
X Ray ◽  
Chemical Factors ◽  
Red Clay Brick

This research focuses on the complete recycling of construction and demolition wastes (CDWs) to develop new green geopolymeric binders. An innovative mix design method based on (SiO2/Al2O3) and (Na2O/SiO2) chemical factors and liquids/solids (L/S) ratio was developed. The main focus was to optimize the compressive strengths of mixes incorporating mono, binary and ternary geopolymer systems of concrete waste (CW), red clay brick waste (RCBW) and ceramic tile waste (CTW). The effects of high temperature curing and the addition of supplementary cementitious materials (SCMs) were also investigated. Fresh properties comprising slump flow and setting time and mechanical characteristics including compressive strengths were investigated. Microstructural study was performed utilizing scanning electron microscopy (SEM), energy-dispersive X-Ray spectroscopy (EDS) and X-Ray Diffraction (XRD). This research proved the efficiency of the new mix design method in reaching high compressive strengths of mono-system of RCBW and CTW and all binary and ternary systems of geopolymer binders.

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