A multiscale model for effective moduli of concrete incorporating ITZ water–cement ratio gradients, aggregate size distributions, and entrapped voids

2003 ◽  
Vol 33 (1) ◽  
pp. 103-113 ◽  
Author(s):  
J.C. Nadeau
Keyword(s):  
Aggregate Size ◽  
Multiscale Model ◽  
Size Distributions ◽  
Effective Moduli ◽  
Cement Ratio ◽  
Water Cement Ratio

Effect of maximum grain size on value of modulus of rupture reactive powder concrete

2020 ◽  
Vol 26 (1) ◽  
pp. 1-8
Author(s):  
Widodo Kushartomo ◽  
Dewi Linggasari ◽  
Arianti Sutandi
Keyword(s):  
Concrete Beam ◽  
Aggregate Size ◽  
Modulus Of Rupture ◽  
Reactive Powder Concrete ◽  
Fine Aggregate ◽  
Steam Curing ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Buckling Failure ◽  
Reactive Powder

Modulus of rupture (R) is a measurement of a tensile strengh of a concrete beam. The value of R is affected by the size of fine aggregat grain, the density of the concrete beam and the water-cement ratio. The unit of R is MPa expressing the tensile strength of the concrete beam without reinforcement to withstand a buckling failure. The distance between the supports of the concrete beam should not be less than three times of the height of the beam. In this research the size of the concrete beam speciment was 100 mm x 100 mm x 350 mm, the maximum fine aggregate size was varied (300 µm, 425 µm, and 600 µm) and the water-cement ratio was also varied (0.25, 0.22 and 0,20). All speciments were cured by steam curing and were tested after seven days. The results show that the larger the size of the fine aggregat grain and the higher the water-cement ratio, the smaller the R.

Permeability and Porosity of Pervious Concrete Containing Blast Furnace Slag as a Part of Binder Materials and Aggregate

2017 ◽  
Vol 266 ◽  
pp. 272-277 ◽  
Author(s):  
Jul Endawati
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Coarse Aggregate ◽  
Aggregate Size ◽  
Pervious Concrete ◽  
Partial Substitution ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Furnace Slag

The use of industrial by-products could provide a feasible solutions for the construction industry to reduce the strain on supply of natural aggregate as well as achieving the concept of environmentally friendly binder material by replacing part of Portland cement. This paper reports the results of an experimental study, mainly on the permeability and porosity characteristic of pervious concrete developed by substituting 26% Portland cement with air-cooled blast furnace slag and replacing part of natural coarse aggregate with granular blast furnace slag of different aggregate size and different water/cement ratio. The pervious concrete with lower water cement ratio and 25% GBFS affected either the porosity or the compressive strength of the pervious concrete. As expected, the porosity increased in pervious concrete with bigger aggregate size, but decreased when the smaller aggregate size was used. Partial substitution of coarse aggregate with granular GBFS of the same gradation size did not affect the permeability coefficient. Specimens developed using water cement ratio of 0.34 and coarser aggregate size tend to have a greater water permebility compared with those of 0.3 water/cement ratio.

Coefficients for Calculation of Deformation-Strength Characteristic of Concrete for Injection with Two-Stage Expansion

2018 ◽  
Vol 284 ◽  
pp. 922-928
Author(s):  
G.V. Nesvetaev ◽  
Y.I. Koryanova ◽  
T.N. Zhilnikova
Keyword(s):  
Portland Cement ◽  
Aggregate Size ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Technological Factors ◽  
Several Variables ◽  
Concrete Admixtures ◽  
Function Of Several Variables ◽  
The Impact ◽  
Kinetics Of

Strength of concrete is a function of several variables, such as: water / cement ratio, portland cement activity, filler quality, etc., adjusting which you can achieve the required strength. However, the introduction of the concrete admixtures, changing holding conditions of the samples, the volume restriction can affect the strength of the due to exposure impacts both the kinetics of hydration processes and on the structure formation of cement paste. The article presents the results of investigation the influence of the amount of gas-forming admixture, the presence, type and amount of superplasticizer, the ratio sand / cement, aggregate size and water-cement ratio on gassing and expansion of the mixture in the first stage and propose coefficient of effectiveness of gassing and of expansion. The authors proposed a formula to describe the dependence of the relative deformations of expansion of the concentration of aggregate. In order to assess the conditions in which there is a mixture, it is proposed to use the indicator - coefficient of congestion of expansion, to account for the influence of hardening conditions on the strength of the concrete - coefficient hardening conditions. The authors proposed to consider the impact of prescription and technological factors by introducing system of correction coefficients.

Influence of aggregate size on the mechanical and transport properties of concretes and concrete-equivalent mortars

2010 ◽  
Vol 37 (10) ◽  
pp. 1303-1314 ◽  
Author(s):  
Erdoğan Özbay
Keyword(s):  
Water Absorption ◽  
Transport Properties ◽  
Water Permeability ◽  
Aggregate Size ◽  
Maximum Aggregate Size ◽  
Test Results ◽  
Chloride Permeability ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Rapid Chloride Permeability

In this study, the influence of the aggregate size on the mechanical and transport properties of concrete and concrete-equivalent mortars is investigated. A concrete mixture was proportioned having a water–cement ratio of 0.45 and a cement content of 450 kg/m3 with a maximum aggregate size of 22.4 mm. Then, keeping the total aggregate surface area constant, three mixtures were proportioned with the same water–cement ratio, but the maximum aggregate size decreased to 16, 8, and 4 mm using the concrete-equivalent mortar method. Mechanical properties including compressive strength, splitting tensile strength and transport properties including rapid chloride permeability, water sorptivity, water absorption, and water permeability tests were performed at 7 and 28 d. Test results revealed that decreasing the maximum aggregate size increased the water permeability, rapid chloride permeability, water absorption, and sorptivity values, but decreased the compressive and split tensile strengths of concrete and concrete-equivalent mortars.

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