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Durability and service life
Published in Geert De Schutter, Damage to Concrete Structures, 2017
As described in the European code EN 206-1, paragraph 5.2.5.3, “The equivalent concrete performance concept permits amendments to the requirements in this standard for minimum cement content and maximum water/cement ratio when a combination of a specific addition and a specific cement is used, for which the manufacturing source and characteristics of each are clearly defined and documented”. The (informative) Annexe E of EN 206-1 provides further details of the equivalent concrete performance concept. “Testing should show that the performance of the concrete containing the addition should be at least equivalent to that of the reference concrete.” Furthermore, some general guidance is given in Annexe E, which can form the basis for an actual testing and acceptance procedure.
Mechanical Properties of Reinforced Concrete
Published in L.H. Martin, J.A. Purkiss, Concrete Design to EN 1992, 2005
BS EN 206-1 (2000) specifies the mix, transportation, sampling and testing of concrete. Concrete mixes are either prescribed, i.e. specified by mix proportions, or designed, i.e. specified by characteristic strength. For example, Grade C30P denotes a prescribed mix which would normally give a strength of 30 MPa; Grade C25/30 denotes a designed mix for which a cylinder strength of 25 MPa or cube strength of 30 MPa is guaranteed. The grades recommended by EN are from 12/15 to 50/60 in steps of approximately 5 MPa for normal weight aggregates. The lowest Grades recommended for prestressed concrete are C30 for post-tensioning and C40 for pretensioning.
Mainland Europe, Turkey and Cyprus
Published in Ian Sims, Alan Poole, Alkali-Aggregate Reaction in Concrete: A World Review, 2017
Isabel Fernandes, Özge Andiç-Çakir, Colin Giebson, Katrin Seyfarth
The Slovenian standard for concrete, SIST 1026 (2008), contains guidance on the application of SIST EN 206-1. In this standard, it is prescribed that, in the case of aggregates originating from the Mura or Drava river basins, it is necessary to verify their potential alkali-reactivity, although the methods to be used for such verification, as well as the criteria according to which the results should be evaluated, are not specified. Nowadays, the methods used for evaluations of this kind are ASTM C1260, or RILEM AAR-2, AAR-3 and AAR-4 (in Nixon & Sims, 2016).
A study of the rheological behaviour of eco-friendly mortar made with metakaolin and marble powder at various ambient temperatures
Published in European Journal of Environmental and Civil Engineering, 2023
H. Dada, H. Soualhi, A. S. E. Belaidi, E-H. Kadri, B. Benabed
The principle of the concrete equivalent mortar (CEM) method is based on a simple correlation between the rheological properties of concrete and the mortar of which it consists. The latter can be obtained experimentally by sieving fresh concrete with a 5 mm sieve or from a theoretical composition which gives the same properties as sieved mortar (Gołaszewski et al., 2016; Schwartzentrube & Catherine, 2000). The CEM formulation is deduced directly from the composition of an initial concrete formulated with a cement dosage of 350 kg/m3, a W/C ratio of 0.4, and a G/S ratio equal 1.46. The same constituents and the same dosages were kept, except for the gravel, and they were replaced with sand whose specific areas of grains is equal to the gravel removed. The specific areas of sand and gravel were calculated according to Schwartzentrube and Catherine (2000). A quantity of 0.5% superplasticizer (SP) was used in order to ensure 10 ± 1 cm slump to control the mortar (mortar with pure cement) in a standard environment. This slump is equivalent to 20 ± 1cm in the concrete, which can be classified in the consistency class of S4, as referenced by standard NF EN 206-1. To reduce the environmental impact and heat due to hydration, MK and MP were added as mineral additives to replace cement by mass with 5 to 20% of mortar in a binary system and 25 to 50% of mortar in a ternary system. Table 2 summarizes the proportions of the CEM.
Bio-remediation of cracks – a novel technique to self-heal cracks in the concrete
Published in European Journal of Environmental and Civil Engineering, 2023
C50/60 grade of concrete was prepared as per BS EN 206-1 (2000). The mix ratio was obtained as 1:1.42:2.73:0.4. Seven different types of concrete mixtures were prepared with B. subtilis and E. coli of three different cell concentrations of 101, 103 and 105 cells/ml each and one as a control mixture with no bacteria. The concrete mixtures prepared with 101, 103 and 105 cells/ml of B. subtilis were designated as B1, B2 and B3 and the concrete mixtures prepared with 101, 103 and 105 cells/ml of E. coli were designated as E1, E2, E3 and the concrete mixtures with no bacteria were designated as B0. Table 3 shows the quantities of raw materials for different concrete mixtures.
Evaluation of mechanical properties and structural behaviour of concrete pavements produced with virgin and recycled aggregates: an experimental and numerical study
Published in International Journal of Pavement Engineering, 2022
Onur Ozturk, Hasan Yildirim, Nilufer Ozyurt, Turan Ozturan
Control concrete mixture (CStC) was produced using 321.4 kg/m3 Portland cement, 128.6 kg/m3 GGBFS, 85.05 and 693.25 kg/m3 natural and crushed sand, respectively, 476.61 kg/m3 No-I and No-II crushed stone each and 212.14 kg/m3 water at a w/c of 0.50. The amount of each aggregate in the concrete mixture was determined according to the optimum aggregate grading curve constructed regarding the limitations recommended by TS 802, as shown in Figure 2. In line with the recommendation by Lee et al. (2015) for the optimum cement replacement ratio of GGBFS, 40% of cement, by weight, was replaced by GGBFS in the concrete mixture with a total cementitious material content of 450 kg/m3. The cement equivalence factor of 0.8 for GGBFS according to TS 13515 (2012) and TS EN 206-1 was considered to determine the water content in the concrete mixture. The control concrete was designed to have a compressive strength of 40–50 MPa. Four recycled aggregate concrete mixtures were produced by volume replacing the No-I and No-II crushed stone coarse aggregates in the control concrete by recycled aggregates, which were used as plain (RBA, RCA) and surface treated (TRBA, TRCA) by GGBFS slurry, as given in Table 1. A sufficient amount of superplasticiser (SP) was added to get a slump of 18 ± 2 cm.