Concrete compressive strength

A minimum concrete compressive strength of 3,000 psi (20.7 MPa) should be used to reduce the probability of shear failures. A value of 4000 psi (27.6 MPa) is preferred. 

Physical properties of CSA-contaming concretes (compressive strength, creep, modulus of elasticity and durability) are comparable to those of corresponding Portland cement concretes, especially when CSA is used at dosages of 8-11%. When the dosage exceeds the ranges mentioned above and no restraint is provided either internally (by reinforcement) or... 

One can see that epoxy polymer concrete exhibits higher compressive strength, with values ranging from 3.8-4.3 times higher than commercial concrete. Compressive strength of this PC shows an increase of 1.5 times when glass fibers are added to the epoxy resin matrix and 2.0 times with the use of carbon fibers [8],... 

Aggregates are natural or artificial materials with particles of size and shape suitable for the production of concrete. Normally, aggregates occupy a high fraction of the volume of concrete (60-85 %). They allow a reduction in the amount of cement paste (and thus a reduction in both the cost of concrete and the consequences of heat of hydration, drying shrinkage and creep) and they contribute to the mechanical properties of concrete (compressive strength, elastic modulus, wear resistance, etc.). 

Figure 10. Influence of SBR polymer additive onto concrete compressive strength after 7 and 28...

Fig. 10.3 Abrasion resistance as a function of concrete compressive strength, (according to [23])...

Concrete compressive strength standard values feu (MPa) Steel type Steel yield strength fu (MPa) Ultimate strength steel fu (MPa)... 

As described in ASTM C1074 (2010), in order to develop concrete maturity curve, standard compressive strength specimens need to be cast, cured, and tested while continually recording the temperature of the concrete over time. Based on the recorded concrete temperature, the time-temperature factor can be calculated. A correlation is then made between the tested concrete compressive strength and the measured time-temperature factor to develop the concrete maturity curve. Note that the developed curve is only applicable to the tested concrete mix. 

In the absence of a concrete maturity test, a concrete maturity curve can be estimated using the results of concrete compressive strengths at various ages by performing a heat transfer analysis for a concrete cylinder cured under laboratory condition. The methodology for the heat transfer analysis of the lab samples is the same as previously discussed. Provided that the parameters used in the heat transfer analysis are representative of the concrete mix. 

Tabie 2. Predicted concrete compressive strength across the iining thickness... 

Giri Venkiteela, Sun Zhihui, Najm Husam. 2013. Prediction of Early Age Normal Concrete Compressive Strength Based on Dynamic Shear Modulus Measurements. Journal of Materials in Civil Engineering, 25(1) 3(C38. 

Concrete Compressive strength (MPa) Splitting tensile strength (MPa)... 

Figure 3 shows a generic reinforced concrete portal frame, for which the intervening variables considered, with their corresponding bounds, were number of stories NS = 3 to 10 number of bays NB = 1 to 4 bay span XL = 300 to 600 cm (all equal) mass per unit length for each story m = 2.15 x 10 to 4 x 10 KNs /cm characteristic concrete compressive strength = 20 to 40 MPa beam width bh = 15 to 30 cm ... 

The relation between compressive strength of concrete and quality of ITZ was studied by Darwin (1995) on the basis of experimental results and FEM calculations. His conclusions were that the ITZ has an appreciable influence, but the role of the properties of the cement matrix and aggregate and non-homogeneous structure of concrete are much more important. Goldman and Bentur (1993) suggested, after tests with SF and carbon black as an inert microfiller, that the increase of concrete compressive strength was due to increased density of the ITZ by the addition of SF. 

Table 13.3 Evolution of cement concrete compressive strength /jg...

In a t5 ical concrete mixing process, a large amoimt of water is added to increase flowability of the concrete (23). However, a water overdose lowers concrete compression strength and adversely affects other properties. In contrast, a lack of water causes concrete slump and deterioration, which is harmful to a construction process. Many chemical additives have been described to improve the concrete flowability without the need for increasing the amount of water. 

Shear strength contribution carried by concrete depends on concrete compressive strength, (Q shear span, Ly), section depth, (d) axial load, (P) and gross area section, (Ag), while shear strength contribution carried by reinforcements depends on transverse reinforcement area (Ajv ) within a spacing (s) in the loading direction. 

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