Obviously, the content of fillers in SCC affects the packing factor. SCC strength is provided by the frame of aggregates glued in the hardened state by cement paste, while the technological properties of mixtures are provided by cement paste in the fresh state. For example, to obtain self-compacting mixtures of class SF 1, the value of the ultimate shear stress should be, approximately, from 8.9 to 14 Pa, and for mixtures of class SF 2 from 8.7 to 10 Pa.Ī simplified method of the SCC composition design is proposed based on the condition of achieving the maximum coarse and fine aggregate packing factor PF. It is based on dependence of cement paste shear stress on the type and dosage of additives for cement of a certain chemical and mineralogical composition. On the other hand, a rather simple method for estimating the rheological characteristics of cement paste was proposed. However, the disadvantages of the method is, first of all, that not all ready-mixed concrete plants are equipped with necessary equipment to study cement pastes and mortars rheology, in particular by rotary viscometers. An advantage of this method is that it avoids repetition of similar time-consuming tests for the entire concrete mix. (i) The volume ratio between water and dispersed materials (cement, mineral admixture, and sand fractions smaller than 0.125 mm) from 0.80 to 1.10 (ii) Total content of dispersed materials from 160 to 240 liters (400–600 kg per cubic meter) (iii) Cement content of 350–450 kg/m3 (cement consumption over 500 kg/m3 can increase shrinkage and creep of concrete consumption less than 350 kg/m3 may be allowed only when using other fine mineral fillers or pozzolanic additives) (iv) Coarse aggregate content from 28 to 35% by the concrete mix volume (v) The water-cement ratio is assigned based on the requirements of EN 206-1 (usually the water demand does not exceed 200 l/m 3).Ī known method for the SCC design is based on the idea that at the first stage the cement paste and mortar are tested to determine the compatibility of superplasticizer, cement, fine aggregate, and pozzolanic additive, and at the second stage a test SCC mix is tested. In the first stage, the ratios between the components are obtained based on typical diapason ranges providing the standardized indicators of the SCC mix. įollowing the recommendations of the European Federation of Specialists Construction Chemicals and Concrete Systems, it is more appropriate to use concrete composition design to the original components ratio by volume and not by weight. However, the need to ensure high SCC mix workability, its durability over time, higher rate of strength growth, as well as high values of the entire set of concrete performance properties makes it difficult to justify its composition, which along with technological criteria should also ensure economic feasibility. Additionally, production technology of SCC has higher environmental parameters. This high-technological concrete allows energy saving and achieving high physical and mechanical characteristics of structures, especially thin-walled, densely reinforced, and complex ones. Introductionĭevelopment and implementation of effective superplasticizing additives in technological practice allowed production of self-compacting concrete (SCC). Optimization of SCC compositions using mathematical programming enables to obtain compositions with a lowest possible cost while providing a set of specified parameters. It is found that the nature of correlation dependences for SCC splitting and compression strengths when using the blast furnace slag and the superplasticizer is linear. Dependences for calculating SCC strength at 1, 7, and 28 days vs. The possibility of minimizing the cement consumption at optimal superplasticizer content and slag consumption of 100–120 kg/m 3 is shown. A significant effect of joint influence of superplasticizer and blast furnace slag is demonstrated. Optimal superplasticizer content, cement, and blast furnace slag consumptions are obtained from the viewpoint of minimum water demand and water-cement ratio, maximum self-compacting concrete mixture workability retention, and concrete strength. The paper deals with composition design of self-compacting concrete containing blast furnace granulated slag and polycarboxylate type superplasticizer in a wide range of concrete strength classes.
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