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Show me how After you enable Flash, refresh this webpage and the presentation should play. View by Category Toggle navigation. Products Sold on our sister site CrystalGraphics. Defined as Concrete that is able to flow and consolidate under its own weight, completely fill the formwork even in the presence of dense reinforcement, whilst maintaining homogeneity and without the need for any additional compaction.
Why it is needed? Concrete is a versatile material extensively used in construction applications throughout Self consolidating concrete ppt background world. Properly placed and cured concrete exhibits excellent compressive-force-resisting characteristics and engineers rely on it to perform in a myriad of situations.
The growing use of concrete in special architectural configurations and closely spaced reinforcing bars have made it very important to produce concrete that ensures proper filling ability, good structural performance and adequate durability. To help alleviate these concerns, Japanese researchers in the late s developed a concrete mixture that deformed under its own weight, thus filling around and encapsulating reinforcing steel without any mechanical consolidation.
As a result of the mix design, some properties of the hardened concrete can be different for SCC in comparison to normal vibrated concrete. Mix design criterions are mostly focused on the type and mixture proportions of the constituents.
Recently, a great native interest had been derived towards self-compacting concrete. Passing ability The ability of SCC to flow through openings approaching the size of the Self consolidating concrete ppt background coarse aggregate, such as the spaces between steel reinforcing bars, without segregation. Resistance to segregation The ability of SCC to remain homogeneous during transport, placing, and after placement.
The chemical process is due to the activation of the non-crystalline silica, by the calcium hydroxide produced from the hydrating cement to form secondary calcium silicate hydrate that also fills the pore spaces and further reduces the porosity.
Ease of placement results in cost savings through reduced equipment and labour requirement. Improves the quality, durability, and reliability of concrete structures due to better compaction and homogeneity of concrete. Faster construction Improves working conditions and productivity in construction industry. Greater freedom in design. More precise measurement and monitoring of the constituent materials. Requires more trial batches at laboratory as well as at ready-mixed concrete plants.
Costlier than conventional concrete based on concrete material cost exception to placement cost. The creation of durable concrete structures requires adequate compaction by skilled workers. Lack of uniform and complete compaction as the primary factor responsible for poor performance of concrete structures.
Okamura solved the issue of degrading quality of concrete construction due to lack of compaction by the employment of SCC which is independent of the quality of construction work.
Early s limited public knowledge about SCC, mainly in the Japanese language. The prototype of SCC was completed in Self consolidating concrete ppt background available materials in the market and is shown below. The coarse aggregate content in concrete is fixed at 50 of solid volume. The fine aggregate content is fixed at 40 of mortar volume. The water-powder ratio in volume is assumed as 0.
Nan Su et al. Packing Factor is used to determine the aggregate contents. The volume of fine aggregate is more than coarse aggregate. Soo-Duck Hwang et al. Later on by reducing the coarse aggregate from 45 to 37 and increasing fine aggregate contents from 40 to Hemant Sood et al.
Venkateswara Rao et al. The variables involved in the study are size of aggregate, dosage of fly ash and grade of concrete. Noticed that the fresh properties improved with increase in fly ash percentages.
This study illustrated that the optimum dosages of fly ash were 52 addition in case of standard grade SCC and it is 31 addition in case of high strength Self Compacting Concrete. In this study, the effect of replacing the cement, coarse aggregate and fine aggregate by limestone powder LP with silica fume SFquarry dust QD and clinkers respectively. At the same constant SP dosage 08 and mineral additives content 30LP showed the better workability. More than 8 replacement of cement by lime stone powder with silica "Self consolidating concrete ppt background" showed very significant reduction in the compressive strength.
The experimental result shows that the 15 fly ash mix gives the better strength characteristics as compared to the other fly ash mixes. CKD was used to replace the cement content by three various percentages 5, 10 and 15 and fly ash was kept as constant The compressive strength flexural strengths increases with increase in CKD contents up to Summary The literature review clearly indicates that the SCC having wider research scope and advantages in regard of performance, strength, quality and durability, etc.
Proper selection of materials, mix proportions based on various mix design methods, type of mineral and chemical admixtures, test methods and workability specifications are key concerns in Self consolidating concrete ppt background optimization and control testing "Self consolidating concrete ppt background" self compacting concrete. In most of the test data evaluated that the design methods developed to predict the characteristics of SCC is based on different mix proportions, materials and on experimental work.
In this literature Nan Su mix design shows that it is a simpler, easier for implementation and less time consuming and cost effective method. This method is based on the investigation work carried out in Taiwan. Hence in the present investigation work, Nan Su mix design was adopted for Indian conditions and examines the workability characteristics of SCC for different water binder ratios. The diameter of the concrete circle is a measure of the filling ability of concrete. The higher the slump flow value, the greater its ability to fill formwork under its own weight.
The funnel is filled with about 12 litres of concrete and the time taken for it to flow through the apparatus measured. After this the funnel can be refilled concrete and left for 5 minutes to settle. This test measured the ease of flow of the concrete shorter flow times indicate greater flowability. After 5 minutes of setting, segregation of concrete will show a less continuous flow with an increase in flow time.
The L-box consists of a chimney section and a channel section as described by Wu et al. With the L-box, the height of concrete in chimney, h1, the height of concrete in the channel section, h2, and the time for self-compacting concrete to reach mm from three steel bars, T, can be measured.
The U-box consists of a vessel that is divided by a middle wall in to two compartments. An opening with a sliding gate is fitted between the two sections. Reinforcing bars with nominal diameter of 13mm are installed at the gate with centre to centre spacing of 50mm.