by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
Concrete In Australia : December 2013
Concrete in Australia Vol 39 No 4 33 chemistry, the LF-SCC technology has been successfully tested at lab scale and plant scale prior to undertaking some significant projects with the proof of concept in place. Similar comparisons between TVC (vibrated for compaction) and LF- SCC at similar cementitious contents have shown reduction in manpower and vibration with higher productivity. Application example 3 Work summary: • Demonstration in partnership with leading ready mix producer in Singapore to show the time and labour savings of LF-SCC in comparison to TVC. Table 7 provides the basic mix details of comparison between TVC and LF-SCC. LF -SCC 1 mix has the same cementitious binder as the TVC mix while LF-SCC 2 has a reduction in cementitious binder content. Table 8 provides the comparison of fresh and hardened concrete properties of TVC and LF-SCC 1 and LF SCC 2. In concrete mixes LF-SCC 1 and LF-SCC 2 an innovative tailor-made polycarboxylate ether (PCE) based high range water reducer incorporating a unique viscosity modifier was used. No bleeding and segregation was observed. The time of com- pletion of the panel cast by three people (including vibration) was 5'05" while LF-SCC 1 was measured at 1'40" with one person (without vibration) as seen in Figures 10 and 11. It may be noted that the above demonstration was one of the first steps towards implementing this commercially on a few projects as a productivity improvement drive. One such example is the 18 storied condominium Cairnhill Rise in Singapore where LF-SCC had both qualitative and quantitative impacts as shown in Table 9. A detailed study was completed for the impact of time, manpower and equipment (including tower crane and concrete pumps). LF-SCC was used at the 3rd, 9th and 16th storeys while TVC was used at the 4th, 10th and 17th storeys. Another scenario was while concreting retaining walls, pile caps, basement beam and slab columns, and lift walls, as well as gable end walls whereby TVC was used till 1900h and LF-SCC was used after 1900h. Type Cement Slag (GGBS) Washed Copper Slag (WCS) Fine Aggregate Coarse Aggregate W/B Admixture Dosage (% by weight of cementitious) TVC 195 195 430 430 980 0.44 Water reducer retarder (0.5%) High range water reducer (0.5%) LF-SCC 1 195 195 505 505 835 0.44 Tailor made high range water reducer (1.4%) LF-SCC 2 185 185 515 515 850 0.44 Tailor made high ranger water reducer (1.7%) Table 7: Mix details of TVC and LF-SCC (all quantities in kg/m3). Table 8: Fresh and hardened concrete results. Slump / flow (in mm) Compressive Strengths (MPa) Initial 60 min 120 min 3 day 7 day 28 day TVC 140/– 100/– – 23.2 40.8 60.4 SDC 1 265 / 600 265 / 600 245 / 570 23.7 41.5 64.4 SDC 2 255 / 610 250 / 595 255 / 540 21.6 38.0 60.3 Figure 7: Placing LF-SCC by bucket. Figure 8: Placement. Figure 9: Finishing. 29-35 Kar.indd 33 29-35 Kar.indd 33 25/11/13 2:56 PM 25/11/13 2:56 PM