AECOM siphokuhle.dlamini@aecom.com AFI Consult banie@afri-infra.com Alake Consulting Engineers lunga@alakeconsulting.com ARRB Systems info@arrbsystemssa.com Asla Construction (Pty) Ltd johanv@asla.co.za BMK Group brian@bmkgroup.co.za Bosch Projects (Pty) Ltd mail@boschprojects.co.za BVI Consulting Engineers marketing@bviho.co.za CCG puhumudzo@ccgsytems.co.za / info@ccgsystems.co.za Corrosion Institute of Southern Africa secretary@corrosioninstitute.org.za Dlamindlovu Consulting Engineers & Project Managers info@dlami-ndlovu.co.za EFG Engineers eric@efgeng.co.za Elster Kent Metering Mark.Shamley@Honeywell.com EMS Solutions paul@emssolutions.co.za ERWAT mail@erwat.co.za ESCONGWENI BPH ENGINEERS (PTY) LTD info@escbph.co.za Gabion Baskets mail@gabionbaskets.co.za GIBB marketing@gibb.co.za GIGSA secretary@gigsa.org GLS Consulting info@gls.co.za Gorman Rupp Cordeiro@gormanrupp.co.za Gudunkomo Investments & Consulting info@gudunkomo.co.za Hatch Africa (Pty) Ltd info@hatch.co.za HB Glass Filter Media info@hardybulkinglass.com Herrenknecht schiewe.helene@herrenknecht.de Huber Technology cs@hubersa.com Hydro-comp Enterprises info@edams.co.za Infrachamps Consulting info@infrachamps.co.za INFRATEC info@infratec.co.za IQHINA Consulting Engineers & Project Managers info@iqhina.co.za iX engineers (Pty) Ltd hans.k@ixengineers.co.za JBFE Consulting (Pty) Ltd issie@jbfe.co.za JG Afrika DennyC@jgafrika.com KABE Consulting Engineers info@kabe.co.za Kago Consulting Engineers kagocon@kago.co.za Kantey & Templer (K&T) Consulting Engineers ccherry@ct.kanteys.co.za Kitso Botlhale Consulting Engineers info@kitsobce.co.za KSB Pumps and Valves (Pty) Ltd salesza@ksb.com KUREMA Engineering (Pty) Ltd info@kurema.co.za Lektratek Water general@lwt.co.za Loshini Projects muzi@loshini.co.za Makhaotse Narasimulu & Associates mmakhaotse@mna-sa.co.za Mariswe (Pty) Ltd neshniec@mariswe.com Martin & East gbyron@martin-east.co.za M & C Consulting Engineers (Pty) Ltd info@mcconsulting.co.za Mhiduve adminpotch@mhiduve.co.za MPAMOT (PTY) LTD mpumem@mpamot.com Mvubu Consulting & Project Managers miranda@mvubu.net Nyeleti Consulting naidoot@nyeleti.co.za Odour Engineering Systems mathewc@oes.co.za Prociv Consulting & Projects Management amarunga@prociv.co.za Rainbow Reservoirs quin@rainbowres.com Re-Solve Consulting (Pty) Ltd maura@re-solve.co.za Ribicon Consulting Group (Pty) Ltd info@ribicon.co.za Royal HaskoningDHV francisg@rhdv.com SABITA info@sabita.co.za SAFRIPOL mberry@safripol.com SAGI annette@sagi.co.za SALGA info@salga.org.za SAPPMA admin@sappma.co.za / willem@sappma.co.za SARF administrator@sarf.org.za.co.za SBS Water Systems marketing@sbstanks.co.za Silulumanzi Antoinette.Diphoko@silulumanzi.com Siroccon International (Pty) Ltd admin@siroccon.co.za SiVEST SA info@sivest.co.za Sizabantu Piping Systems (Pty) Ltd proudly@sizabantu.com Siza Water (RF) Pty Ltd PA@sizawater.com Sky High Consulting Engineers (Pty) Ltd info@shconsultong.co.za SKYV Consulting Engineers (Pty) Ltd kamesh@skyv.co.za Smartlock jp.alkema@smartlock.net SMEC capetown@smec.com Southern African Society for Trenchless Technology director@sasst.org.za SRK Consulting jomar@srk.co.za Star Of Life Emergency Trading CC admin@staroflife.co.za TPA Consulting roger@tpa.co.za V3 Consulting Engineers (Pty) Ltd info@v3consulting.co.za VIP Consulting Engineers esme@vipconsulting.co.za VNA info@vnac.co.za Water Institute of Southern Africa wisa@wisa.org.za Wam Technology CC support@wamsys.co.za Wilo South Africa marketingsa@wilo.co.za WRCON ben@wrcon.co.za WRP ronniem@wrp.co.za Zutari Rashree.Maharaj@Zutari.com
CEMENT & CONCRETE
Kariba Dam rehabilitation project progresses
T
he stabilisation and reshaping of the plunge pool at the foot of Kariba Dam’s 138 m high wall is using vast quantities of concrete in a range of applications. “Among the first challenges we faced was in the construction of piers for the temporary coffer dam, where concrete had to be poured underwater to create a foundation,” says Martie Coulson of Mart Martie Coulson, director at Mart Solutions, Chryso Southern Africa’s Solutions, with Gilles Mouquet from Razel Bec Zambian distributor. Mart Solutions has been one of the key suppliers of construction chemicals to main contractor Razel-Bec since the beginning of the project. “Difficulties in finding bedrock for piers 7, 8 and 9 – as well as for the dam’s right bank – meant that 22 000 m3 of concrete had to be placed underwater,” Coulson explains. This arduous process – which took six months and was completed in September 2022 – involved pumping concrete to a depth of 25 m, with divers handling the 125 mm diameter pipe to place the concrete. Adding to the complexity was the movement of water from Zimbabwe’s nearby hydro-electric turbine outlet. “This raised the risk of the cement being washed out of the mix, leaving the aggregate behind, as well as further reducing visibility for the divers. The Chryso Aquabeton product played a critical role as an anti-washout admixture that increases the cohesion of the concrete mix,” she explains, adding that this allowed the placement of a concrete base for the three piers, measuring some 15 m wide and 20 m deep.
Repairing a rock fault Another important aspect of the project is repairing a fault in the rock at the foot of the Kariba Dam wall. Here, some 7 071 m3 of specialised concrete will be used for the large 90 m high, 45 m wide and 2.5 m thick wall, which will be built in front of the fault as a protective shield. This will be fixed onto the 12 m long, 40 mm diameter anchors in the wall, which Kariba Dam before and after placement of the piers will in turn be secured 10 m into the rock. A combination of Chryso Omega 162 and Chryso Fluid Optima 206 will be used in conjunction with densified silica fume and fly ash in the concrete mix for the wall to assist in preventing the temperature rise in the concrete during placement and to avoid cracking. This is important due to the high ambient temperatures of up to 40°C.
IMIESA April 2023
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