Preplaced aggregate concrete (PAC) is produced by grouting high workability cement
based grouts among the voids of compacted coarse aggregate mass. Because of its low
shrinkage, PAC has been used for many repair jobs like; tunnel lines, dams and bridge
piers. Moreover, it has been used for underwater construction.
Grout has a major effect on the properties of produced PAC and well defined grout
controls the properties of resulted PAC. The effect of types and amount of powder
materials, admixtures, sand and water content on the properties of fresh and hardened
grout for the production of PAC have been investigated. Tests on hardened grout and
PAC properties have also been carried out to investigate the most important effects. A
correlation between hardened properties of grout and PAC has also been analyzed.
Grout rheology using four different gradation sands at two different cement-sand and at
different w/c ratios ratios has been identified experimentally; no added chemical
admixtures or mineral additives had first employed, then superplasticizer (SP) was
added at 2% and 1%, and finally a combination of 1% SP and pulverized fuel ash (Pfa)
at 20% of the cement weight was employed for all mixes. Grout tests have included two
point workability tests by the Viskomat NT, flow time funnel test, Colcrete flow meter
test, and water bleeding test. After that, eighteen grout mixes with high workability were
produced using three different sands at three w/c ratios and two c/s ratios with 1% SP
and Pfa at 20% of the cement weight were designed. Eighteen hardened grout and PAC
then produced and their compressive strength and sorptivity were tested.
Grout rheology can be defined by the rheology of cement paste employed and the
internal distance between sand particles. The effect of sand surface texture on grout
rheology is important at very low internal distances. Fresh grout yield stress is the most
important property which gives the same degree of sensitivity for all grouts regardless
the material type and content used in the mix. There are strong relations between
compressive strength of grout and PAC, but less correlation between them in sorptivity
test because of the effect high quantity of coarse aggregate of PAC. Sorptivity of PAC is
low comparing with different kinds of concrete suggesting its advantage for underwater
construction. / Libyan High Education Ministry
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/5766 |
| Date | January 2012 |
| Creators | Ganaw, Abdelhamed I. |
| Contributors | Hughes, David C., Ashour, Ashraf |
| Publisher | University of Bradford, School of Engineering, Design and Technology |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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