Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/30295
Title: Glass Sand Concrete and "Sandless Concrete"
Authors: DU HONGJIAN
Keywords: concrete, sand, sustainability, recycling, waste glass, alkali-silica reaction
Issue Date: 17-Aug-2011
Citation: DU HONGJIAN (2011-08-17). Glass Sand Concrete and "Sandless Concrete". ScholarBank@NUS Repository.
Abstract: Concrete is one of the most widely used construction materials, with annual global consumption exceeding one cubic meter per capita. Recently, there has been an increasing motivation in the study of sustainable concrete, as a result of awareness of environmental degradation, resource depletion and global warming. This research work examines two types of sustainable concrete, that is, glass sand concrete and ?sandless concrete?, aimed at increasing concrete sustainability with respect to the use of fine aggregates. In glass sand concrete, the natural sand is replaced by recycled waste glass sand. Major properties were investigated for cement-based mortar and concrete containing glass sand. All the mortar and concrete properties were found to be not harmfully affected, even at 100 % sand replacement. Instead, finer glass particles could enhance the concrete properties, such as strength and impermeability, due to pozzolanic reaction. Emphasis is on alkali-silica reaction (ASR) in glass sand mortar and concrete. The influence of glass color, content and particle size on ASR was thoroughly examined. It was found that glass sand with a size between 1.18 and 2.36 mm, regardless of color, would exhibit the highest ASR expansion. Different ASR mitigation methods, including cement replacement by supplementary cementitious materials (SCM), and addition of fiber reinforcement and lithium compounds, have also been examined. It is recommended that the combined use of fly ash or slag would significantly restrain ASR expansion. In ?sandless concrete?, the sand is totally eliminated and replaced by the other ingredients, that is, coarse aggregates, cement and water. Fly ash, up to 50% replacement, is used as cement alternative to avoid the high cement content in ?sandless concrete?. Mix design is achieved by two different approaches: (a) based on mix design of no-fines concrete; and (b) based on coarse aggregate packing and excess paste theory. Diverse properties, in both plastic and hardened states, were studied. From the results, ?sandless concrete? was found to show comparable characteristics as normal concrete, while its workability could be further improved. In addition, the durability of ?sandless concrete? with fly ash is substantially improved because of the densified micro-structure. Also, the mix design for ?sandless concrete? could be further optimized.
URI: http://scholarbank.nus.edu.sg/handle/10635/30295
Appears in Collections:Ph.D Theses (Open)

Show full item record
Files in This Item:
File Description SizeFormatAccess SettingsVersion 
DuH.pdf7.29 MBAdobe PDF

OPEN

NoneView/Download

Page view(s)

626
checked on Dec 16, 2018

Download(s)

742
checked on Dec 16, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.