THE USE OF SUPPLEMENTARY CEMENTING MATERIALS IN THE MANIPULATION OF MIX WATER TRANSPORT IN MORTAR-MASONRY SYSTEMS

  • Yusuf Ozturk

Student thesis: Master of Philosophy

Abstract

Desorptivity, R, defines the water retaining ability of mortars in the freshly-mixed wet state. Sorptivity, S, defines the liquid absorption ability of a porous substrate such as brick, stone or concrete block by capillarity. Transfer sorptivity, A, is a function of both sorptivity and desorptivity and defines the ability of a porous substrate material such as brick to withdraw water from a freshly mixed wet mortar. The purpose of this thesis is an investigation of the possible role of supplementary cementing materials (SCMs) on the water retaining ability of hydrated lime (CL90) and Portland cement (PC) mortars. The SCMs investigated in this thesis were fly ash (FA), ground granulated blast-furnace slag (GGBS), silica fume (SF) and metakaolin (MK). Desorptivity is determined by a modified American Petroleum Institute pressure cell. A new experimental method has been developed to measure the sorptivity of high suction materials (e.g. Cyprus sandstone). The results show that the very water retaining CL90 mortars become progressively more water releasing with increased volume fraction replacement levels of both GGBS and FA. The presence of 50% FA in CL90 mortars causes a dramatic increase in desorptivity which is quantitatively equivalent to the most water releasing PC mortars. On the other hand, the very water releasing PC mortars become more water retaining with the addition of SF. It is concluded that desorptivity and hence transfer sorptivity increases as the volume fraction of GGBS and FA increases in CL 90 mortars and decreases with increased volume fraction addition of SF in PC mortars. Since the time taken to dewater a mortar joint (tdw) is inversely proportional to the transfer sorptivity, tdw is also dramatically altered by the addition of SCMs to both CL90 and PC mortars.
Date of Award31 Dec 2011
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorMoira Wilson (Supervisor)

Keywords

  • manipulation
  • supplementary cementing materials
  • desorptivity
  • sorptivity
  • transfer sorptivity
  • mortar
  • masonry
  • water retaining ability

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