skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Alkali-silica reaction and pore solution composition in mortars in sea water

Abstract

The promotion of expansion of mortars containing a reactive aggregate in 1N NaCl solution at 38 C was attributed to a rise of OH{sup {minus}} ion concentration in the pore solution in the mortars. However, it is ambiguous whether the promotion of expansion of mortars in sea water at a room temperature can be explained in the same way as in NaCl solution at an elevated temperature. This study aims at pursuing the expansion behavior of mortars containing a reactive aggregate relating it to their pore solution composition and the extent of alkali-silica reaction occurring within reactive grains. The alkali-silica reaction in mortars in sea water and 0.5 1N NaCl solution at 20 C appears to progress differently from that in mortars in 1N NaCl solution at an elevated temperature of 38 C. The promotion of expansion of mortars in sea water at 20 C was found to be responsible for an effect of Cl{sup {minus}} ions in the alkali-silica reaction at early stages of immersion. Only when OH{sup {minus}} ion concentration in the pore solution was relatively high, NaCl and sea water could accelerate the alkali-silica reaction in mortars at 20 C.

Authors:
;  [1]
  1. Kanazawa Univ., Ishikawa (Japan). Dept. of Civil Engineering
Publication Date:
OSTI Identifier:
417922
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cement and Concrete Research; Journal Volume: 26; Journal Issue: 12; Other Information: PBD: Dec 1996
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; MORTARS; EXPANSION; OFFSHORE PLATFORMS; MATERIALS; CHEMICAL REACTIONS; SILICA; AQUEOUS SOLUTIONS; SODIUM CHLORIDES; SEAWATER; TEMPERATURE DEPENDENCE; POROSITY; EXPERIMENTAL DATA

Citation Formats

Kawamura, Mitsunori, and Takeuchi, Katsunobu. Alkali-silica reaction and pore solution composition in mortars in sea water. United States: N. p., 1996. Web. doi:10.1016/S0008-8846(96)00178-0.
Kawamura, Mitsunori, & Takeuchi, Katsunobu. Alkali-silica reaction and pore solution composition in mortars in sea water. United States. doi:10.1016/S0008-8846(96)00178-0.
Kawamura, Mitsunori, and Takeuchi, Katsunobu. 1996. "Alkali-silica reaction and pore solution composition in mortars in sea water". United States. doi:10.1016/S0008-8846(96)00178-0.
@article{osti_417922,
title = {Alkali-silica reaction and pore solution composition in mortars in sea water},
author = {Kawamura, Mitsunori and Takeuchi, Katsunobu},
abstractNote = {The promotion of expansion of mortars containing a reactive aggregate in 1N NaCl solution at 38 C was attributed to a rise of OH{sup {minus}} ion concentration in the pore solution in the mortars. However, it is ambiguous whether the promotion of expansion of mortars in sea water at a room temperature can be explained in the same way as in NaCl solution at an elevated temperature. This study aims at pursuing the expansion behavior of mortars containing a reactive aggregate relating it to their pore solution composition and the extent of alkali-silica reaction occurring within reactive grains. The alkali-silica reaction in mortars in sea water and 0.5 1N NaCl solution at 20 C appears to progress differently from that in mortars in 1N NaCl solution at an elevated temperature of 38 C. The promotion of expansion of mortars in sea water at 20 C was found to be responsible for an effect of Cl{sup {minus}} ions in the alkali-silica reaction at early stages of immersion. Only when OH{sup {minus}} ion concentration in the pore solution was relatively high, NaCl and sea water could accelerate the alkali-silica reaction in mortars at 20 C.},
doi = {10.1016/S0008-8846(96)00178-0},
journal = {Cement and Concrete Research},
number = 12,
volume = 26,
place = {United States},
year = 1996,
month =
}
  • Pore solution chemistry (high pressure extraction method) of cement pastes made with two condensed silica fumes, three pulverized fly ashes and one ground granulated blast furnace slag was measured after 7, 28, 84, 182, 364 and 545 days of curing (38 C and 100% R.H.). Results were compared to expansions obtained for a 2 year time period in the CAN/CSA A23.2-14A Concrete Prism Method for concrete specimens made with two very alkali-silica reactive aggregates and tested at the same conditions and water/cement/SCM (supplementary cementing materials). A long-term threshold in alkali hydroxide concentration was observed around 0.65N, below which no significantmore » expansion occurred in corresponding concretes. The lower the SCM alkali content and the concrete alkali content as well, and the higher the SCM content, the easier this limit is satisfied.« less
  • The mechanical properties, pore size distribution, and extracted pore solution of fly ash-belite cement (FABC) mortars were studied for a period of 200 days. The influence of the calcination temperature, which ranged from 700 to 900 C, of the fly ash-belite cement was discussed. The evolution with hydration time of the pore size distribution was followed by mercury intrusion porosimetry, and the results correlated with those of flexural and compressive strength. The pore solution was expressed and analyzed at different times of hydration.
  • In this work, the relationship between the composition of pore solution in alkali-activated slag cement (AAS) pastes activated with different alkaline activator, and the composition and structure of the main reaction products, has been studied. Pore solution was extracted from hardened AAS pastes. The analysis of the liquids was performed through different techniques: Na, Mg and Al by atomic absorption (AA), Ca ions by ionic chromatography (IC) and Si by colorimetry; pH was also determined. The solid phases were analysed by XRD, FTIR, solid-state {sup 29}Si and {sup 27}Al NMR and BSE/EDX. The most significant changes in the ionic compositionmore » of the pore solution of the AAS pastes activated with waterglass take place between 3 and 24 h of reaction. These changes are due to the decrease of the Na content and mainly to the Si content. Results of {sup 29}Si MAS NMR and FTIR confirm that the activation process takes place with more intensity after 3 h (although at this age, Q{sup 2} units already exist). The pore solution of the AAS pastes activated with NaOH shows a different evolution to this of pastes activated with waterglass. The decrease of Na and Si contents progresses with time. The nature of the alkaline activator influences the structure and composition of the calcium silicate hydrate formed as a consequence of the alkaline activation of the slag. The characteristic of calcium silicate hydrate in AAS pastes activated with waterglass is characterised by a low structural order with a low Ca/Si ratio. Besides, in this paste, Q{sup 3} units are detected. The calcium silicate hydrate formed in the pastes activated with NaOH has a higher structural order (higher crystallinity) and contains more Al in its structure and a higher Ca/Si ratio than those obtained with waterglass.« less
  • Blended cement mortars with fixed workability and incorporating blast furnace slag and silica fume, were tested for compressive strength and mercury intrusion, with a view to comparing their performance with that of plain Portland cement mortar and/or slag-cement mortar. The obtained results showed that with high portions of slag and silica fume in the binding system, the mortars reached relatively satisfactory level of compressive strength and contributed to the significantly denser pore structure.
  • The reaction of Nevada opal with calcium hydroxide, potassium hydroxide and lithium hydroxide solutions was investigated. In addition, opal was exposed to a combined solution of these three hydroxides. The progress of the three reactions was followed using X-ray diffraction (XRD), {sup 29}Si nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). The XRD results indicated the presence of a low-angle peak exclusive to the lithium-based reactions. The NMR results suggested a change in the silicate structure in the presence of lithium. These techniques indicated that the reaction of the alkali with the opal starting material is inhibited and perhapsmore » stopped in the presence of lithium hydroxide. SEM revealed that the morphology of the reaction products on the surface of the reacted opal grains is markedly different invariably. It was concluded that evidence to support the theory of a protective layer exists and that the nature of the layer varies with ion type.« less