THE PERFORMANCE OF LIMESTONE CEMENTS WITH GGBS … · 2020. 1. 8. · Keywords: GGBS, sulfate, limestone cement 1. Introduction With concrete specifications in Ireland having rece

M. O’Connell, C. McNally & M. G. Richardson -1-

THE PERFORMANCE OF LIMESTONE CEMENTS WITH GGBS EXPOSED TO ELEVATED SULFATE ENVIRONMENTS

M. O’CONNELL, C. McNALLY & M.G. RICHARDSON

School of Architecture, Landscape and Civil Engineering, University College Dublin, Ireland

Secondary cementitious materials (SCMs) such as GGBS are being used in increasing quantities as a cement replacement and when used have been shown to possess an inherent sulfate resisting capability. Cements in Ireland have traditionally been supplied as CEM I but in recent years a shift in Irish concrete practice has led to the introduction of CEM II/A-L limestone cement as the primary cement available in this country. While the benefit of a reduced CO2 footprint through a reduced quantity of clinker has obvious environmental benefits, the change in cement chemistry must be urgently accounted for in concrete specification. This has particular importance when concrete is exposed to chemically aggressive conditions such as elevated sulfate environments.

In an attempt to evaluate the sulfate performance of CEM II/A-L cements with varying amounts of GGBS, twenty-four mortar prisms representing six different binder combinations were prepared and tested according to a modified ASTM C1012 method. Two of these sets consisted of a CEM I cement with 0% and 70% GGBS, three consisted of a CEM II/A-L cement with 0%, 50% and 70% GGBS as a cement replacement and the performance of a commonly used SRPC cement was also evaluated as a reference material.

Results show that for exposure in excess of one year to a 50g/l sodium sulfate (Na2SO4) solution the expansion of all specimens containing GGBS, irrespective of the cement used, was minimal and outperformed the SRPC reference cement. The results also show that CEM II/A-L cement appears to have an inherent sulfate-resisting capability and that this is further improved with the use of at least 50% GGBS as a cement replacement. The use of CEM II/A-L in the test programme showed an overall improved performance over specimens containing CEM I. Keywords: GGBS, sulfate, limestone cement

1. Introduction With concrete specifications in Ireland having recently shifted from CEM I to CEM II standard, a lack of data exists regarding the performance of GGBS and limestone cements in aggressive sulfate environments. A comparative analysis was carried out using a modified ASTM C1012 sulfate exposure test to examine the behaviour of these materials with sulfate-resisting cement used as a performance benchmark. Further analysis indicated that the diffusion of sulfate ions may form a key part of the degradation mechanism and that CEM II limestone cements may in fact possess an inherent sulfate resisting capability when compared CEM I cements. With GGBS also known to possess similar properties, the investigation attempts to confirm that CEM II with levels of GGBS greater that 50% can equal or exceed the performance of sulfate resisting cement.

2 M. O’Connell, C. McNally & M. G. Richardson

2. Experimental programme

Mortar prisms of dimensions 285mm x 25mm x 25mm were prepared with a mix according to EN 196-1 standard. Each mix contained 450g of binder, 1350g of CEN-Normsand (DIN EN 196-1) and 225g of water and produced four prisms. The specimens were placed in a moist air cabinet at 20˚C and demoulded after twenty-four hours. Following this they were then placed in a water bath at the same temperature and allowed to cure until twenty-eight days had elapsed. A modified ASTM C1012 standard was used to test the mortar prisms for change of length when exposed to a sulfate solution. The standard exposure solution used in this test method contains 50g of sodium sulfate (Na2SO4) per litre of distilled water. Each litre of the solution was prepared with 900ml of distilled water and mechanically stirred until fully dissolved. The solution was then topped up with distilled water until a volume of 1l was achieved. It was then placed into a standard domestic polyethylene container ensuring the quantity was sufficient to cover the prisms by a minimum of 5mm. The prisms were stored for in excess of one year with the solution refreshed on a monthly basis. Measurements were taken every four weeks. The readings consisted of taking an initial reference measurement for each prism and a standard reference bar prior to submersion in the sulfate solution then comparing them with readings of both the reference bar and mortar prism at the designated time intervals. The change of length of the prism from the initial reading is then calculated according to:

(1)

L = length change age ‘x’ (%); Lx = specimen comparator reading age ‘x’ – ref. bar comparator reading at age ‘x’; Li = initial comparator reading of specimen – ref. bar comparator reading at the same time; Lg = nominal gauge length (250mm used). The percentage change of length of each prism was measured to an accuracy of 0.001% and the average of the four test specimens was recorded.

Table 1 - Mortar mix designations

3. Experimental results Expansions were obtained for a 420-day period for all six mixes while measurements exist for some up to 532 days (Figure 1). There were some marked differences in visual deterioration of the mixes varying from corrosion related deposits and discoloration to cracking and warping of the specimens, or a combination of both. The severity of the visual deterioration corresponds well to the degree of expansion observed. With regard to the two most expansive mixes, both MA and MD can be seen to have some similarities but also some differences in the way they began to degrade. Common to both were the formation of longitudinal cracks along the length of the specimens as the first form of physical deterioration (Figure 2). For mix MD these became visible at approximately 140 days exposure and at 286 days for mix MA. With the latter however, this manifested initially in the form of the cracks being filled with a white substance (Figure 2).

M. O’Connell, C. McNally & M. G. Richardson

Longitudinal cracking along the length of the specimens was not an exclusive mechanism with radial cracking observed on one of the MA specimens along the boundary of the reference stud (Figure 3). One of the other visual distinctions notable deposits of a white substance occurring in blotches at random intervals on one of the prisms which can also part of the paste and were not sofscratching the surface. Generally however, the appearance of white deposits was less locally concentrated than in pattern throughout the prisms. This was applicable to all specimens and mixes after one year except those containing 70% GGBS as a cement replacement.mortar prisms appears to commence when approaching an expansion threshold of 0.030 0.035% (0.045% for MA, MD) and the observation has proven true for all specimens approaching this value. This phenomenon continued to progress culminating in a total loss of cohesion and when touched, the prism corners crumbled with ease. This extreme cahas thus far only applied to mix MD with expansion expansive mix (MA) after one year. At approximately the specimens of MD were observed with the first cracks perpendicular to the surface appearing

Figure 2 - Cracks visible along the edges of specimens (l


Figure 1 - Sulfate expansion tests

Longitudinal cracking along the length of the specimens was not an exclusive mechanism with radial cracking observed on one of the MA specimens along the boundary of the

. One of the other visual distinctions between MA and MD were s of a white substance occurring in blotches at random intervals on one of

also be seen in Figure 3. These deposits seemed to be an integral part of the paste and were not soft to touch, nor had they the ability to be remo

Generally however, the appearance of white deposits was less locally concentrated than in Figure 3 and consisted primarily of an intermittent speckled pattern throughout the prisms. This was applicable to all specimens and mixes after one year except those containing 70% GGBS as a cement replacement. The cracking of the mortar prisms appears to commence when approaching an expansion threshold of 0.030

0.045% for MA, MD) and the observation has proven true for all specimens approaching this value. This phenomenon continued to progress culminating in a total loss of cohesion and when touched, the prism corners crumbled with ease. This extreme cahas thus far only applied to mix MD with expansion readings 300% of the next most

mix (MA) after one year. At approximately 0.3% expansion (t = 12 monthsens of MD were observed becoming warped, slowly taking a ‘banana’ shape

the first cracks perpendicular to the surface appearing (Figure 4).

Cracks visible along the edges of specimens (left), white-filled (right)

-3-

Longitudinal cracking along the length of the specimens was not an exclusive mechanism with radial cracking observed on one of the MA specimens along the boundary of the

A and MD were s of a white substance occurring in blotches at random intervals on one of

. These deposits seemed to be an integral t to touch, nor had they the ability to be removed by

Generally however, the appearance of white deposits was less and consisted primarily of an intermittent speckled

pattern throughout the prisms. This was applicable to all specimens and mixes after one cracking of the

mortar prisms appears to commence when approaching an expansion threshold of 0.030 - 0.045% for MA, MD) and the observation has proven true for all specimens

approaching this value. This phenomenon continued to progress culminating in a total loss of cohesion and when touched, the prism corners crumbled with ease. This extreme case

readings 300% of the next most t = 12 months),

warped, slowly taking a ‘banana’ shape

filled (right)

4

Figure 3 - Radial cracking [enhanced

white blotches appearing on the surface of the prism (right)

Visually, both mixes MA and MD appear to have suffered the most. Cracking and spalling was widespread after one year forprominent feature for the attack on MA while MD exhibited almost exponential expansion. Mixes MB and MC, the CEM II limestone cements with 50% and 70% GGBS respectively, have shown comparatively little expansion. MB hminor discoloration while MC has shown no visual evidence of attack. The sulfate resisting cement specimens (SR) have been outperformed by all mortars containing GGBS either with CEM I or CEM II after one year. Visually it has begun to exhibithe same common degradation phenomenon when approaching the 0.030% expansion threshold, namely cracking,appearance (the latter, however, generally beginning to appear within eight weeks).

4. Effect of the addition of limestone The results have indicated that the CEM II limestone cement, as used here, appears to possess an inherent sulfate-resisting capabilityrecorded expansion readings are still very high but can be reduced faddition of 50% or 70% GGBS as a cement replacement. Existing research on the effect of limestone additions to cement has indicated widevarying from beneficial to detrimental 1998, Irassar et al., 2000). Nonetheless a common conclusion seems tupper limit of limestone additionsto vary between 15% and 20% This varying behaviour has been attributed to several possibilities amongst which are: the dilution effect of cement constituents, the influence of the level of Csystem and the level of calcium hydroxide (CH) in the hydrated cement paste. are clearly other issues regarding the reaction of limestone with both the cement paste and sulfate ions. Further consequences of its addition surroundpermeability, porosity and tortuosityby several authors (Hornain et al., 1995, Tsivilis et al., 2003, Pipilikaki et al., 2009)In the context of these parameters ialso increases with an increasing percentage of to its lack of pozzolanic properties (hence it cannot be considered a cementitious material).


enhanced in photo] around the reference studs (left) and

white blotches appearing on the surface of the prism (right)

Visually, both mixes MA and MD appear to have suffered the most. Cracking and spalling was widespread after one year for both with white deposits seemingly a prominent feature for the attack on MA while MD exhibited almost exponential expansion. Mixes MB and MC, the CEM II limestone cements with 50% and 70% GGBS respectively, have shown comparatively little expansion. MB has shown some minor discoloration while MC has shown no visual evidence of attack. The sulfate resisting cement specimens (SR) have been outperformed by all mortars containing GGBS either with CEM I or CEM II after one year. Visually it has begun to exhibithe same common degradation phenomenon when approaching the 0.030% – 0.035% expansion threshold, namely cracking, some minor spalling and a white speckled appearance (the latter, however, generally beginning to appear within eight weeks).

addition of limestone

The results have indicated that the CEM II limestone cement, as used here, appears to resisting capability relative to CEM I cement.

recorded expansion readings are still very high but can be reduced further by the of 50% or 70% GGBS as a cement replacement. Existing research on the

effect of limestone additions to cement has indicated wide-ranging consequences varying from beneficial to detrimental impacts on performance (González and Irassar,

. Nonetheless a common conclusion seems to centre on an of limestone additions that provide an improved resistance and this seems

to vary between 15% and 20% (Ramezanianpour et al., 2009, Irassar et al., 2005)This varying behaviour has been attributed to several possibilities amongst which are: the dilution effect of cement constituents, the influence of the level of C3A on the system and the level of calcium hydroxide (CH) in the hydrated cement paste.

regarding the reaction of limestone with both the cement paste onsequences of its addition surround its effect o

permeability, porosity and tortuosity and these are all topics that have been discussed (Hornain et al., 1995, Tsivilis et al., 2003, Pipilikaki et al., 2009)

In the context of these parameters it should also be noted that the effective w/c ratio also increases with an increasing percentage of limestone used which can be attrib

lack of pozzolanic properties (hence it cannot be considered a cementitious


around the reference studs (left) and

Visually, both mixes MA and MD appear to have suffered the most. Cracking and both with white deposits seemingly a

prominent feature for the attack on MA while MD exhibited almost exponential expansion. Mixes MB and MC, the CEM II limestone cements with 50% and 70%

as shown some minor discoloration while MC has shown no visual evidence of attack. The sulfate resisting cement specimens (SR) have been outperformed by all mortars containing GGBS either with CEM I or CEM II after one year. Visually it has begun to exhibit

0.035% spalling and a white speckled

appearance (the latter, however, generally beginning to appear within eight weeks).

The results have indicated that the CEM II limestone cement, as used here, appears to relative to CEM I cement. The

urther by the of 50% or 70% GGBS as a cement replacement. Existing research on the

ranging consequences (González and Irassar,

o centre on an that provide an improved resistance and this seems

(Ramezanianpour et al., 2009, Irassar et al., 2005). This varying behaviour has been attributed to several possibilities amongst which are:

A on the system and the level of calcium hydroxide (CH) in the hydrated cement paste. There

regarding the reaction of limestone with both the cement paste effect on

are all topics that have been discussed (Hornain et al., 1995, Tsivilis et al., 2003, Pipilikaki et al., 2009).

t should also be noted that the effective w/c ratio can be attributed

lack of pozzolanic properties (hence it cannot be considered a cementitious


Figure 4 - Perpendicular crack propagation in mix MD. Top left shows onset.

According to Gonzalez and Irassar (1998), the capillary porosity depends on the w/c ratio but also the hydration degree and thus this affects the overall porosity of the cement. Tsivilis et al. (2003) showed that a Portland limestone cement exhibilower water permeability values when compared to an ordinary Portland cement; they added however that permeability is not simply a function of porosity but size, distribution, shape, tortuosity, and continuity of the pores. Their tests werecarried out on specimens that contained a range of between 0% and 35% limestone. Pipilikaki et al. (2009) however conducted tests that showed Portland limestone cement containing 35% limestone had a higher porosity than an ordinary Portland cement. The authors then suggested that this mayturn contradict the findings ofhowever, that CEM II limestone cements have an absence of large capillariesto CEM I which may delay the ingress of sulfates and lower initial expansion but stress that the mechanism by which limestone affects the sulfate resistance of cement is far from being well understood.

Portland limestone cements suffer similar chemical reactions sulfate attack as ordinary Portland cements resulting primarily in the formation of gypsum and ettringite. The formation of thaumasite high level of carbonate in the systemduring cement hydration carbonate ions from the limestone compete with sulfate ions from gypsum to react with aluminate ions from Cmonosulfoaluminate and ettringite. Irassar et al. (2003) detailed the sequence of sulfate attack concluding that diffusion of sulfate ions is followed by calcium hydroxide leaching, ettringite formation, gypsum formation and depletion of CH. The latter stages involve the decalcification of CAs observed with CEM II limestone mix MAapplicable. There was an initial low level expansion detected with very little visual deterioration which could indicate the onset of ettringite or early gypsum formation. As the attack progressed white deposits began forming on the exterior of each prism, followed by a lack of cohesion and spalling at the edges, possibly indicating the


Perpendicular crack propagation in mix MD. Top left shows onset.

According to Gonzalez and Irassar (1998), the capillary porosity depends the hydration degree and thus this affects the overall porosity

of the cement. Tsivilis et al. (2003) showed that a Portland limestone cement exhibilower water permeability values when compared to an ordinary Portland cement; they added however that permeability is not simply a function of porosity but size, distribution, shape, tortuosity, and continuity of the pores. Their tests werecarried out on specimens that contained a range of between 0% and 35% limestone. Pipilikaki et al. (2009) however conducted tests that showed Portland limestone cement containing 35% limestone had a higher porosity than an ordinary Portland

thors then suggested that this may indicate a higher permeability and in turn contradict the findings of Tsivilis et al. (2003). They make the observation

limestone cements have an absence of large capillarieswhich may delay the ingress of sulfates and lower initial expansion but

stress that the mechanism by which limestone affects the sulfate resistance of cement understood.

Portland limestone cements suffer similar chemical reactions from a traditional sulfate attack as ordinary Portland cements resulting primarily in the formation of gypsum and ettringite. The formation of thaumasite may also be of concern given the high level of carbonate in the system. According to Gonzalez and Irasduring cement hydration carbonate ions from the limestone compete with sulfate ions from gypsum to react with aluminate ions from C3A forming monocarboaluminate, monosulfoaluminate and ettringite. Irassar et al. (2003) detailed the sequence of sulfate attack concluding that diffusion of sulfate ions is followed by calcium hydroxide leaching, ettringite formation, gypsum formation and depletion of CH. The latter stages involve the decalcification of C-S-H followed by thaumasite formation.

served with CEM II limestone mix MA some of these assumptions may be here was an initial low level expansion detected with very little visual

deterioration which could indicate the onset of ettringite or early gypsum formation. rogressed white deposits began forming on the exterior of each prism,

followed by a lack of cohesion and spalling at the edges, possibly indicating the

-5-

Perpendicular crack propagation in mix MD. Top left shows onset.

According to Gonzalez and Irassar (1998), the capillary porosity depends not only the hydration degree and thus this affects the overall porosity

of the cement. Tsivilis et al. (2003) showed that a Portland limestone cement exhibited lower water permeability values when compared to an ordinary Portland cement; they added however that permeability is not simply a function of porosity but also of the size, distribution, shape, tortuosity, and continuity of the pores. Their tests were carried out on specimens that contained a range of between 0% and 35% limestone. Pipilikaki et al. (2009) however conducted tests that showed Portland limestone cement containing 35% limestone had a higher porosity than an ordinary Portland

indicate a higher permeability and in Tsivilis et al. (2003). They make the observation

limestone cements have an absence of large capillaries relative which may delay the ingress of sulfates and lower initial expansion but

stress that the mechanism by which limestone affects the sulfate resistance of cement

from a traditional sulfate attack as ordinary Portland cements resulting primarily in the formation of

concern given the According to Gonzalez and Irassar (1998),

during cement hydration carbonate ions from the limestone compete with sulfate ions A forming monocarboaluminate,

monosulfoaluminate and ettringite. Irassar et al. (2003) detailed the sequence of a sulfate attack concluding that diffusion of sulfate ions is followed by calcium hydroxide leaching, ettringite formation, gypsum formation and depletion of CH. The

H followed by thaumasite formation. some of these assumptions may be

here was an initial low level expansion detected with very little visual deterioration which could indicate the onset of ettringite or early gypsum formation.

rogressed white deposits began forming on the exterior of each prism, followed by a lack of cohesion and spalling at the edges, possibly indicating the


decalcification of the C-S-H phase. Irassar et al. (2003) also describe corrosion of edges and corners and attribute it to gypsum formation in parallel veins to the sulfate attack front. As apparent in Figure 2, cracks/veins with a white deposit can be observed around the elapsed exposure time when the specimen began to shed some minor mortar particles.

5. Sulfate resisting capabilities of GGBS In examining the results of the experimental programme, it is clear that the addition of a relatively high percentage of GGBS to both CEM I and CEM II mortars has had a profound effect on their resistance to a 5% sodium sulfate solution. Both the CEM II mortars (MB and MC) have shown the least amount of expansion and visual deterioration while the CEMI I mortar with 70% GGBS (ME) has shown a resistance equalling SRPC for the majority of the exposure period but eventually exceeding it. The sulfate resisting capabilities of GGBS have been discussed on many occasions (BRE, 2003, Higgins and Crammond, 2003) with much of the benefit being attributed to a denser matrix, decreased permeability and a reduction in calcium hydroxide present in the hydrated system (Pavía and Condren, 2008, Al-Dulaijan et al., 2003, Osborne, 1999). Furthermore, with the formation of a secondary C-S-H phase attributable to the interaction between calcium hydroxide and GGBS, much of the alumina in the system becomes ‘locked up’ in this product and is not available to form ettringite during a sulfate attack (Gollop and Taylor, 1996). The author’s also claim that as the percentage replacement of cement with GGBS increases the proportion which reacts decreases and this limits the quantity of alumina released at high slag contents.

The combination of a reduction in calcium hydroxide, decreased permeability and the ‘locking up’ of potentially reactive alumina may account for the behaviour of the CEM I mortars but it is essential to investigate any further effects of CEM II cements with a limestone addition. The results presented above have indicated the potential increased benefit of using this with at least 50% GGBS as a cement replacement. As previously discussed, CEM II limestone cements have an absence of large capillaries relative to CEM I which may delay the ingress of sulfates (Pipilikaki et al., 2009). When combining this with the more impermeable matrix from GGBS cements, the opportunity for sulfates to interact with the cement compounds is being severely limited. Visually, all specimens containing GGBS have exhibited almost no evidence of a lack of cohesion from exposure to the sulfate solution. Researchers (Brown and Taylor, 1999) have attempted to account for this effect in limestone cements and have put forward a plausible explanation. With an increase in GGBS levels, there is also an increase in hydrated C-S-H in the system. Correspondingly, there is a decrease in the level of calcium hydroxide. Ettringite and gypsum preferentially obtain their calcium from this phase but in the absence of a sufficient quantity available, calcium from the C-S-H phase will serve as a source. This phase constitutes the primary binding capability of a cement matrix and its degradation leads to a major loss in cohesion. The author’s claim that by adding calcium carbonate (limestone) as an additive, this in turn will serve as the source of calcium for ettringite and gypsum thus preserving the integrity of the C-S-H phase.

M. O’Connell, C. McNally & M. G. Richardson -7-

6. Analysis of sulfate deterioration It has been observed that many concrete degradation mechanisms (i.e. carbonation, diffusion and chloride phenomena) have a time0.5 dependency (Richardson, 2002), thus by applying a similar approach to the obtained expansion data it can be seen that there is a strong proportional relationship between expansion of the mortar prisms and time0.5 (Figure 5). It may be claimed that simply plotting against time alone also produces a direct relationship, however by doing so one misses out on an important observation. Of the specimens that have exceeded an expansion of 0.05% or more (MA, MD, SR), there appears to be a divergence from the time0.5 proportionality at that point, as illustrated by Figure 5(r), coinciding with the onset of parallel cracking on the prisms surfaces. When simply plotted against time alone however, they merely continue to show a gradual expansion without any apparent differentiation in the curves.

Figure 5 – Time0.5 dependencies; deviations begin around expansions of 0.05% (right)

This figure of 0.05% may have significance in that it represents both the six month exposure limit for severe sulfate attack (>10g/l) as determined by the American Concrete Institute (ACI) for ASTM C1012 and the sixth month expansion limit for high sulfate resistance of Portland/slag combination cements as laid out in ASTM C989-06. The other three mortar mixes (MB, MC and ME) have not yet reached the 0.05% threshold and as such are still exhibiting a direct proportionality to time0.5 Figure 5(l). Of the mixes that have reached the level of expansion following which a divergence from time0.5

dependency is observed, there is clearly a common sequence of corrosion events. Given the time required to observe each specimen to failure in its entirety may require several years, one may hypothesise a sequence of events common to some, if not all, mixes based on those prisms in an advanced stage of corrosion. The degradation process appears to follow four distinct phases: Stage 1: A direct proportionality between expansion and time0.5 during which no cracking is visible, some surface blemishing may be apparent; Stage 2: This stage may represent a transition zone between 0.035% and 0.05% where some longitudinal crack propagation may be observed and the specimen may or may not continue to exhibit a time0.5 dependency; Stage 3: Expansion>0.05%, divergence from time0.5 dependency is observed and longitudinal crack propagation becomes more widespread. Radial cracking may also begin slightly before or after the 0.05% level; Stage 4: Expansion 0.3%, the specimen begins to warp, extensive longitudinal cracking is visible and bulging around the reference studs reaches a critical level. Perpendicular cracking may also become visible. While this sequence of events may be relevant for the non-GGBS specimens (as these are the most advanced stage samples), those that do contain GGBS cannot be assumed to perform in a similar behavior although expansions and observations made to date do not suggest that this will be the case.


7. Conclusions

• The results confirm the CEM II-A/L limestone cement used in this analysis (with limestone additions not exceeding 7%) appears to possess an inherent sulfate-resisting capability relative to CEM I cement. Limestone additions exceeding 15% however, may not be beneficial.

• The inclusion of at least 50% GGBS as a cement replacement further enhances the sulfate resistance of both CEM I and CEM II cements.

• The expansion of specimens up to 0.05% appears to be dependent on time0.5. This may confirm that diffusion [of sulfate ions] initially governs the degradation process. Subsequent expansion may depend on the extent of surface cracking and degree of corrosion products formed.

References Al-Dulaijan, SU, Maslehuddin, M, Al-Zahrani, MM, Sharif, AM, Shameem, M & Ibrahim, M (2003) Sulfate resistance of plain and blended cements exposed to varying concentrations of sodium sulfate. Cement and Concrete Composites, 25, 429-437. BRE (2003) BRE Special Digest 1, Concrete In Aggressive Ground. . Part 1: Assessing the Aggressive Chemical Environment. 2nd Ed, BRE Ltd. Brown, PW & Taylor, HFW (1999) The role of ettringite in external sulfate attack. In: Marchand, J. & Skalny, J. (Eds.) Proc. Seminar Sulfate Attack Mechanisms. Quebec. Gollop, RS & Taylor, HFW (1996) Microstructural and microanalytical studies of sulfate attack: Comparison of different slag blends. Cement and Concrete Research, 26, 1029-1044. González, MA & Irassar, EF (1998) Effect of limestone filler on the sulfate resistance of low C3A Portland cement. Cement and Concrete Research, 28, 1655-1667. Higgins, DD & Crammond, NJ (2003) Resistance of concrete containing GGBS to the thaumasite form of sulfate attack. Cement and Concrete Composites, 25, 921-929. Hornain, H, Marchand, J, Duhot, V & Moranville-Regourd, M (1995) Diffusion of chloride ions in limestone filler blended cement pastes and mortars. Cement and Concrete Research, 25, 1667-1678. Irassar, EF, Bonavetti, VL, Trezza, MA & González, MA (2005) Thaumasite formation in limestone filler cements exposed to sodium sulphate solution at 20°C. Cement and Concrete Composites, 27, 77-84. Irassar, EF, González, M & Rahhal, V (2000) Sulfate resistance of type V cements with limestone filler and Pozzolana. Cement and Concrete Composites, 22, 361-368. Osborne, GJ (1999) Durability of Portland blast-furnace slag cement concrete. Cement and Concrete Composites, 21, 11-21. Pavía, S & Condren, E (2008) Study of the durability of OPC vs GGBS concrete on exposure to silage effluent. Journal of Materials in Civil Engineering, 20, 313-320. Pipilikaki, P, Katsioti, M & Gallias, JL (2009) Performance of limestone cement mortars in high sulfate environment. Construction Building Materials, 23, 1042-1049. Ramezanianpour, AA, Ghiasvand, E, Nickseresht, I, Mahdikhani, M & Moodi, F (2009) Influence of various amounts of limestone powder on performance of Portland limestone cement concretes. Cement and Concrete Composites, 31, 715-720. Richardson, MG (2002) Fundamentals of Durable Reinforced Concrete, London, Spon Press. Tsivilis, S, Tsantilas, J, Kakali, G, Chaniotakis, E & Sakellariou, A (2003) The permeability of Portland limestone cement concrete. Cement and Concrete Research, 33, 1465-1471.

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THE PERFORMANCE OF LIMESTONE CEMENTS WITH GGBS … · 2020. 1. 8. · Keywords: GGBS, sulfate, limestone cement 1. Introduction With concrete specifications in Ireland having rece