centre for cement and concrete strength retention of ar...
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Centre for Cement and Concrete
Strength Retention of AR Glass Strength Retention of AR Glass Fibres in Alkali ExposureFibres in Alkali Exposure
Yanfei CheYanfei CheK. PilakoutasK. Pilakoutas
Centre for Cement and Concrete,Centre for Cement and Concrete,The University of SheffieldThe University of Sheffield
14th International GRC Congress14th International GRC CongressNov 2005, Hong KongNov 2005, Hong Kong
Centre for Cement and Concrete OutlineOutline
AimAimExperimental programmeExperimental programmeResultsResultsConclusionConclusion
Centre for Cement and Concrete AimAim
To examine the tensile strength retention of single To examine the tensile strength retention of single glass filaments and strands in different cement glass filaments and strands in different cement related alkali environmentrelated alkali environment
Centre for Cement and Concrete Experimental programmeExperimental programme
Weight lossWeight lossStrength retention Strength retention Single filament in saturated Single filament in saturated Ca(OH)Ca(OH)22 solutionsolutionStrands in saturated Strands in saturated Ca(OH)Ca(OH)22 solutionsolutionStrands in OPCStrands in OPC
sulfoaluminate cementsulfoaluminate cementChina rapid hardeningChina rapid hardeningChina low alkalinityChina low alkalinityUK productUK product
Centre for Cement and Concrete Strength retentionStrength retention
Mounting specimens -- filaments
20135
20 20
Super glueGlass filament
adhesive tape
10
Single filament: Plain A4 paper
Strand: chrome paper (non-ageing)
cellophane paper (ageing)
Centre for Cement and Concrete Strength retentionStrength retention
Mounting specimens -- strands
30200
20 20
Super glueglass strand
resin
10
grip area
20
gauge length
Centre for Cement and Concrete Strength retentionStrength retention
SIC test specimens -- cements
OPC China Rapid Hardening
China Low Alkalinity
UK Sulfoaluminate
Centre for Cement and Concrete Strength retentionStrength retention
80℃100%RH
100hrs
rubber sealant tape
SIC test specimens
Centre for Cement and Concrete Strength retentionStrength retention
Hounsfield universal test machineHounsfield universal test machine
Crosshead speed:
For single filaments: 0.52mm/minFor strands: 1mm/min
Centre for Cement and Concrete Strength retentionStrength retention
GripsGrips
For single filaments For strands
Centre for Cement and Concrete Strength retentionStrength retention
filament
0
0.05
0.1
0.15
0.2
0.25
0 0.1 0.2 0.3 0.4 0.5
Displacement(mm)
Load(N)
LoadLoad--displacement curvedisplacement curve
strand
05
101520253035
0 1 2 3 4
Displacement(mm)
Load(N)
Centre for Cement and Concrete Strength retentionStrength retention
Measurement of Cross-Sectional Area
Held at 80oC for 200 hours in saturated Ca(OH)2 solution
Filament separated from strand
Cam-Scan SEM
Centre for Cement and Concrete Strength retentionStrength retention
Measurement of Cross-Sectional Area
A=Wi
ρ
Centre for Cement and Concrete ResultsResults
Alkalinity of Ca(OH)2 and final weight loss
1.4112.3012.6312.6513.33
200 hours96 hours24 hours0 hour
Weight loss(%)
PH of Ca(OH)2
Centre for Cement and Concrete ResultsResults
Alkalinity of different solution
11.5*10.5*13.2913.33PH
RapidHardening
Cement
Low AlkalinityCement
OPCSaturated Ca(OH)2solution
* Zhang L, Su M and Wang Y. Development of the use of sulfo-and ferroaluminate cements in China. Advances in Cement Research, Jan.1999, 1:15-21
Centre for Cement and Concrete ResultsResults
Strength retention
58.1%52.4%56.4%36.5%82.7%30.3%Strength retention
UKRapidLowOPCCa(OH)2Ca(OH)2
StrandsSingle filaments
Variety
Centre for Cement and Concrete ConclusionConclusion
After the alkalinity exposure, fibre strands exhibit softer After the alkalinity exposure, fibre strands exhibit softer characteristics, it is believed that a substantial part of the wcharacteristics, it is believed that a substantial part of the weight eight loss is due to the damage to the sizing. loss is due to the damage to the sizing. AR glass fibre strands demonstrate 50% higher strength AR glass fibre strands demonstrate 50% higher strength retention in sulphoaluminate cements than in OPC retention in sulphoaluminate cements than in OPC fibre strands in saturated Ca(OH)2 showed much higher strength fibre strands in saturated Ca(OH)2 showed much higher strength retention than in OPC of similar alkalinity.retention than in OPC of similar alkalinity.