ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowab... more ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowability and high cohesiveness at the same time, it is often necessary to provide a fairly large cement paste volume of up to 35%. Such a large cement paste volume would lead to high cement consumption, low dimensional stability and a high carbon footprint. This paper presents a study on the feasibility of reducing the cement paste volume by adding fillers to the concrete mix. Two types of fillers, namely, limestone fines (LF) and ground sand (GS), were used. Trial concrete mixes with various amounts of LF and GS added were produced for slump flow, passing ability, sieve segregation and compressive strength tests. The results revealed that although the addition of fillers would substantially increase the superplasticiser demand, it would allow the cement paste volume to be reduced to as low as 25% while still meeting the slump flow, passing ability and segregation resistance requirements of SCC.
Abstract Shrinkage is an important concern in concrete since it induces deformation and tensile s... more Abstract Shrinkage is an important concern in concrete since it induces deformation and tensile stress, which may finally lead to cracking, in structural concrete members. Prediction for shrinkage of concrete is therefore an essential step at the structural design stage for determining required preventive measures. Following this need, various models are developed for predicting shrinkage of concrete in design codes. Unfortunately, their common shortcoming is the limited applicability to common cement types only. Lately in concrete repair applications, Calcium Sulfoaluminate Cement (CSAC) is becoming more and more popularly used due to its well-known properties of rapid strength gain and relatively low shrinkage. Nonetheless, since little study has been done for its long term shrinkage performance beyond the age of 28 days or even 56 days, the previously developed shrinkage prediction models are not applicable for concrete incorporating CSAC, not to mention when it is blended with other binder materials such as Ordinary Portland Cement (OPC), Pulversized Fuel Ash (PFA) and Ground Granulated Blastfurnace Slag (GGBS). In this study, shrinkage measurements were conducted for a total of 20 concrete mixes with different binder combinations but the same total binder content of 420Â kg/cum of concrete and the same water to binder ratio of 0.45 for observing their shrinkage development trends at different ages up to 1 year. The GL2000 Model for shrinkage prediction given in ACI 209.2R-08 is adopted for comparing with the measured results. Different k factors to be put in the GL2000 Model for different binder materials are derived and verified with the shrinkage results.
For the production of self-consolidating concrete (SCC), in order to achieve high flowability and... more For the production of self-consolidating concrete (SCC), in order to achieve high flowability and high cohesiveness at the same time, it is often necessary to provide a fairly large cement paste volume of up to 35%. Such a large cement paste volume would lead to high cement consumption, low dimensional stability and a high carbon footprint. This paper presents a study on the feasibility of reducing the cement paste volume by adding fillers to the concrete mix. Two types of fillers, namely, limestone fines (LF) and ground sand (GS), were used. Trial concrete mixes with various amounts of LF and GS added were produced for slump flow, passing ability, sieve segregation and compressive strength tests. The results revealed that although the addition of fillers would substantially increase the superplasticiser demand, it would allow the cement paste volume to be reduced to as low as 25% while still meeting the slump flow, passing ability and segregation resistance requirements of SCC.
ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowab... more ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowability and high cohesiveness at the same time, it is often necessary to provide a fairly large cement paste volume of up to 35%. Such a large cement paste volume would lead to high cement consumption, low dimensional stability and a high carbon footprint. This paper presents a study on the feasibility of reducing the cement paste volume by adding fillers to the concrete mix. Two types of fillers, namely, limestone fines (LF) and ground sand (GS), were used. Trial concrete mixes with various amounts of LF and GS added were produced for slump flow, passing ability, sieve segregation and compressive strength tests. The results revealed that although the addition of fillers would substantially increase the superplasticiser demand, it would allow the cement paste volume to be reduced to as low as 25% while still meeting the slump flow, passing ability and segregation resistance requirements of SCC.
ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowab... more ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowability and high cohesiveness at the same time, it is often necessary to provide a fairly large cement paste volume of up to 35%. Such a large cement paste volume would lead to high cement consumption, low dimensional stability and a high carbon footprint. This paper presents a study on the feasibility of reducing the cement paste volume by adding fillers to the concrete mix. Two types of fillers, namely, limestone fines (LF) and ground sand (GS), were used. Trial concrete mixes with various amounts of LF and GS added were produced for slump flow, passing ability, sieve segregation and compressive strength tests. The results revealed that although the addition of fillers would substantially increase the superplasticiser demand, it would allow the cement paste volume to be reduced to as low as 25% while still meeting the slump flow, passing ability and segregation resistance requirements of SCC.
Abstract Shrinkage is an important concern in concrete since it induces deformation and tensile s... more Abstract Shrinkage is an important concern in concrete since it induces deformation and tensile stress, which may finally lead to cracking, in structural concrete members. Prediction for shrinkage of concrete is therefore an essential step at the structural design stage for determining required preventive measures. Following this need, various models are developed for predicting shrinkage of concrete in design codes. Unfortunately, their common shortcoming is the limited applicability to common cement types only. Lately in concrete repair applications, Calcium Sulfoaluminate Cement (CSAC) is becoming more and more popularly used due to its well-known properties of rapid strength gain and relatively low shrinkage. Nonetheless, since little study has been done for its long term shrinkage performance beyond the age of 28 days or even 56 days, the previously developed shrinkage prediction models are not applicable for concrete incorporating CSAC, not to mention when it is blended with other binder materials such as Ordinary Portland Cement (OPC), Pulversized Fuel Ash (PFA) and Ground Granulated Blastfurnace Slag (GGBS). In this study, shrinkage measurements were conducted for a total of 20 concrete mixes with different binder combinations but the same total binder content of 420Â kg/cum of concrete and the same water to binder ratio of 0.45 for observing their shrinkage development trends at different ages up to 1 year. The GL2000 Model for shrinkage prediction given in ACI 209.2R-08 is adopted for comparing with the measured results. Different k factors to be put in the GL2000 Model for different binder materials are derived and verified with the shrinkage results.
For the production of self-consolidating concrete (SCC), in order to achieve high flowability and... more For the production of self-consolidating concrete (SCC), in order to achieve high flowability and high cohesiveness at the same time, it is often necessary to provide a fairly large cement paste volume of up to 35%. Such a large cement paste volume would lead to high cement consumption, low dimensional stability and a high carbon footprint. This paper presents a study on the feasibility of reducing the cement paste volume by adding fillers to the concrete mix. Two types of fillers, namely, limestone fines (LF) and ground sand (GS), were used. Trial concrete mixes with various amounts of LF and GS added were produced for slump flow, passing ability, sieve segregation and compressive strength tests. The results revealed that although the addition of fillers would substantially increase the superplasticiser demand, it would allow the cement paste volume to be reduced to as low as 25% while still meeting the slump flow, passing ability and segregation resistance requirements of SCC.
ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowab... more ABSTRACT For the production of self-consolidating concrete (SCC), in order to achieve high flowability and high cohesiveness at the same time, it is often necessary to provide a fairly large cement paste volume of up to 35%. Such a large cement paste volume would lead to high cement consumption, low dimensional stability and a high carbon footprint. This paper presents a study on the feasibility of reducing the cement paste volume by adding fillers to the concrete mix. Two types of fillers, namely, limestone fines (LF) and ground sand (GS), were used. Trial concrete mixes with various amounts of LF and GS added were produced for slump flow, passing ability, sieve segregation and compressive strength tests. The results revealed that although the addition of fillers would substantially increase the superplasticiser demand, it would allow the cement paste volume to be reduced to as low as 25% while still meeting the slump flow, passing ability and segregation resistance requirements of SCC.
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