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A new patented lightweight aggregates is tested. This type is given the name Flashag. The only solid raw material used to manufacture these aggregates is fly ash. The aggregates are sintered but not pelletized and the process is easy and... more
A new patented lightweight aggregates is tested. This type is given the name Flashag. The only solid raw material used to manufacture these aggregates is fly ash. The aggregates are sintered but not pelletized and the process is easy and inexpensive. This paper describes these patented aggregates and compares them with other lightweight and normal-weight aggregates that are used for
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Bricks whose solid ingredient is 100% fly ash have been manufactured. The manufacturing process uses techniques and equipment similar to those used in clay brick factories. The bricks produced were about 28% lighter than clay bricks. The... more
Bricks whose solid ingredient is 100% fly ash have been manufactured. The manufacturing process uses techniques and equipment similar to those used in clay brick factories. The bricks produced were about 28% lighter than clay bricks. The bricks manufactured from fly ash possessed compressive strength higher than 40 MPa. This exceeds some of the best of load carrying clay bricks
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Mercury intrusion porosimetry was performed for aggregates used for concrete in Kuwait. The curves which were established helped to identify the types of rocks used. Microstructural flows in the form of pores whose diameter is larger than... more
Mercury intrusion porosimetry was performed for aggregates used for concrete in Kuwait. The curves which were established helped to identify the types of rocks used. Microstructural flows in the form of pores whose diameter is larger than 100 nm were associated with certain identifiable rocks. Such pores are considered as a source of weakness for concrete and as a factor which adversely affects its durability.
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The effect of replacing cement by pozzolanic materials was investigated. This was done by a systematic increase in pozzolanic material inclusion, and was evaluated using the Rapid Chloride Permeability Test. The materials used were fly... more
The effect of replacing cement by pozzolanic materials was investigated. This was done by a systematic increase in pozzolanic material inclusion, and was evaluated using the Rapid Chloride Permeability Test. The materials used were fly ash, blast furnace slag (BFS), and ...
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ABSTRACT This paper examines the practicality and suitability of high proportion replacement of cement by class F fly ash. Binary and ternary blends of fly ash/Portland cement and fly ash/silica fume/Portland cement, were tested. The... more
ABSTRACT This paper examines the practicality and suitability of high proportion replacement of cement by class F fly ash. Binary and ternary blends of fly ash/Portland cement and fly ash/silica fume/Portland cement, were tested. The investigation focussed on the realistic conditions of concrete making on site and the effects on the mechanical aspects as well as the consequences on corrosion of reinforcement.It has been found that class F fly ash may replace 50% of the Portland cement and at the same time result in improving resistance to chloride initiated corrosion. Such replacement however, may significantly reduce the values of the mechanical properties. Nevertheless, such concrete is considered a high performance concrete. The authors therefore suggest that the mechanical and durability characteristics of concretes may be assigned numerical Performance Index values. These values may provide the means for making informed decisions on the extent of cement replacement by other cementitious materials.
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Lightweight aggregates have been manufactured by sintering fly ash and crushing the product into suitable sizes. These aggregates possess unique characteristics that make them suitable for high strength and high performance concrete.... more
Lightweight aggregates have been manufactured by sintering fly ash and crushing the product into suitable sizes. These aggregates possess unique characteristics that make them suitable for high strength and high performance concrete. Concrete produced using these aggregates is around 22% lighter and at the same time 20% stronger than normal weight aggregate concrete. Drying shrinkage is around 33% less than
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Abstract The influence of an Australian flyash on Cl− and OH− ion concentration of cement mortar pore solutions was investigated by preparing NaCl and CaCl 2-bearing mortars with 30% replacement of cement with flyash, and analyzing the... more
Abstract The influence of an Australian flyash on Cl− and OH− ion concentration of cement mortar pore solutions was investigated by preparing NaCl and CaCl 2-bearing mortars with 30% replacement of cement with flyash, and analyzing the pore solutions extracted from ...
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Abstract 1% of Cℓ− ion by weight of cementitious materials was added as CaCℓ 2 to mortar mixes with and without flyash. Accelerated carbonation was applied on the mortars after short and long fog curing periods. The results showed... more
Abstract 1% of Cℓ− ion by weight of cementitious materials was added as CaCℓ 2 to mortar mixes with and without flyash. Accelerated carbonation was applied on the mortars after short and long fog curing periods. The results showed significant increase of Cℓ− ions in ...
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Two methods were used to determine the 'free'and 'water soluble'chloride ions concentration in four differing strength grade concretes. Each grade of concrete had varying concentration of Cl− admixed as... more
Two methods were used to determine the 'free'and 'water soluble'chloride ions concentration in four differing strength grade concretes. Each grade of concrete had varying concentration of Cl− admixed as NaCl. In all 24 different batches of concretes were made with admixed ...
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... Determination of chloride ion concentration was performed according to ASTM standard methods C 1152 ... via an electrical wire whose end was welded to the rebar before casting. ... the steel depth has exceeded the British Standards... more
... Determination of chloride ion concentration was performed according to ASTM standard methods C 1152 ... via an electrical wire whose end was welded to the rebar before casting. ... the steel depth has exceeded the British Standards threshold value of 0.4% for corrosion initiation. ...
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In this study, the two rapid chloride permeability tests; the AASHTO's rapid chloride permeability test (RCPT) and the University of Cape Town (UCT) chloride conduction test were employed and compared using concrete specimens cast... more
In this study, the two rapid chloride permeability tests; the AASHTO's rapid chloride permeability test (RCPT) and the University of Cape Town (UCT) chloride conduction test were employed and compared using concrete specimens cast with effective w/b ratio of 0.48 and applying ...
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ABSTRACT This paper investigates the flexural properties of self-compacting fibre reinforced cementitious composites that contain high fly ash volume. Seven types of fibres were compared at the same volume fraction and in similar matrices... more
ABSTRACT This paper investigates the flexural properties of self-compacting fibre reinforced cementitious composites that contain high fly ash volume. Seven types of fibres were compared at the same volume fraction and in similar matrices containing high-volume fly ash and having a high compressive strength of around 85 MPa at 28 days. Third-point bending test was conducted on beam specimens to obtain their load-deflection curves, and investigate their fracture behaviour, flexural strength, deflection and toughness. The results showed that using straight steel and micro polyvinyl alcohol fibres produced composites demonstrating stable deflection-hardening with multiple-cracking phenomenon. This behaviour resulted in high flexural strength, along with large maximum deflection and toughness values, which are important for applications in cementitious composites. This study indicates that fibres with both sufficiently high aspect ratio and high tensile strength are necessary for achieving deflection-hardening in self-compacting cementitious composites with high-strength matrices containing high-volume fly ash.