Carbonation in Concrete Made of Blended Cements

1985 ◽  
Vol 65 ◽  
Author(s):  
Magne Maage
Keyword(s):  
Natural Environment ◽  
Ordinary Portland Cement ◽  
Cement Clinker ◽  
Exposure Condition ◽  
Curing Time ◽  
Blended Cements ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Pulverized Fuel Ash ◽  
Different Climates

ABSTRACTConcrete with different strengths was produced using four types of cements, one ordinary Portland cement (OPC) and three blended cements with 10% pulverized fuel ash (pfa), 25% pfa, and 15% slag respectively. The pfa was added to the cement clinker during the end of the grinding process. The the slag was preground. Carbonation was tested using the phenolphtalein method. The concretes were exposed to four different climates: (1) 50% RH, 20 C and normal CO2 content (0.03%) of air; (2) 50% RH, 20 C and 0.1% CO2; (3) outside in the natural environment unsheltered from rain; (4) outside in the natural environment sheltered from rain. Curing time before exposure was varied. The preliminary results showed that concrete with blended cements carbonated somewhat faster than concrete with OPC. The influence of curing time before exposure and exposure condition was found to be evident but independent of the blend.

Studies of Zinc, Cadmium and Mercury Stabilization in OPC/PFA Mixtures

1986 ◽  
Vol 86 ◽  
Author(s):  
C. S. Poon ◽  
R. Perry
Keyword(s):  
Heavy Metal ◽  
Ordinary Portland Cement ◽  
Industrial Wastes ◽  
Leaching Test ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Zinc Cadmium ◽  
Pulverized Fuel Ash ◽  
Physical And Chemical ◽  
Heavy Metal Waste

ABSTRACTThe utilization of pulverized fuel ash (PFA) (fly ash) for the stabilization of heavy metal waste is described. Solutions of the group IIB elements (zinc, cadmium and mercury) are used as model materials because of their significance as industrial wastes. The study included aqueous chemistry determinations, a leaching test, the use of SEM to examine microstructure, and compressive strength measurements. The use of PFA in a cementitious matrix lowers the alkalinity of the overall system and thus improves the immobilization of the amphoteric metal such as zinc. The interaction between mercuric solution and PFA plays an important role in improving the retention of the blended system for mercury. SEM results show that the microstructure of the ordinary Portland cement (OPC)/PFA blended system is significantly modified by the incorporation of the waste material. The advantages of using the blended system over a pure OPC system are described in physical and chemical terms.

Factors affecting the frost susceptibility characteristics of pulverized fuel ash

1970 ◽  
Vol 7 (1) ◽  
pp. 69-78 ◽  
Author(s):  
H. B. Sutherland ◽  
P. N. Gaskin
Keyword(s):  
Tensile Strength ◽  
Ordinary Portland Cement ◽  
Hydrated Lime ◽  
Frost Heave ◽  
Relative Importance ◽  
Laboratory Studies ◽  
Factors Affecting ◽  
Fuel Ash ◽  
Pulverized Fuel ◽  
Pulverized Fuel Ash

The results of laboratory studies of the frost susceptibility characteristics of pulverized fuel ash are presented. Four different ashes were investigated, in their plain state, and also after stabilization with ordinary Portland cement and calcitic hydrated lime. Measurements were made of frost heave, permeability, compressive and tensile strength, and heaving pressure. Frost heave was shown to decrease as the strength increased and as the permeability decreased. Values of strength and permeability were found at which the frost heave was reduced to an acceptable value, and the relative importance of strength and permeability in reducing frost heave is discussed. The heaving pressures mobilized are compared with the corresponding compressive and tensile strengths of the ashes.

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