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

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.

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
M. A. Othuman Mydin

Splitting tensile strength of concrete is normally low compared to compressive and flexural strength. Tensile force was used in the design of structural foamed mortar and to evaluate the shear resistance provided by concrete. This research focuses on the splitting tensile strength of foamed mortar incorporated with 7 different types of fibres used such as wood ash, pulverized fuel ash, silica fume, palm oil fuel ash, polypropylene fibre, coconut fibre and steel fibre. The findings show that the amount of fibres influences the enhancement level of the tensile strength. A high percentage of fibre can create a strong bonding between the particles of the foamed mortar, thus it is able to absorb energy to resist crack formation.


2011 ◽  
Vol 2 (1) ◽  
pp. 7-11
Author(s):  
Gingos G.S. ◽  
Mohamed Sutan N.

Partial replacement of cement by mineral admixtures or pozzolans can possibly improve the durability of mortar which directly related to its water absorption. Pulverized Fuel Ash (PFA) is one of the pozzolans that is locally available. Laboratory studies have been conducted on mortar mixes of 0.3w/c, 0.4w/c and 0.5w/c ratios with 10%, 20% and 30% PFA replacements. Mortar cubes were tested to determine their water absorption rates and compressive strengths as they mature. Amount of PFA replacements in the mortar has significant effects on the strength development and water absorption rate of the mortar. Results shows that 20% PFA mortars of 0.5w/c ratio is the best mix to reduced rate of water absorption and achieved higher compressive strength.


1985 ◽  
Vol 65 ◽  
Author(s):  
Magne Maage

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.


1986 ◽  
Vol 86 ◽  
Author(s):  
C. S. Poon ◽  
R. Perry

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.


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