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Showing 1-5 of 60 Abstracts search results

Document: 

SP178-30

Date: 

June 1, 1998

Author(s):

W.S. Langley and G. H. Leaman

Publication:

Symposium Papers

Volume:

178

Abstract:

Concrete containing fly ash has been used in many parts of the world for several decades. Various standards and codes have generally limited the use of ASTM Class F fly ash from 20 to 25 percent. Laboratory studies and field demonstration projects sponsored by CANMET during the last 12 years have shown that concrete containing 55 to 60 percent fly ash has excellent structural and durability characteristics when proportioned with superplasticizers and at low water to cementing materials ratios. This paper presents some results of research performed under contract to CANMET and some of the practical uses for which the high-volume fly ash concrete system has been utilized in Eastern Canada. The applications discussed include structural concrete, relatively massive machinery foundations, a roller compacted dam, environmental applications such as impermeable shotcrete covers and encapsulation/solidification, and design of mine backfills. The high-volume fly ash system has proven to be an economical construction material which can be mixed, placed and consolidated with conventional concrete construction equipment. Some unique properties such as very low heat generation, low cost, and the possibility to use large quantities of fly ash will expand the future use of the high volume fly ash system.

DOI:

10.14359/5998


Document: 

SP178-51

Date: 

June 1, 1998

Author(s):

J. Pera, E. Bonnin and M. Chabannet

Publication:

Symposium Papers

Volume:

178

Abstract:

Metakaolin-blended cements were used to stabilize two kinds of wastes: municipal incinerator fly ash and latex waste coming from the carpet industry. The physical and chemical properties of wastes were investigated and mortars containing these wastes were cast. A blended cement containing 20 % metakaolin was utilized to immobilize the incinerator fly ash which was introduced as a sand substitute in mortars. Leaching tests and microstructural investigations were carried out as well as mechanical tests. The results obtained show that metakaolin plays a beneficial effect in the stabilization of chlorides contained in such fly ash. Cements containing from 10 to 30 % metakaolin were used to cast mortars, in which latex was introduced as a sand substitute. Metakaolin reacted with the calcite contained in the latex and the C3A of portland cement to form carboaluminate. Leaching tests showed a good immobilization of this waste.

DOI:

10.14359/6019


Document: 

SP178-02

Date: 

June 1, 1998

Author(s):

K.E. Hassan and J.G. Cabrera

Publication:

Symposium Papers

Volume:

178

Abstract:

Waste materials may be upgraded to specification standards and occasionally to premium materials for use in the preparation of composites or for use in their own. The treatment for upgrading is a matter of cost and of the potential environmental problems that the treatment can create. The investigation presented in this paper shows an example of the improvements of fly ash properties achieved by a simple physical process, that is, air cyclone separation. This process gives a very line ash with adequate pozzolanic activity and is suitable for producing high performance concrete with excellent durability particularly when exposed to aggressive environments. The paper presents data on the properties of the fine fly ash including lime reactivity, composition, size distribution and shape. The investigation was carried out using two fly ashes obtained by the process of air separation using a prototype small air cyclone separator and an air mini-splitter. The properties of these ashes were compared to the properties of the original raw ash and with the properties of a fly ash processed industrially by the conventional mechanical separation process, which produces a fly ash conforming to the appropriate British specifications for use in the production of structural concrete. In this test programme, high performance concrete made with 0.3 fly ash and 0.7 ordinary Portland cement (by weight) as binder was assessed by measuring strength, porosity, and permeability. These properties were used to evaluate the performance of concrete and potential long term durability.

DOI:

10.14359/5970


Document: 

SP178-55

Date: 

June 1, 1998

Author(s):

D.D. Higgins, J.M. Kinuthia and S. Wild

Publication:

Symposium Papers

Volume:

178

Abstract:

Soil stabilisation with cement or lime, is a well established technique for use in highway or foundation construction. Extensive laboratory investigations and a full-scale trial have been carried out to evaluate the performance of ground granulated blastfurnace slag (ggbs) in combination with lime, for stabilising soils. This paper reports the results of laboratory tests for strength and swelling, and also describes the full-scale trial. The applicability of lime / ggbs combinations has been demonstrated. In addition laboratory tests have shown a previously undemonstrated advantage where the incorporation of ggbs combats the deleterious swelling which can occur when sulphate-containing soils are stabilised with cement or lime.

DOI:

10.14359/6023


Document: 

SP178-16

Date: 

June 1, 1998

Author(s):

J. G. Agron

Publication:

Symposium Papers

Volume:

178

Abstract:

Coincident with the investigation of the utilization of Mount Pinatubo ejecta on the production of paving blocks for sidewalks, parking areas and other footpaths, a study on the durability of the blocks was also undertaken. Blocks with a plan area of 1OOmm x 200mm and a thickness of 85mm were prepared with three mixture proportions. The mixture proportions were prepared to represent three strength levels. Specimens from each mixture were subjected to both natural and accelerated weathering conditions. The compressive strength in accordance with ASTM C 936 and the abrasion resistance in accordance with ASTM C 779 were determined for various ages. The test results as shown in this paper for the durability parameters selected, show favorable long term properties of the paving blocks.

DOI:

10.14359/5984


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