ECTechnology Vancouver via EcoSmart provided ICON CANMET with a new superplasticizer produced by Rhein Chemotechnik GmbH Breitscheid Germany the ALPHALITH FT30LV which meets the European standards and certifications for analyzing and testing of its suitability for the Canadian market. The superplasticizer belongs to the family of naphthalene formaldehyde condensates-based superplasticizers. A commercially available Canadian superplasticizer from this family which is commonly used and known to be very efficient in the improvement of cement pastes flow was used in this study for comparison.
Tests -the Marsh cone test and the mini-slump test- were done on grout to determine the efficiency of both superplasticizers as dispersing admixtures of cement pastes. Tests on concrete were performed to ensure that this admixture does not induce bad side effects such as segregation increasing of air content of the concrete setting retardation etc.
The FT30LV is compatible with the Canadian cement used but the dosage to obtain a good fluidity of the cement pastes is higher than that of the Canadian superplasticizer. No retardation of the setting is observed even if the dosage of the superplasticizer is fairly high. The one-day compressive strength of the concrete made with the FT30LV superplasticizer was similar to that obtained with the reference superplasticizer which is an indication that this admixture has not negatively affected the hardening of the concrete.
Technical Report Author: Benoit Fournier, Pierre-Claver Nkinamubanzi, CANMET Energy Technology Centre, Natural Resources Canada,
This paper presents results on the compressive strength of mortars in which 10 and 20% of ASTM Type I cement has been replaced by ground fly ash from two different sources. The results are compared with those of the mortars made with ASTM Type I cement and with the mortar in which 10% of portland cement has been replaced by silica fume. The results show that the mortars made with 20% replacement of cement by the fine Sundance fly ash that had been ground for 2 hours achieved a 28-day compressive strength that was 90 to 93% of the strength of the mortars incorporating 10% silica fume as cement replacement. However for the coarse fly ash the results were not encouraging: even increasing the grinding times of the fly ash up to 10 hours did not yield the compressive strengths approaching that of the silica fume mortars. The report includes tables and figures that detail the results of the study.
Technical Report Author: Nabil Bouzoubaa, V.M. Malhotra, CANMET Energy Technology Centre, Natural Resources Canada,
Since their introduction in the early 60â€™s superplasticizers have become an essential component of concrete. By reducing the amount of water in concrete superplasticizers have contributed to a significant reduction in its porosity and to a concomitant increase in its compressive strength and durability. These chemical admixtures have also been at the forefront of the use of mineral admixtures such as silica fume fly ash and blast-furnace slags in high performance concrete. By making possible the use of these industrial by-products as a partial replacement of cement superplasticizers are also helping to reduce the emission of CO2 in the atmosphere a key issue in several industrialized countries.
This paper reviews some important aspects related to the use of superplasticizers in concrete. More precisely it concentrates on how these polymers contribute to sustainable development by favoring the use of mineral admixtures in concrete and by increasing the durability of concrete structures.
Technical Report Author: Monique Page, Nelu Spiratos
This paper reports on CANMET s development of high volume fly ash -HVFA- blended cements and their performance in concrete. The blended cements are made by intergrinding approximately 55% of fly ash and 45% of ASTM Type I or Type III cement clinker together with small amounts of gypsum and a dry superplasticizer. The concrete made with the HVFA blended cements has adequate early-age and excellent later-age mechanical properties and demonstrates satisfactory performance in durability aspects such as resistance to freezing and thawing cycling and chloride ion penetration.
Technical Report Author: Nabil Bouzoubaa, M.H. Zhang, V.M. Malhotra, CANMET Energy Technology Centre, Natural Resources Canada,
This report outlines the preliminary results of a research project aimed at optimizing the fly ash content in concrete. Such fly ash concrete would develop an adequate 1-day compressive strength and would be less expensive than the normal Portland cement concrete with similar 28-day compressive strength.
The results show that in a normal portland-cement concrete having a 28-day compressive strength of 40 MPa. it is possible to replace 50% of cement by a fine fly ash -~3000 cm2/g- with a CaO content of ~ 13% yielding a concrete of similar 28-day compressive strength. This concrete air-entrained or not can be designed to yield an early-age strength of 10 MPa. and results in a cost reduction of about 20% in comparison to the control concrete. In a case of a coarser fly ash -~2000 cm2/g- with a CaO content of ~ 4% substitution levels of cement by this ash could be from 30 to 40%. This concrete yields a 1- day compressive strength of 10 MPa. and 28-day compressive strength similar to that of the control concrete. The total cost of this concrete is about 10% lower than that of the control concrete. The above fly ash concrete are made without the use of a superplasticizer and are found to have higher resistance to chloride-ion penetration than the control concrete.
Technical Report Author: Nabil Bouzoubaa, Benoit Fournier, CANMET Energy Technology Centre, Natural Resources Canada,