74 research outputs found
Cement equivalence factor evaluations for fluid catalytic cracking catalyst residue
Fluid catalytic cracking catalyst residue (FC3R) is a waste material that can be used as a Portland cement replacement in pastes, mortars, and concrete. The flow table results show that FC3R is a water demanding addition; nevertheless, this effect can be compensated with the use of superplasticizers. The pozzolanic
activity of FC3R was studied observing the mechanical strength evolution with time. Pastes and mortars with FC3R incorporated show higher mechanical strengths than control specimens, indicating the pozzolanic activity of the waste. Cement equivalence factor (k-factor) evaluations were carried out. The k-factor
values for the FC3R pastes and mortars were always greater than one, indicating that in order to maintain the same compressive mechanical strength of the control specimen it is sufficient to replace cement with a smaller amount of catalyst residue, due to the high pozzolanic activity of FC3R. There is a strong agreement
between the k-factor values obtained in pastes and mortars.This work was supported by Ministerio de Ciencia y Tecnologia, Spain (Project MAT 2001-2694).Paya Bernabeu, JJ.; MonzĂł Balbuena, JM.; Borrachero Rosado, MV.; Velazquez Rodriguez, S. (2013). Cement equivalence factor evaluations for fluid catalytic cracking catalyst residue. Cement and Concrete Composites. 39:12-17. https://doi.org/10.1016/j.cemconcomp.2013.03.011S12173
Study of hygral behavior of non-asbestos fiber cement made by similar hatschek process
Preclinical Strategies to Identify Off-Target Toxicity of High-Affinity TCRs
Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease
Costs and Effects of Abdominal versus Laparoscopic Hysterectomy: Systematic Review of Controlled Trials
Objective: Comparative evaluation of costs and effects of laparoscopic hysterectomy (LH) and abdominal hysterectomy (AH). Data sources: Controlled trials from Cochrane Central register of controlled trials, Medline, Embase and prospective trial registers. Selection of studies: Twelve (randomized) controlled studies including the search terms costs, laparoscopy, laparotomy and hysterectomy were identified. Methods: The type of cost analysis, perspective of cost analyses and separate cost components were assessed. The direct and indirect costs were extracted from the original studies. For the cost estimation, hospital stay and procedure costs were selected as most important cost drivers. As main outcome the major complication rate was taken. Findings: Analysis was performed on 2226 patients, of which 1013 (45.5%) in the LH group and 1213 (54.5%) in the AH group. Five studies scored >= 10 points (out of 19) for methodological quality. The reported total direct costs in the LH group (60,114). The reported total indirect costs of the LH group (3,139). The estimated mean major complication rate in the LH group (14.3%) was lower than in the AH group (15.9%). The estimated total costs in the LH group were 3,312 in the AH group. The incremental costs for reducing one patient with major complication(s) in the LH group compared to the AH group was $35,750. Conclusions: The shorter hospital stay in the LH group compensates for the increased procedure costs, with less morbidity. LH points in the direction of cost effectiveness, however further research is warranted with a broader costs perspective including long term effects as societal benefit, quality of life and survival
Durability of Mortar Incorporating Ferronickel Slag Aggregate and Supplementary Cementitious Materials Subjected to Wet–Dry Cycles
This paper presents the strength and durability of cement mortars using 0–100% ferronickel slag (FNS) as replacement of natural sand and 30% fly ash or ground granulated blast furnace slag (GGBFS) as cement replacement. The maximum mortar compressive strength was achieved with 50% sand replacement by FNS. Durability was evaluated by the changes in compressive strength and mass of mortar specimens after 28 cycles of alternate wetting at 23 °C and drying at 110 °C. Strength loss increased by the increase of FNS content with marginal increases in the mass loss. Though a maximum strength loss of up to 26% was observed, the values were only 3–9% for 25–100% FNS contents in the mixtures containing 30% fly ash. The XRD data showed that the pozzolanic reaction of fly ash helped to reduce the strength loss caused by wet–dry cycles. Overall, the volume of permeable voids (VPV) and performance in wet–dry cycles for 50% FNS and 30% fly ash were better than those for 100% OPC and natural sand
Effect of the heat curing on strength development of self-compacting mortars containing calcined silt of dams and Ground Brick Waste
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