Thermal and mechanical behavior of composite mortars containing natural sorptive clays and fly ash

Abstract

Mineral additives are extensively applied as cement replacement materials in both construction concrete and mortar. Fly ash is one of the most commonly utilized additives which improve rheological properties, as well as thermal and mechanical behavior of mortar, and as such it has been widely investigated. This industrial byproduct comprises heavy metals in its composition; therefore further research is needed to optimize its effective dosage. Moreover, certain sorptive clays, such as natural zeolite and bentonite, can prevent migration of toxic elements from fly ash by immobilizing them in their structure. Ten experimental mortars are prepared with Portland cement, river sand and addition of fly ash, zeolite and/or bentonite in accordance with chemometric experimental design rules. The aim of the study was to investigate the effect of mineral additives on thermal and mechanical performances of mortar. Thermal characteristics were monitored via dilatometric analysis and DTA method. Principal component analysis was used on the results of physico-mechanical testing (workability, bulk density, water absorption, shrinkage, compressive and flexural strength) to enable the divisions of the observed samples into groups in the factor space. The performance of Artificial Neural Network was compared with the experimental data in order to develop rapid and accurate method for prediction of mechanical parameters of mortar. The ANN model showed high overall prediction accuracy (r 2 = 0.989, during training cycle). The test results indicate that incorporation of the mineral additives gave cost effective mortars with sufficiently good properties. However, tools of analytical modeling highlighted mortar with zeolite and fly ash as the optimal composition regarding its mechanical performance.

Study of nanosized hydroxyapatite material annealing at different retention times

“…The similar grain growth and morphologies of hydroxyapatite grains are achieved by using other methods: changing pH during synthesis, using some additives as polyethylene glycol as template to obtain lamellar and rod shaped hydroxyapatite materials [37,38]. Due to energy savings and environmental protection low energy annealing method has been more used lately [39,40]. Artificial hydroxyapatite material to be used as an implant for example bone implant has to have a hollow and reticulate structure and yet the powder needs to remain nanocrystalline and monophase which we achieved just using prolonged retention time on low temperature treatment.…”

Effect of sintering temperature and calcium amount on compressive strength of brushite-metakaolin polymer materials

“…[2] Therefore, the replacement of conventional cement, plastics, and many mineral-based products would have a positive impact effect reducing CO 2 emissions from cement clinkers, limiting toxic metal contamination of freshwater resources resulting from mining operations, and reducing the over-use of common organic plastics. [3] This motivated many researchers to identify materials that to sustainable development, such as promoting recycling and managing solid waste or the reuse of abandoned raw materials [4][5][6][7][8].…”

Durability properties of ladle slag geopolymer mortar based on fly ash

“…Instead, most of them are recognized as a secondary raw material [6]. The use of waste material in the production of new composite materials is a common practice which is in accordance with the environmental requirements [7]. So far, many performances of geopolymer mortar have been examined…”