In this work, marl clay was used because these materials have a very important industrial potentiality in several fields, namely ceramics. The objective was manufacturing expanded clay aggregate (ECA), with two main ingredients of marl and pozzolan at different percentages in order to integrate them into the concrete as aggregate. The physicochemical parameters of the mixture marl / Pozzolan was discussed and the results of the analyses, allowed deducing that the sample with 15% pozzolan has the most expansion rate of 16.8%, and its density of 1232 kg/m3 is in accordance with the international standard of expanded aggregates. The density of the concrete decreases with the quantity of ECA added and reaches its minimum with 1671 kg/m3 according to concrete with 50% of the expanded aggregate. The bending tests show the increase of the mechanical strength as a function of the quantities of aggregate added. The results show a very important potential with the addition of clay aggregates, density and water absorption decrease with the increase of the mechanical resistance.
The research aims to study the purification performance of a local and natural material as an input or as a biological filter for treating urban domestic wastewater. For this purpose, pozzolan was used as the biofiltration support that was provided from Beni Saf located in the North-West of Algeria. Tests were carried out with a specially modified pilot unit (TE900) for wastewater treatment over a period of four months. To assess the efficiency of the treatment, two main parameters have been focused on - the height of the sprinkler filter (40 cm and 80 cm) and the flow rate (10, 16, and 25 dm3∙h-1). Physicochemical and bacteriological analyses were carried out on raw wastewater and treated water. The obtained results show that the Beni Saf pozzolan-filled trickling filter eliminates a large fraction of the studied pollutants. The purification yields obtained are fairly encouraging; 98% for turbidity, 88% for suspended solids (SS), 94% for chemical oxygen demand (COD), and 98% for biological oxygen demand (BOD5 ). As for bacterial indicators, the formation of biofilms has significantly reduced bacterial activity with a percentage of over 80%. It can be concluded that the reduction of pollutant parameters clearly indicates the effectiveness of the treatment by this ecological process. Therefore, the use of local and natural materials for wastewater treatment can be a promising alternative based on sustainable environmental technologies and development.
Purpose: In building constructions, due to the decrease of local raw materials and for sustainability purpose, beside the need of light pieces to be used in roofing and false ceiling; an alkali-activated mortar is the new development where pozzolanic material is used instead of cement and activated by an alkaline solution. Therefore, in this research, alkali-activated mortar containing unexpanded clay as a fine aggregate with a dry density of 1652 kg/m3, compressive strength of 3.2 MPa, and thermal conductivity of 0.4 (W/m.K) was produced ,also boards were performed in a dimension of 305×152×12 mm as to use them in false ceiling, and reinforced with 0.25 and 0.5% steel fibre to improve their toughness by 370.8% and 1146.1% compared with reference boards, which made them good choice to used them in roofing and secondary ceiling. Design/methodology/approach: For preparation of alkali-activated mortar, low calcium fly ash (FA) was used as a source binder material. In addition, super-plasticizer and unexpanded clay as a fine aggregate (produce from the crushed artificial aggregate) in the ratio of 1:2.75 fly ash/fine aggregate. The paste was prepared by mixing fly ash with an alkali silicate solution, in a solid-to-liquid ratio of 0.4. Alkali silicate activator was prepared by mixing the NaOH and Na2SiO3 solutions at the mass ratios of 2.5. The concentrations of the NaOH was the same molarity of (14M).To improve the mechanical properties of the reference mortar mixture ,steel fibre with 0.25 and 0.5% content were added to the mix .The specimens were tested for water absorption, dry density, compressive strength, flexural strengths, flexural toughness, and thermal conductivity, in addition to the Scanning Electron Microscope test (SEM) for all mortar mixes. Alkali-activated mortar boards with (305×152×12 mm) were prepared and tested for flexural strength and toughness. Findings: The results indicated that the modulus of rupture for mortar boards reinforced with 0.25 and 0.5% steel fibre exhibits an increase of (3.68-12.10)%. In comparison, the toughness is increased by about 370.8% and 1146.1%, respectively, as compared with the reference mortar (without fibre) which made them resistance to accident, in addition to use them in roofing due to their thermal insulation. Research limitations/implications: Further research is needed to make a similar board using another sustainable material. We can examine the thermal insulation that we can get from these board, especially in the building in Iraq which the weather faces high temperatures. Practical implications: There is a by-product that we could get from the electricity station in Iraq. We must study how we get rid of it. Originality/value: This paper investigate how to produce a new light board using artificial aggregate made from unexpanded clay, which has many benefits in building insulation roofing.
During cement production, a significant amount of CO2 is released into the atmosphere, it is estimated that the production of each ton of clinker free about a ton of second carbon oxide. The use of additions as constituents of cement reduces the amount of clinker, where CO2 emissions are reduced. The combination of two or three additions with Portland cement can develop new types of binders (ternary or quaternary cement) with improved physical and mechanical properties compared to Portland cement alone. The objective of this work involves the study of the effects of the fineness of limestone on the physical and mechanical properties of ternary cements containing pozzolan and limestone with specific area of 3500, 5500 and 11000 cm2/g, respectively. The amount of clinker is fixed at 65% , that of limestone is varied from 10 to 35% by weight of cement, the remain is constituted of pozzolanic addition. The results showed that increasing the surface area of limestone could be with a favorable effect on the physical properties in particular the setting time and the shrinkage; further to good strength, mainly at early ages. The higher dosages of pozzolan reaching 25 % gave better mechanical performances among all other mixtures. It can be concluded that the use of combined mineral additions, limestone and pozzolan could be beneficial to formulate ternary cements with improved physical and mechanical properties for mortars based on such binders.
The use of cement resistance to sulphate in aggressive environments showed a lot of benefits such us good mechanical development and therefore better durability; however, the consumption for great amount of clinker lead to random hazardous deposits, shortage of natural resources, gas and dust emissions mainly (CO2) causing negative impact on the environment. Recently, technical, economic and environmental benefits by the use of blended cements have been reported and being considered as a research area of great interest in cement production industry. The present research aim is to evaluate the effect of partial replacements of cement resistant to sulfate (CRS) by a pozzolanic addition, on the physical-chemical properties, as an alternative novel composition binder. Furthermore, the behaviour of the mortars based on this new combined blends was investigated in the study program, including chemical composition, density and fineness, consistency, setting time, swelling, shrinkage, absorption and mechanical behaviour. The results obtained showed that the substitution of pozzolan at the optimal ratio of 5% had a positive effect on the resulting cement properties, namely: greater specific surface area, reduced water demand, accelerated process of hydration, better mechanical behaviour and decreased water absorption. Therefore, economic and ecological cement based on mineral addition like pozzolan could be possible as well as advantageous to the formulation of environmental performance mortars.
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