This paper studies the use of cockle shell as supplementary cementitious materials SCMs as substitute for cement. The cockle shells generally have a high CaO content which can alter the behavior and the properties of mortars and concrete. Cockle shell is used with weight ratios of 5, 10, 15 and 20% to formulate a mortar with cockle shell and a control mortar CM with 0% of cockle shell. The properties in the fresh state, the mechanical strength and the weight loss test as well as the depth of penetration of each mixture were carried out through the conducted experiments. Consistency and density of fresh mortars were determined, the results obtained showed that cockle shell have a significant influence on the properties of mortars in the fresh state.
The different results of hardened mortars show that the introduction of cockle shell tends to accelerate the development kinetics of strength at the young age but its ratio cannot be above of 5%. Mortar with 10% presented the lower depth penetration, the loss weight increased proportionally with the increasing of cockle shell amount.
The introduction of treated plant fibres into sand concretes leads to a reduction in density, improved ductility and thermal conductivity, and makes sand concrete an environmentally friendly and ecological material. The recovery of waste in this type of material allows the production of new ecological and sustainable materials used either in the new construction or in the rehabilitation of old buildings. In this context, a comparative study was based on the valorisation of marble and ceramic waste as sand in sand concrete made from straw fibres. To carry out this study, we introduced these wastes at substitution rates of 10% and 20%, separated and mixed, and studied the development of the properties of these concretes (density, workability, air content, compressive strength and bending tensile strength) and their behaviour with respect to durability (capillary and immersion absorption and chloride penetration). The study shows that the recovery of this waste as sand in sand concrete based on straw fibres gives satisfactory results. The chemical resistance, thermal conductivity and microstructure are under study, the results of which will be the subject of another publication.
The present study aims to valorize the waste and in particular the waste from the Fil-fila quarry. The main reason for choosing the waste from this quarry was the need to reduce the impact on the environment (by reducing stockpiling) and the raw material cost (economic reason). This study therefore consists in recovering this type of waste (discarded powder subject to weather changes) as sand in partial replacement of dune sand in the formulation of sand concrete with percentages of 5, 10, 15 and 20 %, by studying the behavior of these concretes in the fresh state (workability, density and occluded air) and the properties in the hardened state (compressive and tensile strength by bending, absorption by immersion, shrinkage and weight loss, chemical effect of HCl and H2SO4 solutions), and subsequently comparing the results obtained with reference samples (0%) based on ordinary sand. Based on the obtained results, it can be concluded that the substitution of ordinary (dune) sand with marble waste sand provides acceptable results from the point of view of workability, strength and durability.These observations are likely to widen the field of applications of these sand concretes based on marble waste.
The aim of this research is to assess the mechanical performance of self-compacting concrete containing different percentages of fine aggregates, produced from the wastes generated by the cement plant industry and construction sites. Eight mixes, incorporating cement kiln dust (CKD) and hardened cement waste with partial fine aggregate replacement of 5%, 10%, 15%, and 20%, were produced and compared with a control mix made with 100% of crushed sand. The workability properties (e.g., flowability, passing ability, and resistance to segregation) and mechanical properties (e.g., compressive, flexural, and splitting tensile strengths) of all mixes were evaluated. The results showed that concretes containing recycled fine aggregates proved to have the best mechanical properties, compared to one made with crushed calcareous sand. However, self-compacting concrete with high mechanical strength could be produced with up to 15% wt. CKD replacement and with 10% wt. hardened cement waste replacement.
The aim of this research is to study the possibility of the valorization of sand marble waste in mortars as substitute in sand. To achieve this study, sand marble waste is used with weight ratios of 5, 10, 15 and 20% to formulate a mortar with sand marble waste and a control mortar with 0% of sand marble waste. The properties in the fresh state, the mechanical strength, absorption by immersion, and the weight loss as well as the shrinkage and acid attack of each mixture were carried out through the conducted experiments. The different results show that the introduction of recycled sand in the mortars gives good results and it can be used as aggregates.
This work revolves around the study of the partial substitution of cement by biomass ash (residue generated during incineration of wood waste) in mortar. The introduction of wood ash in the cement formulation allows solving some problems related to the lack of construction materials and protecting the environment. To carry out this work we have introduced wood ash as an addition which partially substitutes cement at three different replacement percentages (5%, 10% and 15%). We carried out tests on mortar in the fresh state (consistency, density and occluded air); evaluated its performance in the hardened state (compressive and flexural tensile strength), dimensional stability and its durability (water absorption by immersion and by capillarity as well as resistance to chlorides and acidic environments followed by XRD). Results obtained will be compared with the results of control samples with 0% substitution rate.
The results of this valorisation show that the incorporation of 5% of ash fillers in the cement improves mechanical resistance as well as certain durability parameters.
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