A Review on Mechanical Properties of Sustainable Concrete by using Rise husk ash and hydrated lime

Concrete is a commonly used construction material all over the globe. Environmentally conscious construction is essential in today’s society. By using the proper materials, we may achieve long-term construction. RHA is often used as a cementitious product replacement, and in such cases, we may mix RHA with hydrated lime. Many research has been conducted on RHA, and they all indicate that it outperforms other kinds of concrete. The importance of rice husk ash in construction and its applications are the subject of this essay. Many studies have been undertaken to identify appropriate replacements for cement in concrete mixes to reduce our over-reliance on cement as a component in concrete production owing to its contribution to CO2 emissions. This article examined the research on the usage of fly ash and rice husk ash as partial concrete replacements and the chemical composition of these materials, and their impact on concrete compressive strength. The mix was created using a logical approach in which solid components were set, and water and superplasticizer content were modified to get the best viscosity and flowability. Rice husk ash (RHA) is a rice milling byproduct. Its usage as a soil stabilizer provides an environmentally friendly alternative to ultimate disposal. Because RHA is not self-cementitious, a hydraulic binder, such as lime, must be added to create cement types to strengthen the soil. In sandy soils, studies on stabilization using RHA and lime mixtures were carried out. RHA of rice husk incineration in ordinary ovens with no temperature control and laboratory burning at regulated temperatures were utilized. In soil mixes with varying RHA and lime concentrations, cementitious compounds were found to develop. Soils treated with RHA and lime underwent unconfined compression strength testing. All RHA and lime concentrations and periods tested showed strength gains, and all materials created were changed rather than stabilized. The use of RHA to improve sandy soils offers environmental, social, and economic advantages as an alternative to ultimate disposal.

A Review on Mechanical Properties of Sustainable Concrete by using Rise husk ash and hydrated lime

Concrete is a commonly used construction material all over the globe. Environmentally conscious construction is essential in today's society. By using the proper materials, we may achieve long-term construction. RHA is often used as a cementitious product replacement, and in such cases, we may mix RHA with hydrated lime. Many research has been conducted on RHA, and they all indicate that it outperforms other kinds of concrete. The importance of rice husk ash in construction and its applications are the subject of this essay. Many studies have been undertaken to identify appropriate replacements for cement in concrete mixes to reduce our over-reliance on cement as a component in concrete production owing to its contribution to CO2 emissions. This article examined the research on the usage of fly ash and rice husk ash as partial concrete replacements and the chemical composition of these materials, and their impact on concrete compressive strength. The mix was created using a logical approach in which solid components were set, and water and superplasticizer content were modified to get the best viscosity and flowability. Rice husk ash (RHA) is a rice milling byproduct. Its usage as a soil stabilizer provides an environmentally friendly alternative to ultimate disposal. Because RHA is not self-cementitious, a hydraulic binder, such as lime, must be added to create cement types to strengthen the soil. In sandy soils, studies on stabilization using RHA and lime mixtures were carried out. RHA of rice husk incineration in ordinary ovens with no temperature control and laboratory burning at regulated temperatures were utilized. In soil mixes with varying RHA and lime concentrations, cementitious compounds were found to develop. Soils treated with RHA and lime underwent unconfined compression strength testing. All RHA and lime concentrations and periods tested showed strength gains, and all materials created were changed rather than stabilized. The use of RHA to improve sandy soils offers environmental, social, and economic advantages as an alternative to ultimate disposal

Evaluation of a Marine Dredged Sediment as Raw Material Compared to Volcanic Scoria for the Development of Lime-Pozzolan Eco-Binders

In the context of global warming, the built environment offers relevant opportunities to reduce GHG emissions that underlie climate change. In particular, this can be achieved with the development of low-embodied energy building materials such as bio-based concretes. Hemp concrete has been the subject of many investigations in the field of non-load bearing infill walls in France since the early 1990s. In addition to hygrothermal performances, the use of crop by-products definitely helps to limit the carbon footprint. Hemp concretes are often produced by mixing the plant aggregates with lime-based binders. The latter have many benefits among which the water vapor permeability. However, CO2 emissions due to the decarbonation of limestone for the production of lime largely contribute to the overall environmental balance of these materials. The use of natural pozzolans (volcanic scoria) combined with hydrated lime goes back to the Greco-Roman period and reduces carbon emissions. Nonetheless, it does not necessarily meet the issue related to the depletion of granular natural resources. Hence, this study deals with the design of a new low-carbon binder based on marine dredged sediment seen as an alternative strategic granular resource that can be considered renewable. The sediment comes from the Port of Dunkirk in the North of France and is mainly composed of silt and quartz sand. It was finely ground and compared to a lowly reactive basaltic pozzolan. Lime-pozzolan pastes were prepared and stored in a moist environment under room (20°C) and high temperature (50°C). The hardening kinetics of pastes was followed through mineralogical studies (TGA, XRD) and compressive strength development. The results showed that the hardening of pastes including the marine sediment was suitable in the case of samples stored at 50°C and make it possible to use such a binder for precast bio-based concretes.

Evaluation of Bio-Based Earth Engineered Mortars for Low Energy and Carbon Buildings in Tropical and Subtropical Climates

Improving the thermal performance of low-income housing in developing countries, located in tropical and subtropical regions, is one of the main challenges of the building sector. The use of mortars as building cladding is a current practice in many developing countries. Bio-based (such as bamboo particles) and earth materials have shown interesting potential for improving some thermal properties of covering mortars. In addition, bio-based earth mortars can have a lower carbon footprint than conventional mortars (typically made of cement or cement with lime) used in the building sector. The aim of this study is the evaluation of the life cycle GHG emissions of different mixtures of an engineered bio-based earth mortar mixed with bamboo particles, earth, and different cementitious materials (Portland cement, hydrated lime, metakaolin, and fly ash) and water. Four mixtures are evaluated: without bamboo particles, with 3%, 6%, and 9% of bamboo particles in volume. The thermal energy performance and carbon footprint of these mortars are evaluated. From physical tests carried out in the laboratory, thermal energy simulations are carried out in DesignBuilder software considering a case study of a social housing project in Brazil, evaluating tropical and subtropical climates. Finally, the carbon footprint was performed, using the Life Cycle Assessment (LCA) methodology considering a cradle-to-gate scope. When compared with two conventional mortars (made of cement and hydrated lime), the bio-based earth mortar presents better thermal energy performance and a lower carbon footprint. We can conclude that there is a potential to improve the thermal energy performance in low-income housing and, at the same time, to reduce the mortar carbon footprint. This mortar can be produced where bamboo and cementitious materials are available, which is the case in several developing countries that are expected to have a substantial housing demand for new buildings in the coming years.

Physical, Thermal and Microstructural Characterization of Earth Mortars Stabilized with Incorporating Air Additive

In recent years, the search for non-conventional materials has intensified, aiming to reduce environmental impacts in the civil construction sector as a strategy for more sustainable development. Among these materials, earth mortars are a promising option, as they have technological, economic, and environmental advantages. Due to the absence of literary data on the use of air-incorporating additives (AEA) in earth mortars, the objective of this article is to verify the influence of the incorporation of AEA (0,10, 20, and 40% of the total volume of the mixture) in the mechanical properties (compression strength at 28 days), physical (total water absorption by immersion), thermal, and microstructural (scanning electron microscopy) of the referred mortars. The study was carried out in a stabilized earth mortar, with a 1:3 mass mix proportion (binder: aggregate). The raw materials used were constituted by binders (cement, hydrated lime, fly ash, metakaolinite), aggregates (sand, a coarse fraction of the soil), additives (AEA, calcium chloride, superplasticizer), and water. The water-binder material ratio (a / bm) was fixed at 0.65, and the consumption of binder and aggregate was 461.71 and 1385.12 kg, respectively, per m3 of the mixture. The tests demonstrated that the incorporation of the additive influenced the behavior under compression (strength and stiffness reduction), thermal performance (conductivity reduction), and physical behavior (absorption and voids index´s increases) compared to the mixture without AEA. From the analysis of the results, it was found that the incorporation of air in the mortars led to an increase in porosity, directly influencing the thermal insulation capacity, measured by thermal conductivity. Microstructure changes were observed through SEM images, corroborating the influence of the AEA. Under compression loads, the stiffness reduction decreases the risk of eventual cracking, however, the reduction in strength should be controlled to meet normative limits.