New pozzanic industrial wastes for eco-efficient concrete

Concrete is one of the most widely used construction materials in the world. However, the production of Portland cement as the essential constituent of concrete requires a considerable energy level and also releases a significant amount of chemical carbon dioxide emissions and other greenhouse gases (GHGs) into the atmosphere. Thus, seeking an eco-efficient and sustainable concrete may be one of the main roles that construction industry should play in sustainable construction. To make the concrete more eco-efficient, different life cycle phases of concrete products should be considered, such as extraction of raw material, production of constituents, production of concrete, transportation, erection, maintenance, deconstruction or demolition and recycling. Since binder production represents the major part of the environmental impacts , investigations on partial binder replacement by pozzolanic additions or use of environmental friendly binders lead to an eco-efficient concrete. The present study, as the preliminary results of a PhD research project, is an attempt to evaluate the pozzolanic reactivity of some industrial wastes, namely ceramic waste and slate powder, as well as the possibility of using such materials as partial replacement for Portland Cement. Results indicate that a high-strength eco-efficient concrete can be produced using slate powder or ceramic waste with metakaolin as Portland Cement replacement

Tyre rubber wastes based concrete: a review

The volume of tyre rubber wastes is increasing at a fast rate. An estimated 1000 million tyres reach the end of their useful lives every year and 5000 millions more are expected to be discarded in a regular basis by the year 2030. Up to now a small part is recycled and millions of tyres are just stockpiled, landfilled or buried. This paper reviews research published on the performance of concrete containing tyre rubber wastes. It discusses the effect of waste treatments, the size of waste particles and the waste replacement volume on the fresh and hardened properties of concrete

Eco-efficient concrete using industrial wastes: a review

Concrete is one of the most widely used construction materials in the world. However, the production of Portland cement as the essential constituent of concrete requires a considerable energy level and also releases a significant amount of chemical carbon dioxide emissions and other greenhouse gases (GHGs) into the atmosphere. Global demand will increase almost 200 % by 2050 from 2010 levels. Thus, seeking an eco-efficient and sustainable concrete may be one of the main roles that construction industry should play in sustainable construction. To make the concrete more eco-efficient, different life cycle phases of concrete products can be brought to bear such as extraction of raw material, production of constituents, production of concrete, transportation, erection, maintenance, demolition and recycling. Portland cement can be partially replaced by cementitious and pozzolanic materials especially those of industry by-products such as fly ash, GGBS, silica fume, ceramic waste powder and metamorphic rock dust form stone cutting industry. The aggregates are also conserved by replacing them with recycled or waste materials among which recycled concrete, ceramic waste, postconsumer glass, and recycled tires are the most used. This paper summarizes current knowledge about eco-efficient concrete, by reviewing previously published work

Eco-efficient concrete using industrial wastes: a review

"Advanced Materials Forum VI ". ISBN 978-3-03785-493-8.Concrete is one of the most widely used construction materials in the world. However, the production of Portland cement as the essential constituent of concrete requires a considerable energy level. Also releases a significant amount of chemical carbon dioxide emissions and other greenhouse gases (GHGs) into the atmosphere. Global demand will increase almost 200 % by 2050 from 2010 levels. Thus, seeking an eco-efficient and sustainable concrete may be one of the main roles that the construction industry should play in sustainable construction. Portland cement can be partially replaced by cementitious and pozzolanic materials, especially those of industry by-products such as fly ash, GGBS, silica fume, ceramic waste powder and metamorphic rock dust from stone cutting industry. The aggregates are also conserved by replacing them with recycled or waste materials (among which recycled concrete), ceramic waste, postconsumer glass, and recycled tires. All of the previous alternatives are, currently, the most used. This paper summarizes current knowledge about eco-efficient concrete, by reviewing previously published work

Air lime mortars with vegetable fat addition: characteristics and research needs

Although history reveals that air lime mortars with added vegetable fat (ALVF) were used very often in the past, little knowledge about them survives to modern times. Little is known about the influence of fat addition on the mortars’ durability, and some details about their manufacture and application are completely unknown. Even less is understood about the mechanisms that explain the behavior of ALVF-based mortars that also contain pozzolans. This paper reviews current knowledge about the characteristics of ALVF-based mortars in order to highlight questions that must be addressed in future research

Considerations about the use of lime-cement mortars for render conservation purposes

Some investigations about conservation renders points out that Portland cement based mortars should be avoided and should be replaced by lime-pozzolan mortars. However, this type of mortar is still under investigation and the majority of Portuguese construction enterprises operating in the field of building conservation do not possess enough know-how about them. Besides the absolute rejection of the use of Portland cement based mortars even with just a minimum amount appears to be a dogmatic position that is not fully grounded in scientific terms. These facts can influence the decision about the material’s choice for conservation purposes, since in certain circumstances it may be preferable to apply blended mortars instead of an incorrect application of lime-pozzolan mortars

Mechanical performance of concrete with partial replacement of sand by sewage sludge ash

The production of sewage sludge from waste water treatment plants is increasing all over the world. Disposal of sewage sludge is a serious environmental problem. If we think of the areas needed for sludge ash disposal, we clearly understand the importance of reusing sewage sludge ash in concrete. This paper presents results related to the replacement of sand by sewage sludge ash. The sludge was characterized for chemical composition (XRF analysis), crystalline phases (XRD analysis) and pozzolanic activity. The effects of incineration on crystal phases of dry sludge were investigated. Two (W/C) ratios (0.55 and 0.45) and three sludge percentages (5%, 10% and 20%) by cement mass were used. The mechanical performance of SSAC at different curing ages (3, 7, 28 and 90 days) was assessed by means of mechanical tests. Results show that sewage sludge ash leads to a reduction in density and mechanical strength. Results also show that concrete with 20% of sewage sludge ash and W/C=0.45 has a 28 day compressive strength of almost 30MPa

Mechanical performance of concrete with partial replacement of sand by sewage sludge ash from incineration

"Advanced Materials Forum VI , vol. 730-732"The production of sewage sludge from waste water treatment plants is increasing all over the world. Disposal of sewage sludge ash is a serious environmental problem. If we think of the areas needed for sludge ash disposal, we clearly understand the importance of reusing sewage sludge ash in concrete. This paper presents results related to the replacement of sand by sewage sludge ash. The sludge was characterized for chemical composition (XRF analysis), crystalline phases (XRD analysis) and pozzolanic activity. The effects of incineration on crystal phases of dry sludge were investigated. Two (W/C) ratios (0.55 and 0.45) and three sludge percentages (5%, 10% and 20%) by cement mass were used. The mechanical performance of SSAC at different curing ages (3, 7, 28 and 90 days) was assessed by means of mechanical tests. Results show that sewage sludge ash leads to a reduction in density and mechanical strength. Results also show that concrete with 20% of sewage sludge ash and W/C=0.45 has a 28 day compressive strength of almost 30MPa