Evaluation of industrial by-products as sustainable pozzolanic materials in recycled aggregate concrete

The utilization of traditional supplementary cementitious materials (SCMs) has become more intense in the concrete industry due to their better long-term properties. This research evaluates the fresh and hardened properties of concrete that was developed using a high amount of recycled aggregate (RA) incorporated with sustainable SCMs. Rice husk ash (RHA), palm oil fuel ash (POFA) and palm oil clinker powder (POCP) were used as SCMs at 10%, 20% and 30% cement replacement levels to investigate their positive role in the performance of RA concrete. The results showed that the 10% replacement level of cement by RHA produced the highest strength at all ages tested. Although POFA and POCP were found to negatively affect the strengths at an early age, the hardened properties showed improvement after a relatively long curing time of 90 days. In addition, the targeted compressive strength of 30 MPa was achieved by using SCMs at levels up to 30%. Overall, the sustainable SCMs can reduce the quantity of cement required for concrete production, as well as reduce the conventional cement with the industrial by-products, which are considered as waste materials; thus, the concrete produced using up to 30% of SCMs as a replacement for cement could be considered as more environmentally-friendly concrete

Effect of aggressive chemicals on durability and microstructure properties of concrete containing crushed new concrete aggregate and non-traditional supplementary cementitious …

The increasing awareness and usage of traditional supplementary cementitious materials (SCMs) in concrete have pressured the construction industry to look for alternatives to overcome the concerns over their plentiful availability in the future. This research illustrates the performance of recycled aggregate concrete prepared with the incorporation of available industrial by-products, namely rice husk ash (RHA), palm oil fuel ash (POFA) and palm oil clinker powder (POCP) as alternatives for traditional SCMs. The effect of hydrochloric (HCl) acid and magnesium sulfate (MgSO 4) attack was evaluated by measuring the change in mass, compressive strength and microstructural analysis. The results revealed that the incorporation of RHA, POFA and POCP up to 30% minimizes concrete deterioration and loss in compressive strength when the specimens were exposed to HCl solution. In addition, the scanning electron

Assessment on engineering properties and CO2 emissions of recycled aggregate concrete incorporating waste products as supplements to Portland cement

This paper presents an experimental investigation on the durability properties and carbon dioxide (CO2) emissions of concrete developed using waste products. The concrete comprised of recycled concrete aggregate (RA) as a complete coarse aggregate replacement. In addition, rice husk ash (RHA), palm oil fuel ash (POFA) and palm oil clinker powder (POCP) were used as replacement materials for cement at levels up to 30%. The supplementary cementitious materials (SCMs) were used in RA concrete with the aim of reducing the dependency on cement as a stand-alone binder. The compressive strength, water absorption, chloride-ion penetration and electrical resistivity were investigated for RA concrete containing SCMs. Moreover, the residual compressive strength was also examined along with the weight loss to check the elevated temperature resistance of RA concrete with SCMs. The results revealed that

High volume cement replacement by environmental friendly industrial by-product palm oil clinker powder in cement – lime masonry mortar

Cement-lime based mortar is extremely popular for a wide range of construction around the world and conserving natural resources used in the production of such material is of capital importance. Identification of alternative materials from palm oil based industrial by-products enabled researchers to use palm oil clinker powder (POCP) as a cement replacement material; in this research work, POCP was used as cement replacement material in masonry mortar. The physical, chemical properties and SEM of POCP were analyzed to investigate the feasibility of utilizing POCP as cement replacement for up to 80%. Based on the feasibility study, final mortar mixes were prepared utilizing 40% of POCP. Further investigations were carried on fresh, mechanical and bond properties of mortar. The hardened properties for mechanical performance and ultrasonic pulse velocity (UPV) investigated in water and air cured regimes show that up to 40% of cement could be replaced to obtain the requisite compressive strength of 12.4 MPa for cement-lime mortar. Further, POCP ground to more number of cycles had minor impact on the mechanical properties. The investigation on the potential use of POCP as cement replacement confirmed the potentiality through energy saving, cost effective and cleaner environment

Assessment on engineering properties and CO2 emissions of recycled aggregate concrete incorporating waste products as supplements to Portland cement

This paper presents an experimental investigation on the durability properties and carbon dioxide (CO 2 ) emissions of concrete developed using waste products. The concrete comprised of recycled concrete aggregate (RA) as a complete coarse aggregate replacement. In addition, rice husk ash (RHA), palm oil fuel ash (POFA) and palm oil clinker powder (POCP) were used as replacement materials for cement at levels up to 30%. The supplementary cementitious materials (SCMs) were used in RA concrete with the aim of reducing the dependency on cement as a stand-alone binder. The compressive strength, water absorption, chloride-ion penetration and electrical resistivity were investigated for RA concrete containing SCMs. Moreover, the residual compressive strength was also examined along with the weight loss to check the elevated temperature resistance of RA concrete with SCMs. The results revealed that the use of 30% RHA as SCM produced the highest compressive strength efficiency of 0.143 MPa/kg cement among all mixes at the age of 90 days. In addition, a significant enhancement was observed for the durability-related properties at later ages, although the engineering properties of RA concrete containing SCMs was low at the age of 28 days. The thermogravimetric (TG) analysis indicated that the RHA is more effective as a pozzolanic additive than POFA and POCP. The CO 2 emissions from RA concrete were reduced by approximately 29% when it was incorporated with 30% SCM, where the eco-strength efficiency showed the highest values at 20% cement replacement level of 20%

Effect of aggressive chemicals on durability and microstructure properties of concrete containing crushed new concrete aggregate and non-traditional supplementary cementitious materials

The increasing awareness and usage of traditional supplementary cementitious materials (SCMs) in concrete have pressured the construction industry to look for alternatives to overcome the concerns over their plentiful availability in the future. This research illustrates the performance of recycled aggregate concrete prepared with the incorporation of available industrial by-products, namely rice husk ash (RHA), palm oil fuel ash (POFA) and palm oil clinker powder (POCP) as alternatives for traditional SCMs. The effect of hydrochloric (HCl) acid and magnesium sulfate (MgSO4) attack was evaluated by measuring the change in mass, compressive strength and microstructural analysis. The results revealed that the incorporation of RHA, POFA and POCP up to 30% minimizes concrete deterioration and loss in compressive strength when the specimens were exposed to HCl solution. In addition, the scanning electron microscopy image showed less propagation of micro-cracks caused by expansive ettringite in the case of MgSO4 attack. Further, the X-ray diffraction analysis indicated that RHA is more effective as pozzolanic additive than POFA and POCP. Overall, the RA-based concrete had significant enhancement in its performance against acid and sulfate attacks using alternative SCMs from industrial by-products