Periodic Reporting for period 1 - TRAC (Tailor-made Recycled Aggregate Concretes)
Periodo di rendicontazione: 2018-07-01 al 2020-06-30
The scientific objectives (SO) are to investigate:
SO1. Micro and macro-mechanical properties & to develop statistical analysis models for RCA. It is achieved with 100% completion.
SO2. Testing methods for RCA. It is achieved with 100% completion.
SO3. Microstructure of RACs. It is achieved with 100% completion.
SO4. Influence of RCA on the properties of RACs. It is achieved with 100% completion.
SO5. Interactions of RCAs with various SCMs. It is achieved with 100% completion.
SO6. Durability properties of RACs and to develop theoretical analysis models to describe the transport behaviour of RACs. It is on-going with 10% completion.
SO7. Fire behaviour of RACs and to develop predictive models for fire resistance calculations. It is on-going with 5% completion.
SO8. Cost-benefit financial analysis models for the use of RCA in concrete. It is not started yet.
SO9. Design guidelines for the mix processes of RACs. It is not started yet.
The general objectives (GO) are:
GO1. Draw together teams with diverse skills and expertise. It is on-going with 90% completion.
GO2. Build joint collaborative projects for RACs and structures. It is on-going with 60% completion.
GO3. Create a platform for research training and the transfer of knowledge activities. It is on-going with 40% completion.
GO4. Disseminate knowledge to the larger international community. It is on-going with 50% completion.
GO5. Provide intensive training-through-research programmes as well as the training in complementary skills. It is on-going with 50% completion.
GO6. Establish collaborative mechanisms for long-term partnerships between EU and Asian researchers and institutes. It is on-going with 50% completion.
SO1. Micro and macro-mechanical properties & to develop statistical analysis models for RCA. It is achieved with 100% completion.
SO2. Testing methods for RCA. It is achieved with 100% completion.
SO3. Microstructure of RACs. It is achieved with 100% completion.
SO4. Influence of RCA on the properties of RACs. It is achieved with 100% completion.
SO5. Interactions of RCAs with various SCMs. It is achieved with 100% completion.
SO6. Durability properties of RACs and to develop theoretical analysis models to describe the transport behaviour of RACs. It is on-going with 10% completion.
SO7. Fire behaviour of RACs and to develop predictive models for fire resistance calculations. It is on-going with 5% completion.
SO8. Cost-benefit financial analysis models for the use of RCA in concrete. It is not started yet.
SO9. Design guidelines for the mix processes of RACs. It is not started yet.
The general objectives (GO) are:
GO1. Draw together teams with diverse skills and expertise. It is on-going with 90% completion.
GO2. Build joint collaborative projects for RACs and structures. It is on-going with 60% completion.
GO3. Create a platform for research training and the transfer of knowledge activities. It is on-going with 40% completion.
GO4. Disseminate knowledge to the larger international community. It is on-going with 50% completion.
GO5. Provide intensive training-through-research programmes as well as the training in complementary skills. It is on-going with 50% completion.
GO6. Establish collaborative mechanisms for long-term partnerships between EU and Asian researchers and institutes. It is on-going with 50% completion.
During PR1 the research has been mainly on the material characterisation of RCAs and RACs (WP2), the RACs with SCMs (WP3), and its durability performance (WP4). The work performed covers:
1. The macro characteristics of RCA (D2.1&D2.2)
2. The microstructures of ITZs (D2.1&D2.2)
3. The workability and the rheological properties of fresh RACs, with and without SCMs (D3.1&D3.2)
4. The mechanical properties of hardened RACs, with and without SCMs (D3.1&D3.2)
5. The transport properties of RACs (to be reported in D4.1)
The research findings have been reported by 16 peer-reviewed journal papers, of which 13 acknowledged EU funding. The main findings are:
• Adding extra water or alkaline solution for a similar workability will decrease the mechanical strength of the mortar, and thus this is not a good way to application of RFA in concrete.
• The weakest ITZ is the one between the new paste and RLWA covered with old paste and the strongest ITZ is the one between new paste and RLWA without old paste.
• The addition of 1-2% Chinese RA or 20% Chinese RFA in the cementitious mortar does not impair the compressive strength, and the addition of 30% RLWA in concrete can keep the similar or even higher compressive strength compared with the reference concrete.
• The addition of up to 20% Chinese RFA in the cementitious mortar does not increase the dry shrinkage.
• The RAC specimens have shown similar failure characteristics regardless of monotonic or cyclic loading.
• To achieve the targeted flow slump of SCC, the FDW replacement of up to 50%wt increases the superplasticizer requirement more than the control SCC and SCC mixed with RHA while decreasing the fresh density compared to the control SCC.
• The use of FDW considerably increases the V-funnel flow time. The RHA-SCC mixture containing FDW increases the flow time while decreasing the slump flow loss.
• At the cementitious content of 450 kg/m3 and 0.35-w/c the SCC with 10%wt the RHA has noticeable blocking, whereas those at 650 kg/m3 with 10 and 20%wt. RHA have no noticeable blocking.
• SCC containing RHA and FDW has higher compressive and splitting tensile strengths than that the control SCC. The 10% RHA-SCC with 30%wt FDW achieves the highest strength
• The addition of gypsum in mixes with 100% slag has no clear effect on the hydration process, whilst the addition of gypsum in mixes with 80% slag and 20% cement significantly changed the hydration process and accelerated the formation of solid network in the matrix.
1. The macro characteristics of RCA (D2.1&D2.2)
2. The microstructures of ITZs (D2.1&D2.2)
3. The workability and the rheological properties of fresh RACs, with and without SCMs (D3.1&D3.2)
4. The mechanical properties of hardened RACs, with and without SCMs (D3.1&D3.2)
5. The transport properties of RACs (to be reported in D4.1)
The research findings have been reported by 16 peer-reviewed journal papers, of which 13 acknowledged EU funding. The main findings are:
• Adding extra water or alkaline solution for a similar workability will decrease the mechanical strength of the mortar, and thus this is not a good way to application of RFA in concrete.
• The weakest ITZ is the one between the new paste and RLWA covered with old paste and the strongest ITZ is the one between new paste and RLWA without old paste.
• The addition of 1-2% Chinese RA or 20% Chinese RFA in the cementitious mortar does not impair the compressive strength, and the addition of 30% RLWA in concrete can keep the similar or even higher compressive strength compared with the reference concrete.
• The addition of up to 20% Chinese RFA in the cementitious mortar does not increase the dry shrinkage.
• The RAC specimens have shown similar failure characteristics regardless of monotonic or cyclic loading.
• To achieve the targeted flow slump of SCC, the FDW replacement of up to 50%wt increases the superplasticizer requirement more than the control SCC and SCC mixed with RHA while decreasing the fresh density compared to the control SCC.
• The use of FDW considerably increases the V-funnel flow time. The RHA-SCC mixture containing FDW increases the flow time while decreasing the slump flow loss.
• At the cementitious content of 450 kg/m3 and 0.35-w/c the SCC with 10%wt the RHA has noticeable blocking, whereas those at 650 kg/m3 with 10 and 20%wt. RHA have no noticeable blocking.
• SCC containing RHA and FDW has higher compressive and splitting tensile strengths than that the control SCC. The 10% RHA-SCC with 30%wt FDW achieves the highest strength
• The addition of gypsum in mixes with 100% slag has no clear effect on the hydration process, whilst the addition of gypsum in mixes with 80% slag and 20% cement significantly changed the hydration process and accelerated the formation of solid network in the matrix.
The proposed research work listed above is intended to overcome current barriers of using RCA in concrete for structural applications and to bridge the knowledge gap between scientists and engineers.The novelty of the proposed research exchange is to develop common approaches which can be used for a wide range of recycled aggregate concrete products. By developing collaborative multi- and inter-disciplinary research we can improve our knowledge, skills, and experiences more effectively and more efficiently. Not only can this reduce the cost of the research but can also speed it up and disseminate the research findings more quickly and more widely, thus to achieve a multi-win scenario. In many cities, particularly in many developing countries, old buildings are being demolished and new ones are being constructed. From an environmental and cost savings standpoint, it is very logical to take waste from on site and reuse it in a new project. The proposed research is extremely timely and important to advance innovation in sustainable construction materials to be applied in infrastructure development, providing a robust scientific underpinning for the design of recycled aggregate concrete mix based on its applications, considering the current shortage of virgin aggregate in many countries. The research will also contribute to the development of the modelling tools required to resolve uncertainties in the parameters influencing the long-term performance of recycled aggregate concrete structures, enabling the safe and confident utilisation of RCA in infrastructure applications in the Europe and worldwide.
The exchange programme provided by this RISE project has offered a great opportunity for researchers, particularly young researchers, to develop their skills and gain experience in the fields that are likely to drive concrete research over the next decade. It helped them to develop the international contacts necessary for a successful long-term career, and prepare them for making use of new facilities and new tools available in the world. The program also allowed individual partners to take advantage of the skills of talented researchers from highly respected research institutions both inside and outside Europe and to learn from their experiences.
The project so far involved 19 researchers. Most of them are PhD research students or early career researchers. As the outcomes of this project, TDTU has been awarded for two new research grants. One is funded by Vietnamese National Foundation for Science and Technology Development to research “Utilization of agricultural waste in production of sustainable construction materials” for two years (2020-22) with 600 million VND. The other is funded by Germany Federal Ministry of Education and Research, for a “German-Vietnamese Collaborative Project on Resource-efficient Construction using Sustainable Building Materials” from 7/2020 to 6/2024 with a funding of 1100 million VND.
The exchange programme provided by this RISE project has offered a great opportunity for researchers, particularly young researchers, to develop their skills and gain experience in the fields that are likely to drive concrete research over the next decade. It helped them to develop the international contacts necessary for a successful long-term career, and prepare them for making use of new facilities and new tools available in the world. The program also allowed individual partners to take advantage of the skills of talented researchers from highly respected research institutions both inside and outside Europe and to learn from their experiences.
The project so far involved 19 researchers. Most of them are PhD research students or early career researchers. As the outcomes of this project, TDTU has been awarded for two new research grants. One is funded by Vietnamese National Foundation for Science and Technology Development to research “Utilization of agricultural waste in production of sustainable construction materials” for two years (2020-22) with 600 million VND. The other is funded by Germany Federal Ministry of Education and Research, for a “German-Vietnamese Collaborative Project on Resource-efficient Construction using Sustainable Building Materials” from 7/2020 to 6/2024 with a funding of 1100 million VND.