The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform

Chi Sun Poon - One of the best experts on this subject based on the ideXlab platform.

  • enhancing the accelerated carbonation of recycled Concrete aggregates by using reclaimed wastewater from Concrete Batching plants
    Construction and Building Materials, 2020
    Co-Authors: Xiaoliang Fang, Baojian Zhan, Chi Sun Poon
    Abstract:

    Abstract Accelerated carbonation is regarded as an efficient and economical way to improve the mechanical properties of recycled Concrete aggregates (RCAs) through strengthening the attached mortar/cement paste. However, the property enhancement is usually limited due to the pore-filling effect at the surface of the attached mortar/cement paste. In this study, a series of pretreatment methods were employed on both laboratory prepared cement pastes and real RCA samples to enhance the accelerated carbonation process. This involved the use of a saturated Ca(OH)2 solution and wastewater generated from a ready-mixed Concrete plant. The hypothesis was that with the additional introduction of Ca2+ and OH− into RCAs through either soaking or spraying, the carbonation products can be enriched. The physico-chemical and microstructural properties of the samples were investigated by using mercury intrusion porosimetry (MIP), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) analysis, microhardness, scanning electron microscopy (SEM)-back scattered electron (BSE) imaging techniques. Moreover, the density and water absorption values of the samples were evaluated. The experimental results showed that the properties of both the cement paste and RCA samples were further improved with the use of the pretreatment methods before carbonation.

  • management and sustainable utilization of processing wastes from ready mixed Concrete plants in construction a review
    Resources Conservation and Recycling, 2018
    Co-Authors: Dongxing Xuan, Chi Sun Poon, Wei Zheng
    Abstract:

    Abstract Increasing attention is now paid to sustainable waste management from construction due to the increasing disposal cost as well as the growing public appreciation on environmental impacts. Since 1990′s, recycling and reuse of hardened Concrete from construction and demolition waste has received considerable attention, while the principles, methods of treatment and associated technologies developed are generally not applicable to unhardened or early hardened Concrete wastes generated during Concrete production processes. This review focuses on the source, classification and management of the processing wastes from ready-mixed Concrete (RMC) plants and their potential reutilization. In recent years, washing-out systems have been adopted at many Concrete Batching plants. Depending on reclaiming systems such as aggregate and water reclaimers, the wastes generated are classified as reclaimed aggregates, Concrete slurry waste, wastewater and reclaimed water. Although the potential to reuse these wastes has attracted lots of interest, the respective principles and methods of treatments have only been reported in discretely, and sometimes inconclusive manners. The management challenges such as low re-usage rate, poor product performance, increasing cost and strict local regulations obviously limit their sustainable utilization. In order to minimize the dispose of the processing wastes from the RMC plants, the installation of both mechanical aggregate and water reclaiming systems are found to be necessary. All kinds of processing wastes can then be reused in producing different low carbon footprint products in order to improve the sustainable development of the RMC industry.

Solomon O. O. - One of the best experts on this subject based on the ideXlab platform.

  • Compressive strength analysis of conventional design Concrete mix ratio; 1:2:4 and non-conventional Concrete mix ratio; 1:3:3 for the construction industry in Nigeria
    'Research Gateway Society', 2019
    Co-Authors: Ramonu, John A. L., Ilevbaoje J. O., Olaonipekun O. A., Sina-olulana Opeyemi, Dotun O., Adekunle S. S., Modupe A. E., Atoyebi O. D., Solomon O. O.
    Abstract:

    The challenge which is very common in Nigeria construction industry is the coarse nature of 1:2:4 conventional mix ratio of green Concrete. Most often in Nigeria construction industry, the 1:2:4 conventional mix ratio is often been rationalised and batch to obtain 1:3:3 mix ratio so as to have a workable green Concrete. This is often preferable due to the challenge arising from inability of the quarry industry to crush stone 10mm, 12mm, 14mm and 20mm size separately. What is common in many part of this Country is manual crush aggregate, which is hand crush aggregate which are the combination of 10mm, 12mm, 14mm and 20mm, which lead to the difficulty in Concrete Batching with 1:2:4 mix ratio. This research came from the challenge encountered during the construction of Oba Abegunde Adukanjemeji Monument Dynast, Omu Aran, in getting machine crush aggregate, For the purpose of this research work, the compressive strength of Concrete made of conventional mix ratio (1:2:4) and Concrete made of non-conventional mix ratio 1:3:3 was investigated. Combination of 10mm, 12mm, 14mm and 20mm size of coarse aggregate was use to cast Concrete made of 1:2:4 mix ratio and 1:3:3 mix ratio. The Concrete cube of size (150mmx150mmx150mm) made from 1:2:4 mix ratio serve as the control and was cured in a curing tank which was monitored for 7days, 14days and 28days respectively. Also Concrete cube made of 1:3:3 mix ratio was also cast and cured for 7days, 14days and 28days respectively. From the result of the average compressive strength of Concrete made of 1:3:3 mix ratio, at twenty eight days of curing gives(16N/mm2 ), which shows that, the Concrete strength met the minimum required standard for twenty eight days of curing which is (15N/mm2 ) while 1:2:4 mix ratio using the same aggregate and curing period gives (17N/mm2 ) Also a statistical test (Analysis of variance, ANOVA) on the data gotten was introduced in which a null hypothesis and alternative hypothesis was proposed, and the null hypothesis was accepted as a result of the asymptotic significance value gotten to be (0.923). This shows that 2 there is no significant difference between Concrete made of 1:2:4 mix ratio and the one made from 1:3:3 mix ratio Keywords: Coarse Aggregates, Compressive Strength, Concrete, Aggregate Sizes, Fineness Modulus (FM), conventional mix ratio, non-conventional mix ratio and Statistical Test (ANOVA

  • COMPRESSIVE STRENGTH ANALYSIS OF CONVENTIONAL DESIGN Concrete MIX RATIO; 1:2:4 AND NON-CONVENTIONAL CONCETE MIX RATIO; 1:3:3 FOR THE CONSTRUCTION INDUSTRY IN NIGERIA
    2019
    Co-Authors: Ramonu J.a., Olaonipekun O. A., Sina-olulana Opeyemi, Adekunle S. S., Modupe A. E., Atoyebi O. D., Ilevbaoje J.o., Onikanni D., Solomon O. O.
    Abstract:

    The challenge which is very common in Nigeria construction industry is the coarse nature of 1:2:4 conventional mix ratio of green Concrete. Most often in Nigeria construction industry, the 1:2:4 conventional mix ratio is often been rationalised and batch to obtain 1:3:3 mix ratio so as to have a workable green Concrete. This is often preferable due to the challenge arising from inability of the quarry industry to crush stone 10mm, 12mm, 14mm and 20mm size separately. What is common in many part of this Country is manual crush aggregate, which is hand crush aggregate which are the combination of 10mm, 12mm, 14mm and 20mm, which lead to the difficulty in Concrete Batching with 1:2:4 mix ratio. This research came from the challenge encountered during the construction of Oba Abegunde Adukanjemeji Monument Dynast, Omu Aran, in getting machine crush aggregate, For the purpose of this research work, the compressive strength of Concrete made of conventional mix ratio (1:2:4) and Concrete made of non-conventional mix ratio 1:3:3 was investigated. Combination of 10mm, 12mm, 14mm and 20mm size of coarse aggregate was use to cast Concrete made of 1:2:4 mix ratio and 1:3:3 mix ratio. The Concrete cube of size (150mmx150mmx150mm) made from 1:2:4 mix ratio serve as the control and was cured in a curing tank which was monitored for 7days, 14days and 28days respectively. Also Concrete cube made of 1:3:3 mix ratio was also cast and cured for 7days, 14days and 28days respectively. From the result of the average compressive strength of Concrete made of 1:3:3 mix ratio, at twenty eight days of curing gives(16N/mm2 ), which shows that, the Concrete strength met the minimum required standard for twenty eight days of curing which is (15N/mm2 ) while 1:2:4 mix ratio using the same aggregate and curing period gives (17N/mm2 ) Also a statistical test (Analysis of variance, ANOVA) on the data gotten was introduced in which a null hypothesis and alternative hypothesis was proposed, and the null hypothesis was accepted as a result of the asymptotic significance value gotten to be (0.923). This shows that 2 there is no significant difference between Concrete made of 1:2:4 mix ratio and the one made from 1:3:3 mix ratio Keywords: Coarse Aggregates, Compressive Strength, Concrete, Aggregate Sizes, Fineness Modulus (FM), conventional mix ratio, non-conventional mix ratio and Statistical Test (ANOVA

Wei Zheng - One of the best experts on this subject based on the ideXlab platform.

  • management and sustainable utilization of processing wastes from ready mixed Concrete plants in construction a review
    Resources Conservation and Recycling, 2018
    Co-Authors: Dongxing Xuan, Chi Sun Poon, Wei Zheng
    Abstract:

    Abstract Increasing attention is now paid to sustainable waste management from construction due to the increasing disposal cost as well as the growing public appreciation on environmental impacts. Since 1990′s, recycling and reuse of hardened Concrete from construction and demolition waste has received considerable attention, while the principles, methods of treatment and associated technologies developed are generally not applicable to unhardened or early hardened Concrete wastes generated during Concrete production processes. This review focuses on the source, classification and management of the processing wastes from ready-mixed Concrete (RMC) plants and their potential reutilization. In recent years, washing-out systems have been adopted at many Concrete Batching plants. Depending on reclaiming systems such as aggregate and water reclaimers, the wastes generated are classified as reclaimed aggregates, Concrete slurry waste, wastewater and reclaimed water. Although the potential to reuse these wastes has attracted lots of interest, the respective principles and methods of treatments have only been reported in discretely, and sometimes inconclusive manners. The management challenges such as low re-usage rate, poor product performance, increasing cost and strict local regulations obviously limit their sustainable utilization. In order to minimize the dispose of the processing wastes from the RMC plants, the installation of both mechanical aggregate and water reclaiming systems are found to be necessary. All kinds of processing wastes can then be reused in producing different low carbon footprint products in order to improve the sustainable development of the RMC industry.

Xiaoliang Fang - One of the best experts on this subject based on the ideXlab platform.

  • enhancing the accelerated carbonation of recycled Concrete aggregates by using reclaimed wastewater from Concrete Batching plants
    Construction and Building Materials, 2020
    Co-Authors: Xiaoliang Fang, Baojian Zhan, Chi Sun Poon
    Abstract:

    Abstract Accelerated carbonation is regarded as an efficient and economical way to improve the mechanical properties of recycled Concrete aggregates (RCAs) through strengthening the attached mortar/cement paste. However, the property enhancement is usually limited due to the pore-filling effect at the surface of the attached mortar/cement paste. In this study, a series of pretreatment methods were employed on both laboratory prepared cement pastes and real RCA samples to enhance the accelerated carbonation process. This involved the use of a saturated Ca(OH)2 solution and wastewater generated from a ready-mixed Concrete plant. The hypothesis was that with the additional introduction of Ca2+ and OH− into RCAs through either soaking or spraying, the carbonation products can be enriched. The physico-chemical and microstructural properties of the samples were investigated by using mercury intrusion porosimetry (MIP), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) analysis, microhardness, scanning electron microscopy (SEM)-back scattered electron (BSE) imaging techniques. Moreover, the density and water absorption values of the samples were evaluated. The experimental results showed that the properties of both the cement paste and RCA samples were further improved with the use of the pretreatment methods before carbonation.

Dongxing Xuan - One of the best experts on this subject based on the ideXlab platform.

  • management and sustainable utilization of processing wastes from ready mixed Concrete plants in construction a review
    Resources Conservation and Recycling, 2018
    Co-Authors: Dongxing Xuan, Chi Sun Poon, Wei Zheng
    Abstract:

    Abstract Increasing attention is now paid to sustainable waste management from construction due to the increasing disposal cost as well as the growing public appreciation on environmental impacts. Since 1990′s, recycling and reuse of hardened Concrete from construction and demolition waste has received considerable attention, while the principles, methods of treatment and associated technologies developed are generally not applicable to unhardened or early hardened Concrete wastes generated during Concrete production processes. This review focuses on the source, classification and management of the processing wastes from ready-mixed Concrete (RMC) plants and their potential reutilization. In recent years, washing-out systems have been adopted at many Concrete Batching plants. Depending on reclaiming systems such as aggregate and water reclaimers, the wastes generated are classified as reclaimed aggregates, Concrete slurry waste, wastewater and reclaimed water. Although the potential to reuse these wastes has attracted lots of interest, the respective principles and methods of treatments have only been reported in discretely, and sometimes inconclusive manners. The management challenges such as low re-usage rate, poor product performance, increasing cost and strict local regulations obviously limit their sustainable utilization. In order to minimize the dispose of the processing wastes from the RMC plants, the installation of both mechanical aggregate and water reclaiming systems are found to be necessary. All kinds of processing wastes can then be reused in producing different low carbon footprint products in order to improve the sustainable development of the RMC industry.