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A green roof is composed of a substrate and drainage layers which are fixed on insulation material and roof structure. The global heat resistance (Rc) within a green roof is affected by the humidity content of the substrate layer in which the coarse recycled materials can be used. Moreover, the utilization of recycled coarse aggregates such as incinerated municipal solid waste aggregate (IMSWA) for the drainage layer would be a promising solution, increasing the recycling of secondary resources and saving natural resources. Therefore, this paper aims to investigate the heat transfer across green roof systems with a drainage layer of IMSWA and a substrate layer including recycled tiles and bricks in wet and dry states according to ISO-conversion method. Based on the results, water easily flows through the IMSWAs with a size of 7 mm. Meanwhile, the Rc-value of the green roof system with the dry substrate (1.26 m2 K/W) was 1.7 times more than that of the green roof system with the unsaturated substrate (0.735 m2 K/W). This means that the presence of air-spaces in the dry substrate provided more heat resistance, positively contributing to heat transfer decrease, which is also dependent on the drainage effect of IMSWA. In addition, the Rc-value of the dry substrate layer was about twice that of IMSWA as the drainage layer. No significant difference was observed between the Rc-values of the unsaturated substrate layer and the IMSWA layer.
Mostafa Kazemi; Luc Courard; Julien Hubert. Heat Transfer Measurement within Green Roof with Incinerated Municipal Solid Waste Aggregates. Sustainability 2021, 13, 7115 .
AMA StyleMostafa Kazemi, Luc Courard, Julien Hubert. Heat Transfer Measurement within Green Roof with Incinerated Municipal Solid Waste Aggregates. Sustainability. 2021; 13 (13):7115.
Chicago/Turabian StyleMostafa Kazemi; Luc Courard; Julien Hubert. 2021. "Heat Transfer Measurement within Green Roof with Incinerated Municipal Solid Waste Aggregates." Sustainability 13, no. 13: 7115.
Fine recycled aggregates (FRA) (0/4 mm) are up to now not valorized on a high enough level because of characteristics like an elevated water absorption, higher fines content, and the presence of contaminations. Leftover gypsum residues from the construction site can cause internal sulfate attack when FRA are incorporated into new structures. Concern about this deteriorating reaction plays an important role in the rejection of FRA. In this study, samples of FRA from different recycling centers were characterized and incorporated into mortars. They were then subjected to swelling tests in order to evaluate the development of sulfate attack. Reference materials with different amounts of sulfates were used as a comparison. Results showed a variable sulfate content in industrial FRA, depending heavily on the source of the materials. In all but one case, the total amounts surpassed the acceptable sulfate contents specified in the European standard EN 206, meaning the FRA would be rejected for reuse in concrete. Nevertheless, swelling tests demonstrated that these contamination levels did not pose a risk for sulfate attack. These results indicated that the incorporation of FRA leads to acceptable mechanical performances and that the sulfate limit could be reviewed to be less strict.
Charlotte Colman; David Bulteel; Sébastien Rémond; Zengfeng Zhao; Luc Courard. Valorization of Fine Recycled Aggregates Contaminated with Gypsum Residues: Characterization and Evaluation of the Risk for Secondary Ettringite Formation. Materials 2020, 13, 4866 .
AMA StyleCharlotte Colman, David Bulteel, Sébastien Rémond, Zengfeng Zhao, Luc Courard. Valorization of Fine Recycled Aggregates Contaminated with Gypsum Residues: Characterization and Evaluation of the Risk for Secondary Ettringite Formation. Materials. 2020; 13 (21):4866.
Chicago/Turabian StyleCharlotte Colman; David Bulteel; Sébastien Rémond; Zengfeng Zhao; Luc Courard. 2020. "Valorization of Fine Recycled Aggregates Contaminated with Gypsum Residues: Characterization and Evaluation of the Risk for Secondary Ettringite Formation." Materials 13, no. 21: 4866.
Bernard Morino Ganou Koungang; Dieunedort Ndapeu; Jerôme Tchoufang Tchuindjang; Bernard Wenga Ntcheping; Gilbert Tchemou; Sophie Bistac; Ebénézer Njeugna; Luc Courard. Influence of temperature on the creep behaviour by macroindentation of Cocos nucifera shells and Canarium schweinfurthii cores (bio-shellnut wastes in Cameroon). Materials Research Express 2020, 7, 105306 .
AMA StyleBernard Morino Ganou Koungang, Dieunedort Ndapeu, Jerôme Tchoufang Tchuindjang, Bernard Wenga Ntcheping, Gilbert Tchemou, Sophie Bistac, Ebénézer Njeugna, Luc Courard. Influence of temperature on the creep behaviour by macroindentation of Cocos nucifera shells and Canarium schweinfurthii cores (bio-shellnut wastes in Cameroon). Materials Research Express. 2020; 7 (10):105306.
Chicago/Turabian StyleBernard Morino Ganou Koungang; Dieunedort Ndapeu; Jerôme Tchoufang Tchuindjang; Bernard Wenga Ntcheping; Gilbert Tchemou; Sophie Bistac; Ebénézer Njeugna; Luc Courard. 2020. "Influence of temperature on the creep behaviour by macroindentation of Cocos nucifera shells and Canarium schweinfurthii cores (bio-shellnut wastes in Cameroon)." Materials Research Express 7, no. 10: 105306.
This study investigated the engineering properties of compressed earth blocks (CEBs) stabilized with by-product binders: calcium carbide residue (CCR) and rice husk ash (RHA). The dry mixtures were prepared using the earthen material and 0–25 wt% CCR, firstly, and 20 wt% CCR partially substituted by the RHA (CCR:RHA in 20:0–12:8 ratios), secondly. The appropriate amount of water was thoroughly mixed with the dry mixtures. The moistened mixtures were manually compressed into CEBs, cured, dried, and tested. The stabilization of CEBs with CCR increased the dry compressive strength (CS) from 1.1 MPa with 0% CCR to 4.3 MPa with 10% CCR and above; decreased the bulk density (ρb:1800–1475 kg/m3) and increased the total porosity (TP:35–45%). This resulted in the improvement of the coefficient of structural efficiency (CSE: 610–3050 Pa∙m3/kg). It also improved the thermal efficiency given the decrease of the thermal conductivity (λ: 1.02–0.69 W/m∙K), thermal diffusivity (a: 6.3 × 10−7 to 4.7 × 10−7 m²/s) and thermal penetration depth (δp: 0.13–0.11 m). The RHA further improved the CS up to 7 MPa, reaching the optimum with 16:4 CCR:RHA (ρb: 1575 kg/m3 and TP: 40%). The latter reached higher CSE (4460 Pa∙m3/kg) than cement stabilized CEBs (3540 Pa∙m3/kg). It reached lower λ (0.64 w/m∙K), a (4.1 × 10−7 m²/s) and δp (0.11 m) than cement CEBs (1.01 w/m∙K, 6.8 × 10−7 m²/s, and 0.14 m). Additionally, the stabilization of CEBs with by-products improved the moisture sorption capacity. The improvement of the structural and thermal efficiency of CEBs by the stabilization with by-product binders is beneficial for load-bearing capacity and thermal performances in multi-storey buildings.
Philbert Nshimiyimana; Adamah Messan; Luc Courard. Physico-Mechanical and Hygro-Thermal Properties of Compressed Earth Blocks Stabilized with Industrial and Agro By-Product Binders. Materials 2020, 13, 3769 .
AMA StylePhilbert Nshimiyimana, Adamah Messan, Luc Courard. Physico-Mechanical and Hygro-Thermal Properties of Compressed Earth Blocks Stabilized with Industrial and Agro By-Product Binders. Materials. 2020; 13 (17):3769.
Chicago/Turabian StylePhilbert Nshimiyimana; Adamah Messan; Luc Courard. 2020. "Physico-Mechanical and Hygro-Thermal Properties of Compressed Earth Blocks Stabilized with Industrial and Agro By-Product Binders." Materials 13, no. 17: 3769.
Fine recycled aggregates are produced in large quantities when crushing Construction and Demolition Waste (C&DW). Even if coarse recycled aggregates are commonly used for road foundations, fine particles are often rejected as they are considered detrimental for the long-term behaviour of foundations. Physicochemical, mineralogical and mechanical characterizations (through X-ray diffraction, X-ray fluorescence, the chloride and sulphate contents, Los Angeles abrasion, micro-Deval resistance and static plate load tests) were performed on raw and treated fine recycled materials for understanding both the effects of the preparation, the compaction and the freeze–thaw cycles on the properties and the evolution of fine particles. Special attention was provided to the shape analysis of fines by means of image analyser. The results showed that the main characteristic parameters to be considered are the sieving curve and the proportion of grades. The mixes containing the highest quantity of fine particles, specifically lower than 63 µm, usually inducing a higher water demand and a higher capillary rise. This can be explained by specific surface and bluntness parameters which increase with the finer particles, inducing a higher surface roughness and, consequently, a higher potential interaction with water. Compaction did not seem to have a major effect on the production of fines (despite some breakdown occurred during compaction) and on the shape of materials (the bluntness and convexity increased slightly, while the elongation values remained similar after the compaction process). The static plate load tests showed that bearing capacity is slightly lower than the specifications for the road foundation after compaction. However, the studied material could meet the maximum criteria for secondary roads foundation construction on the wear resistance criteria. Recycled aggregates from C&DW without sufficient quality could be blended with other aggregates to enable their usage for upper-level road foundation.
Luc Courard; Mélanie Rondeux; Zengfeng Zhao; Frédéric Michel. Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base. Materials 2020, 13, 2994 .
AMA StyleLuc Courard, Mélanie Rondeux, Zengfeng Zhao, Frédéric Michel. Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base. Materials. 2020; 13 (13):2994.
Chicago/Turabian StyleLuc Courard; Mélanie Rondeux; Zengfeng Zhao; Frédéric Michel. 2020. "Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base." Materials 13, no. 13: 2994.
The aim of this work was to study the influence of the type of activator on the formulation of modified fly ash based geopolymer mortars. Geopolymer and alkali-activated materials (AAM) were made from fly ashes derived from coal and biomass combustion in thermal power plants. Basic activators (NaOH, CaO, and Na2SiO3) were mixed with fly ashes in order to develop binding properties other than those resulting from the use of Portland cement. The results showed that the mortars with 5 mol/dm3 of NaOH and 100 g of Na2SiO3 (N5-S22) gave a greater compressive strength than other mixes. The compressive strengths of analyzed fly ash mortars with activators N5-S22 and N5-C10 (5 mol/dm3 NaOH and 10% CaO) varied from 14.3 MPa to 5.9 MPa. The better properties of alkali-activated mortars with regular fly ash were influenced by a larger amount of amorphous silica and alumina phases. Scanning electron microscopy and calorimetry analysis provided a better understanding of the observed mechanisms.
Piotr Prochon; Zengfeng Zhao; Luc Courard; Tomasz Piotrowski; Frédéric Michel; Andrzej Garbacz. Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars. Materials 2020, 13, 1033 .
AMA StylePiotr Prochon, Zengfeng Zhao, Luc Courard, Tomasz Piotrowski, Frédéric Michel, Andrzej Garbacz. Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars. Materials. 2020; 13 (5):1033.
Chicago/Turabian StylePiotr Prochon; Zengfeng Zhao; Luc Courard; Tomasz Piotrowski; Frédéric Michel; Andrzej Garbacz. 2020. "Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars." Materials 13, no. 5: 1033.
Limestone has been successfully used as a constituent of cement and concrete for decades. Fine limestone is commonly included in Portland cement by intergrinding, resulting in an optimal particle size distribution of the modified cement. In other applications, limestone powder is added separately from cement, for producing more stable and robust mixes, especially self-compacting concrete. This chapter examines the performance of limestone modified Portland cement and concrete. The review comprises the effects on cement hydration in relation with the fineness of the limestone, on the fresh properties of mortar and concrete (including its role in self-compacting concrete), and on the strength development in the hardened state. Complementarily, comments regarding sulphate attack and environmental benefits of the use of limestone modified cement are included. Limestone is an effective constituent of cement and concrete, and comparative analyses should always be made to mixes produced to the same strength. In this way, it has to be regarded as a supplementary cementitious material when included by intergrinding with cement clinker, or as a filler when added separately to concrete.
Luc Courard; Duncan Herfort; Yury Villagrán. Limestone Powder. Bio-aggregates Based Building Materials 2017, 123 -151.
AMA StyleLuc Courard, Duncan Herfort, Yury Villagrán. Limestone Powder. Bio-aggregates Based Building Materials. 2017; ():123-151.
Chicago/Turabian StyleLuc Courard; Duncan Herfort; Yury Villagrán. 2017. "Limestone Powder." Bio-aggregates Based Building Materials , no. : 123-151.