The Experts below are selected from a list of 9429 Experts worldwide ranked by ideXlab platform
Hockin H K Xu - One of the best experts on this subject based on the ideXlab platform.
-
Injectable calcium Phosphate Cement: effects of powder-to-liquid ratio and needle size.
Journal of Biomedical Materials Research Part B, 2008Co-Authors: Elena F. Burguera, Hockin H K XuAbstract:Calcium Phosphate Cement (CPC) sets in situ and forms apatite with excellent osteoconductivity and bone-replaCement capability. The objectives of this study were to formulate an injectable tetracalcium Phosphate-dicalcium Phosphate Cement (CPCD), and investigate the powder/liquid ratio and needle-size effects. The injection force (mean ± SD; n = 4) to extrude the paste increased from (8 ± 2) N using a 10-gauge needle to (144 ± 17) N using a 21-gauge needle (p < 0.05). With the 10-gauge needle, the mass percentage of extruded paste was (95 ± 4)% at a powder/liquid ratio of 3; it decreased to (70 ± 12)% at powder/liquid = 3.5 (p < 0.05). A relationship was established between injection force, F, and needle lumen cross-sectional area, A: F = 5.0 + 38.7/A0.8. Flexural strength, S, (mean ± SD; n = 5) increased from (5.3 ± 0.8) MPa at powder/liquid = 2 to (11.0 ± 0.8) MPa at powder/liquid = 3.5 (p < 0.05). Pore volume fraction, P, ranged from 62.4% to 47.9%. A relationship was established: S = 47.7 × (1 - P)2.3. The strength of the injectable CPCD matched/exceeded the reported strengths of sintered porous hydroxyapatite implants that required machining. The novel injectable CPCD with a relatively high strength may be useful in filling defects with limited accessibility such as periodontal repair and tooth root-canal fillings, and in minimally-invasive techniques such as percutaneous vertebroplasty to fill the lesions and to strengthen the osteoporotic bone.
-
injectable and macroporous calcium Phosphate Cement scaffold
Biomaterials, 2006Co-Authors: Hockin H K Xu, Elena F. Burguera, Michael D Weir, Alexis M FraserAbstract:Calcium Phosphate Cement (CPC) can be molded and self-hardens in vivo to form resorbable hydroxyapatite with excellent osteoconductivity. The objective of this study was to develop an injectable, macroporous and strong CPC, and to investigate the effects of porogen and absorbable fibers. Water-soluble mannitol was used as porogen and mixed with CPC at mass fractions from 0% to 50%. CPC with 0–40% mannitol was fully extruded under a syringe force of 10 n. The paste with 50% mannitol required a 100-N force which extruded only 66% of the paste. At fiber volume fraction of 0–5%, the paste was completely extruded. However, at 6% and 7.5% fibers, some fibers were left in the syringe after the paste was extruded. The injectable CPC scaffold had a flexural strength (mean±sd; n=5n=5) of (3.2±1.0) MPa, which approached the reported strengths for sintered porous hydroxyapatite implants and cancellous bone. In summary, the injectability of a ceramic scaffold, a macroporous CPC, was studies for the first time. Processing parameters were tailored to achieve high injectability, macroporosity, and strength. The injectable and strong CPC scaffold may be useful in surgical sites that are not freely accessible by open surgery or when using minimally invasive techniques.
-
reinforCement of a self setting calcium Phosphate Cement with different fibers
Journal of Biomedical Materials Research, 2000Co-Authors: Hockin H K Xu, Frederick C Eichmiller, Anthony A GiuseppettiAbstract:A water-based calcium Phosphate Cement (CPC) has been used in a number of medical and dental procedures due to its excellent osteoconductivity and bone replaCement capability. However, the low tensile strength of CPC prohibits its use in many unsupported defects and stress-bearing locations. Little investigation has been carried out on the fiber reinforCement of CPC. The aims of the present study, therefore, were to examine whether fibers would strengthen CPC, and to investigate the effects of fiber type, fiber length, and volume fraction. Four different fibers were used: aramid, carbon, E-glass, and polyglactin. Fiber length ranged from 3–200 mm, and fiber volume fraction ranged from 1.9–9.5%. The fibers were mixed with CPC paste and placed into molds of 3 × 4 × 25 mm. A flexural test was used to fracture the set specimens and to measure the ultimate strength, work-of-fracture, and elastic modulus. Scanning electron microscopy was used to examine specimen fracture surfaces. Fiber type had significant effects on composite properties. The composite ultimate strength in MPa (mean ± SD; n = 6) was (62 ± 16) for aramid, (59 ± 11) for carbon, (29 ± 8) for E-glass, and (24 ± 4) for polyglactin, with 5.7% volume fraction and 75 mm fiber length. In comparison, the strength of unreinforced CPC was (13 ± 3). Fiber length also played an important role. For composites containing 5.7% aramid fibers, the ultimate strength was (24 ± 3) for 3 mm fibers, (36 ± 13) for 8 mm fibers, (48 ± 14) for 25 mm fibers, and (62 ± 16) for 75 mm fibers. At 25 mm fiber length, the ultimate strength of CPC composite was found to be linearly proportional to fiber strength. In conclusion, a self-setting calcium Phosphate Cement was substantially strengthened via fiber reinforCement. Fiber length, fiber volume fraction, and fiber strength were found to be key microstructural parameters that controlled the mechanical properties of CPC composites. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 52, 107–114, 2000.
John A. Jansen - One of the best experts on this subject based on the ideXlab platform.
-
stabilizing dental implants with a fiber reinforced calcium Phosphate Cement an in vitro and in vivo study
Acta Biomaterialia, 2020Co-Authors: Sonia De Lacerda Schickert, John A. Jansen, Ewald M Bronkhorst, Jeroen J J P Van Den Beucken, Sander C G LeeuwenburghAbstract:Abstract Stabilization of dental implants by means of biomaterials such as bioceramic granules and Cements is currently compromised by the poor mechanical properties of these bioceramics. Recently, our group developed a calcium Phosphate Cement reinforced with poly(vinyl alcohol) fibers with improved flexural strength and toughness. Herein we evaluated the capacity of these fiber-reinforced calcium Phosphate Cements to stabilize dental implants in vitro and in vivo using a range of mechanical and biological test methods. In vitro, filling of circumferential crestal peri‑implant bone defects with synthetic bone analogues with fiber-reinforced calcium Phosphate Cement demonstrated superior implant stability as compared to fiber-free calcium Phosphate Cement over a 12-week period. Similarly, filling of circumferential crestal peri‑implant bone defects with fiber-reinforced calcium Phosphate Cement effectively stabilized dental implants installed in a rabbit femoral condyle defect as assessed via both Implant Stability Quotient (ISQ) and torque-out measurements. Moreover, histological and histomorphometric evaluation demonstrated the osteocompatibility of fiber-reinforced calcium Phosphate Cement, as evidenced by absence of soft tissue ingrowth, direct contact between the bone and Cement, and gradual degradation of the biomaterial and replaCement by newly-formed bone. These data demonstrate that fiber-reinforced calcium Phosphate Cement stabilize dental implants during osseointegration. Statement of significance Dental implants can be placed immediately after a tooth is removed. However, in some cases the implant might not have enough bone surrounding it and becomes loose. To solve this, bioceramics have been used to fill the implant-bone gap. However, these materials have poor mechanical properties and are often not capable to stabilize the implant. Recently, our research group developed a new bone Cement that is reinforced with fibers and has, therefore, enhanced mechanical properties. In this study, we have proven that by molding this Cement into the implant-bone gap, we stabilize the implant and allow for a direct connection between the implant and the surrounding bone. Using this innovative Cement is therefore a safe and efficient way of stabilizing dental implants.
-
injectable calcium Phosphate Cement as a bone graft material around peri implant dehiscence defects a dog study source
International Journal of Oral & Maxillofacial Implants, 2008Co-Authors: Volkan Arisan, John A. Jansen, Tayfun Ozdemir, Ata Anil, Kursat OzerAbstract:Purpose: Peri-implant dehiscence defects occur frequently after dental implant plaCement. Various graft materials and techniques are proposed for treatment. In this study, an injectable calcium Phosphate Cement (Augmentech, Wetzlar, Germany) applied to a peri-implant defect was investigated. Materials and Methods: Standardized buccal dehiscence defects (5.8 3.8 mm) were surgically created after implant site preparation in the right proximal tibiae of 5 beagle dogs. Fifteen stepped cylindrical implants (13 3.8 mm diameter) were inserted (3 per dog), and Augmentech injectable calcium Phosphate Cement was injected into the dehiscences. The bone at the distal side of the implant was left intact to serve as a control. Postsurgically, each dog received double staining of 2 fluorescent labels for estimation of bone cell activity at baseline and after 11 weeks of healing. The animals were sacrificed after 12 weeks. Dissected blocks were processed for histologic, histomorphometric, and fluorescence microscopic analysis, ie, percentage of bone-to-implant contact (BIC) and percentage linear bone height (LBH) were measured. Student t and Mann Whitney U tests were used for statistical analysis (P < .05). Results: Healing was uneventful in all dogs. Augmentech injectable calcium Phosphate Cement showed good space maintenance and osteoconductive properties with no foreign body reaction. BIC was 34.42 (± 19.88) and 37.00 (± 21.33) (P = .375), while LBH was 84.23 (± 19.73) and 96.10 (± 6.66) (P = .125) for test and control sites, respectively. Conclusion: Within the limits of the present study, it was concluded that Augmentech injectable calcium Phosphate Cement may be a suitable material for the treatment of buccal dehiscence defects around dental implants. INT J ORAL MAXILLOFAC IMPLANTS 2008;23:1053‐1062.
-
injectable calcium Phosphate Cement for bone repair and implant fixation
Orthopedic Clinics of North America, 2005Co-Authors: John A. Jansen, Edwin Ooms, Nico Verdonschot, Joop WolkeAbstract:The studies as described are aimed at determining the efficacy of newly developed calcium Phosphate Cement when this material is used as a bone defect filler or gap filler around metal implants. An overview is provided about bone graft substitutes and methods of metal implant fixation.
-
rhbmp 2 release from injectable poly dl lactic co glycolic acid calcium Phosphate Cement composites
Journal of Bone and Joint Surgery American Volume, 2003Co-Authors: Quinten P Ruhe, Elizabeth L Hedberg, Nestor Torio Padron, John A. Jansen, Paul H M Spauwen, Antonios G MikosAbstract:Background: In bone tissue engineering, poly(DL-lactic-co-glycolic acid) (PLGA) microparticles are frequently used as a delivery vehicle for bioactive molecules. Calcium Phosphate Cement is an injectable, osteoconductive,and degradable bone Cement that sets in situ. The objective of this study was to create an injectable composite based on calcium Phosphate Cement embedded with PLGA microparticles for sustained delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2). Methods: 1 2 5 I-labeled rhBMP-2 was incorporated in PLGA microparticles. PLGA microparticle/calcium-Phosphate Cement composites were prepared in a ratio of 30:70 by weight. Material properties were evaluated by scanning electron microscopy, microcomputed tomography, and mechanical testing. Release kinetics of rhBMP-2 from PLGA/calcium-Phosphate Cement disks and PLGA microparticles alone were determined in vitro in two buffer solutions (pH 7.4 and pH 4.0) for up to twenty-eight days. Results: The entrapment yield of rhBMP-2 in PLGA microparticles was a mean (and standard deviation) of 79% ′ 8%. Analysis showed spherical PLGA microparticles (average size, 17.2 ′1.3 μm) distributed homogeneously throughout the nanoporous disks. The average compressive strength was significantly lower (p < 0.001) for PLGA and calcium-Phosphate Cement composite scaffolds than for calcium-Phosphate Cement scaffolds alone (6.4 ′ 0.6 MPa compared with 38.6 ′ 2.6 MPa, respectively). Average rhBMP-2 loading was 5.0 ′ 0.4 μg per 75-mm 3 disk. Release of rhBMP-2 was limited for all formulations. At pH 7.4, 3.1% ′ 0.1% of the rhBMP-2 was released from the PLGA/calcium-Phosphate Cement disks and 18.0% ′ 1.9% was released from the PLGA microparticles alone after twenty-eight days. At pH 4.0, PLGA/calcium-Phosphate Cement disks revealed more release of rhBMP-2 than did PLGA microparticles alone (14.5% ′ 6.3% compared with 5.4% ′ 0.7%) by day 28. Conclusions: These results indicate that preparation of a PLGA/calcium-Phosphate Cement composite for the delivery of rhBMP-2 is feasible and that the release of rhBMP-2 is dependent on the composite composition and nanostructure as well as the pH of the release medium. Clinical Relevance: An osteoconductive and osteoinductive rhBMP-2-loaded PLGA/calcium-Phosphate Cement composite may potentially result in an injectable bone-graft substitute for the regeneration of bone in ectopic or orthotopic sites.
-
in vivo bone response to porous calcium Phosphate Cement
Journal of Biomedical Materials Research Part A, 2003Co-Authors: R. P. Real, E M Ooms, Maria Valletregi, Johannes G. C. Wolke, John A. JansenAbstract:We conducted an in vivo experiment to evaluate the resorption rate of a calcium Phosphate Cement (CPC) with macropores larger than 100 microm, using the CPC called BioCement D (Merck Biomaterial, Darmstadt, Germany), which after setting only shows pores smaller than 1 microm. The gas bubble method used during the setting process created macroporosity. Preset nonporous and porous Cement implants were inserted into the trabecular bone of the tibial metaphysis of goats. The size of the preset implants was 6 mm and the diameter of the drill hole was 6.3 mm, leaving a gap of 0.3 mm between implant surface and drill wall. After 2 and 10 weeks, the animals were euthanized and Cement implants with surrounding bone were retrieved for histologic evaluation. Light microscopy at 2 weeks revealed that the nonporous implants were surrounded by connective tissue. On the Cement surface, we observed a monolayer of multinucleated cells. Ten weeks after implantation, the nonporous implants were still surrounded by connective tissue. However, a thin layer of bone now covered the implant surface. No sign of Cement resorption was observed. In contrast, the porous Cement evoked a completely different bone response. At 2 weeks, bone formation had already occurred inside the implant porosity. Bone formation even appeared to occur as a result of osteoinduction. Also, at their outer surface, the porous implants were completely surrounded by bone. At 2 weeks, about 31% of the initial Cement was resorbed. After 10 weeks, 81% of the initial Phosphate Cement was resorbed and new bone was deposited. On the basis of these observations, we conclude that the creation of macropores can significantly improve the resorption rate of CPC. This increased degradation is associated with almost complete bone replaCement.
Changsheng Liu - One of the best experts on this subject based on the ideXlab platform.
-
premixed injectable calcium Phosphate Cement with excellent suspension stability
Journal of Materials Science: Materials in Medicine, 2013Co-Authors: Fangping Chen, Yuhao Mao, Changsheng LiuAbstract:Premixed injectable calcium Phosphate Cement (p-ICPC) pastes have advantages over aqueous injectable calcium Phosphate Cement (a-ICPC) because p-ICPC remain stable during storage and harden only after plaCement into the defect. This paper focused on the suspension stability of p-ICPC paste by using fumed silica as a stabilizing agent and propylene glycol (PEG) as a continuous phase. Multiple light scanning techniques were first applied to evaluate the suspension stability. The results indicated that fumed silica effectively enhanced the suspension stability of p-ICPC pastes. The stabilizing effect of fumed silica results from the network structure formed in PEG because of its thixotropy. The p-ICPC could be eventually hydrated to form hydroxyapatite under aqueous circumstances by the unique replaCement between water and PEG. p-ICPC (1) not only possesses proper thixotropy and compressive strength but has good injectability as well. p-ICPC (1) was cytocompatible and had no adverse effect on the attachment and proliferation of MG-63 cells in vitro. These observations may have applicability to the development of other nonaqueous injectable biomaterials for non-immediate filling and long-term storage.
-
maxillary sinus floor elevation using a tissue engineered bone with calcium magnesium Phosphate Cement and bone marrow stromal cells in rabbits
Tissue Engineering Part A, 2012Co-Authors: Deliang Zeng, Jie Wei, Changsheng Liu, Lunguo Xia, Wenjie Zhang, Hui Huang, Bin Wei, Qingfeng Huang, Xinquan JiangAbstract:The objective of this study was to assess the effects of maxillary sinus floor elevation with a tissue-engineered bone constructed with bone marrow stromal cells (bMSCs) and calcium-magnesium Phosphate Cement (CMPC) material. The calcium (Ca), magnesium (Mg), and phosphorus (P) ions released from calcium Phosphate Cement (CPC), magnesium Phosphate Cement (MPC), and CMPC were detected by inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the proliferation and osteogenic differentiation of bMSCs seeded on CPC, MPC, and CMPC or cultured in CPC, MPC, and CMPC extracts were measured by MTT analysis, alkaline phosphatase (ALP) activity assay, alizarin red mineralization assay, and real-time PCR analysis of the osteogenic genes ALP and osteocalcin (OCN). Finally, bMSCs were combined with CPC, MPC, and CMPC and used for maxillary sinus floor elevation in rabbits, while CPC, MPC, or CMPC without cells served as control groups. The new bone formation in each group was detected by histological fi...
-
self setting bioactive calcium magnesium Phosphate Cement with high strength and degradability for bone regeneration
Acta Biomaterialia, 2008Co-Authors: Jie Wei, Han Guo, Fangping Chen, Hua Hong, Changsheng LiuAbstract:Calcium Phosphate Cement (CPC) has been successfully used in clinics as bone repair biomaterial for many years. However, poor mechanical properties and a low biodegradation rate limit any further applications. Magnesium Phosphate Cement (MPC) is characterized by fast setting, high initial strength and relatively rapid degradation in vivo. In this study, MPC was combined with CPC to develop novel calcium-magnesium Phosphate Cement (CMPC). The setting time, compressive strength, phase composition of hardened Cement, degradation in vitro, cells responses in vitro by MG-63 cell culture and tissue responses in vivo by implantation of CMPC in bone defect of rabbits were investigated. The results show that CMPC has a shorter setting time and markedly better mechanical properties than either CPC or MPC. Moreover, CMPC showed significantly improved degradability compared to CPC in simulated body fluid. Cell culture results indicate that CMPC is biocompatible and could support cell attachment and proliferation. To investigate the in vivo biocompatibility and osteogenesis, the CMPC samples were implanted into bone defects in rabbits. Histological evaluation showed that the introduction of MPC into CPC enhanced the efficiency of new bone formation. CMPC also exhibited good biocompatibility, biodegradability and osteoconductivity with host bone in vivo. The results obtained suggest that CMPC, having met the basic requirements of bone tissue engineering, might have a significant clinical advantage over CPC, and may have the potential to be applied in orthopedic, reconstructive and maxillofacial surgery.
Sander C G Leeuwenburgh - One of the best experts on this subject based on the ideXlab platform.
-
stabilizing dental implants with a fiber reinforced calcium Phosphate Cement an in vitro and in vivo study
Acta Biomaterialia, 2020Co-Authors: Sonia De Lacerda Schickert, John A. Jansen, Ewald M Bronkhorst, Jeroen J J P Van Den Beucken, Sander C G LeeuwenburghAbstract:Abstract Stabilization of dental implants by means of biomaterials such as bioceramic granules and Cements is currently compromised by the poor mechanical properties of these bioceramics. Recently, our group developed a calcium Phosphate Cement reinforced with poly(vinyl alcohol) fibers with improved flexural strength and toughness. Herein we evaluated the capacity of these fiber-reinforced calcium Phosphate Cements to stabilize dental implants in vitro and in vivo using a range of mechanical and biological test methods. In vitro, filling of circumferential crestal peri‑implant bone defects with synthetic bone analogues with fiber-reinforced calcium Phosphate Cement demonstrated superior implant stability as compared to fiber-free calcium Phosphate Cement over a 12-week period. Similarly, filling of circumferential crestal peri‑implant bone defects with fiber-reinforced calcium Phosphate Cement effectively stabilized dental implants installed in a rabbit femoral condyle defect as assessed via both Implant Stability Quotient (ISQ) and torque-out measurements. Moreover, histological and histomorphometric evaluation demonstrated the osteocompatibility of fiber-reinforced calcium Phosphate Cement, as evidenced by absence of soft tissue ingrowth, direct contact between the bone and Cement, and gradual degradation of the biomaterial and replaCement by newly-formed bone. These data demonstrate that fiber-reinforced calcium Phosphate Cement stabilize dental implants during osseointegration. Statement of significance Dental implants can be placed immediately after a tooth is removed. However, in some cases the implant might not have enough bone surrounding it and becomes loose. To solve this, bioceramics have been used to fill the implant-bone gap. However, these materials have poor mechanical properties and are often not capable to stabilize the implant. Recently, our research group developed a new bone Cement that is reinforced with fibers and has, therefore, enhanced mechanical properties. In this study, we have proven that by molding this Cement into the implant-bone gap, we stabilize the implant and allow for a direct connection between the implant and the surrounding bone. Using this innovative Cement is therefore a safe and efficient way of stabilizing dental implants.
Bing Chen - One of the best experts on this subject based on the ideXlab platform.
-
characterization of magnesium Phosphate Cement incorporating waste glass powder as mineral admixture
Journal of Materials in Civil Engineering, 2021Co-Authors: Yuantao Liu, Bing Chen, Zhaohui QinAbstract:AbstractThis article utilized waste glass in the form of glass powder (GP) and researched its effects on the properties of magnesium Phosphate Cement (MPC), which were investigated via working prop...
-
experimental research on properties and microstructures of magnesium iron Phosphate Cement
Construction and Building Materials, 2020Co-Authors: Yuantao Liu, Zhaohui Qin, Bing Chen, Dong Pen, Aminul M HaqueAbstract:Abstract A novel magnesium-iron Phosphate Cement was prepared based on magnesium Phosphate Cement (MPC), by incorporating various proportions of Fe2O3 powder as MgO powder replaCement. The research mainly concentrated on the improvement of properties and optimization of microstructure, which were measured in terms of the setting time, fluidity, compressive strength and flexural strength, and analyzed by X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), scanning electron microscopy (SEM) and thermogravimetric (TGA-DTG). Fe2O3 powder decreased that fluidity of the fresh paste and prolonged the setting time to a value of 16 min. The mechanical property was increased with the addition of Fe2O3 powder, and the group containing 20% Fe2O3 powder yielded the highest 28-day compressive strength of 58.7 MPa. Fe2O3 enhanced the crystallization of struvite, participated in the reaction and produced some new hydrates. It also had good pore-filling effect and compacted the microstructure. The analyses on the iron-Phosphate system illustrated that the reaction between Fe2O3 and ADP was promoted by high curing temperature, and confirmed that Fe2O3 could be activated in the MPC system.
-
in vitro and in vivo research advanCements on the magnesium Phosphate Cement biomaterials a review
Materialia, 2020Co-Authors: Aminul M Haque, Bing ChenAbstract:Abstract The key aim of this review study is to expose the in vitro and in vivo research progresses on the Magnesium Phosphate Cement (MPC) bioceramics in the orthopedic and dental zones through congregating the vital outcomes of the studies performed by the global scholars. More importantly, the paper mainly concentrates on the comparison of physico-mechanical properties between the MPC materials and human bone, bone healing and bioresorption mechanisms of MPC graftings, development of in vitro properties such as injectability to bone cracks filling, root canal filling, dentin bond strength and antibacterial performance, and success in the in vivo studies of bone defects recover in rapid time of MPC implantation. Exploration results confirm that MPC transplants are adjustable to foreign body, fully degrade over time maintaining structural stiffness to support the movement of crack zones and play vital role to bone metabolism for healing. These characteristics will stimulate to be a potential alternative to the conventional ceramics like calcium Phosphate Cement (CPC) for special clinical applications. The study also suggests some future directions that are still needed to be investigated for rigorous improvement of MPC substitutes, which are demanding in the orthopedic zones.
-
properties of pervious concrete made from steel slag and magnesium Phosphate Cement
Construction and Building Materials, 2019Co-Authors: Lei Lang, Haijuan Duan, Bing ChenAbstract:Abstract The new pervious concrete (PC) were prepared using magnesium Phosphate Cement (MPC) as binding and waste steel slag as coarse aggregate. A series of laboratory experiments were carried out to study the influence of aggregate size and molding method on the compressive strength, flexural strength, porosity and water permeability coefficient of magnesium Phosphate Cement steel slag pervious concrete (MSPC). Experimental results showed that the influence of aggregate size on compressive strength is different when different molding methods were adopted. Through comparative analysis, the MSPC with medium particle size formed by vibration molding had the highest compressive strength, and the maximum can reach 41.5 MPa. Based on the excellent bonding strength of MPC, the MSPC has better flexural strength than traditional PC, and the maximum 28-day flexural strength can reach 8.0 MPa. The porosity increases with the increase of aggregate size, and which is in the range of 23.8–26.5% for all the MSPC mixtures. Similarly, the water permeability coefficient of MSPC increases as the increase of aggregate size, and with the range from 5.85 to 7.10 mm/s. The 28-day bend-press ratio of MSPC is close to 1/5. Unlike the traditional PC, the mechanical strength of MSPC increased first and then decreased with the porosity, while regardless of aggregate size and molding method, the water permeability coefficient increased linearly with the porosity. The test results indicate that the MSPC made of steel slag aggregates and MPC is a very promising eco-friendly PC.
-
performance of magnesium Phosphate Cement at elevated temperatures
Construction and Building Materials, 2015Co-Authors: Tongfei Shi, Bing ChenAbstract:Abstract This research studied effect of elevated temperature on properties of magnesium Phosphate Cement (MPC). Properties, including strength, colour, mass loss, and microstructure, of MPC specimens before and after exposure different high temperature were measured or observed in this paper. Seven sample mixtures contained varying amounts of fly ash and sand are considered in the experimental program. The mechanical properties of MPC were measured by heating 40 × 40 × 160 mm sample to 130, 500 and 1000 °C at a rate of 10 °C/min. The obtained results demonstrate that strength of MPC decreased significantly when the temperature passed 130 °C. After 130 °C, the amplitude of strength decreased of MPC became less with the increasing of temperature. The results of Differential thermal analysis (DTA) and thermo-gravimetric analysis (TG) indicate that the crystal water in MKP·6H2O were lost at the temperature of 125 °C. The loss of crystal water in MKP·6H2O was the main reason of strength decreasing and mass loss of MPC after exposure to high temperature. The results also show that the presence of fly ash and sand decrease residual strength of MPC.