Magnesium Phosphate Research Articles

Surface functionalization of calcium magnesium phosphate cements with alginate sodium for enhanced bone regeneration via TRPM7/PI3K/Akt signaling pathway

Although calcium‑magnesium phosphate cements (CMPCs) have been widely applied to treating critical-size bone defects, their repair efficiency is unsatisfactory owing to their weak surface bioactivity and uncontrolled ion release. In this study, we lyophilized alginate sodium (AS) as a coating onto HAp/K-struvite (H@KSv) to develop AS/HAp/K-struvite (AH@KSv), which promotes bone regeneration. The compressive strength and hydrophilicity of AH@KSv significantly improved, leading to enhanced cell adhesion in vitro. Importantly, the SA coating enables continuous ions release of Mg2+ and Ca2+, finally leading to enhanced osteogenesis in vitro/vivo and different patterns of new bone ingrowth in vivo. Furthermore, these composites increased the expression levels of biomarkers of the TRPM7/PI3K/Akt signaling pathway via an equilibrium effect of Mg2+ to Ca2+. In conclusion, our study provides novel insights into the mechanisms of Mg-based biomaterials for bone regeneration.

A preliminary study on preparation and properties of magnesia based clinker with zeolite and magnesite

Dead burnt magnesia is the main raw material of magnesium phosphate cement, which is widely used in road repair works. However, due to the high energy consumption and high cost in the production and preparation process of dead burnt magnesia, its application is limited to a certain extent. In this work, a magnesia based clinker containing a considerable number of magnesium oxide and magnesium silicates phase was prepared by co-firing of zeolite powder and magnesite at low temperature (1200–1300 ℃). The results show that high temperature than 1200℃ results in less free MgO. Intermediate phases 2CaO·MgO·2SiO2 formed in clinker at 1250℃ and 1300℃. The workability of the pastes made from calcined cement clinker was proved to be better than that of traditional magnesium potassium phosphate cement (MKPC). The compressive strength can reach 30 MPa after curing for 7 days. Compared with the traditional MKPC, the hydration heat of the new magnesia based cement is greatly reduced. Lower calcination temperature on the cement clinker resulted in fewer cracks and pores on the surface of magnesia based cement and denser structure of the hydration products.

Effects of incorporation of nanotitania in magnesium phosphate cement for the protection of carbon steel in harsh environments

Effects of incorporation of nanotitania in magnesium phosphate cement for the protection of carbon steel in harsh environments

Analysis of the Strength of Different Minerals-Modified MPC Based on Mathematical Models

The study discussed the effects of different mineral incorporations and the curing time on the strength of modified magnesium phosphate cement (MPC) mortars through mechanical tests, mathematical model analysis and microstructure characterization. Fly ash (FA), silica fume (SF), and metakaolin (MK), which exhibit excellent durability and bonding properties, were used to modify the MPC. A quantitative relationship was established between the strength of modified MPC mortars and the mineral incorporation and curing time. First, the strength of each mineral-modified MPC mortar cured in air with different mineral incorporations and curing durations was evaluated. The strengths of MPC mortars containing 10% fly ash, 15% silica fume, and 10% metakaolin—which perform best in their incorporations—were compared to analyze the function of the three minerals. To establish the relationship between strength and mineral incorporation and curing time, three mathematical models, linear model, general nonlinear model, and data distribution shape nonlinear model (DDSNM), are commonly used for material property analysis based on statistics. DDSNM best describes the trend of strength change among the three models and the error is small for three minerals. Based on DDSNM, the influence of various minerals on the strength of MPC mortar was quantitatively evaluated by calculating the variable partial derivatives, and verified by scanning electron microscopy and X-ray diffraction. MK performs the best in improving the flexural strength performance of MPC, while SF performs the best in the compressive strength. FA-MPC has low sensitivity to dosage fluctuations and is easy to prepare.

Optimization of printing precision and mechanical property for powder-based 3D printed magnesium phosphate cement using fly ash

Fly ash (FA) is employed to optimize the hydration process of powder-based (inkjet) 3D printed magnesium phosphate cement (MPC), aiming to enhance the printing precision and mechanical properties of powder-based 3D printed structures. This paper systematically evaluates the effects of FA on the printability, printing precision, and mechanical properties of printed MPC. In addition, SEM, XRD, and X-CT are used to analyze the hydration morphology, products, and pore structure of printed MPC, respectively. The test results reveal that the proper addition of FA can effectively optimize the penetration process between the binder and powder bed to improve the printing precision of powder-based 3D printed MPC with the minimum printing size error controlled within 1%, which also achieves the maximum compressive strength of 10.1 MPa at 28d under room environment curing. Due to the pozzolanic and micro-aggregate effects, FA can significantly improve the hydration degree and optimize the pore structure of printed MPC with the total porosity decreased by 24%. The high precision of the printed complicated electromagnetic metasurface models further demonstrates the applicability of powder-based 3D printing with FA-optimized MPC.

2D magnesium phosphate resorbable coating to enhance cell adhesion on titanium surfaces

Titanium and its alloys are essential metals for orthopedic implant manufacturing due to their exceptional mechanical properties and biocompatibility, used extensively for treating various orthopedic conditions. However, Titanium (Ti) implants have a disadvantage due to lack of bioactivity, potentially affecting osseointegration and osteoconductive capabilities, and may take several months to integrate with bone tissue. In this work, we prepared a layer of 2D magnesium phosphate (MgPi) coating on the surface of titanium surfaces via the spin-coating technique. Various techniques were used to study the phase composition of the coatings, including FTIR, Raman spectroscopy, NMR, and XRD analysis. Morphology and chemical analysis were performed using Atomic force microscopy and SEM/EDX. Nano-scratch test and water contact angle measurements were used to measure adhesion strength and wettability. In addition, in vitro cell assays were used to assess cell adhesion and viability to determine how the MC3T3-E1 osteoblast-like cells reacted to the different treated Ti substrates. AFM results showed that the surface roughness became lower after coatings. MgPi-coated samples showed higher hydrophilicity, protein adsorption, and cell viability than uncoated samples. The nano-scratch test showed that the MgPi coating showed better adherence to chemically and thermally treated samples compared to untreated samples. The deposited MgPi coating has good adhesion to the Ti-substrates. Most significantly, compared to uncoated control (Ti) (p < 0.005) and chemically treated coated samples CT-MgPi (p < 0.005), MC3T3-E1 cell proliferation was significantly increased on thermochemical coated surfaces. These findings point to resorbable two-dimensional MgPi coatings as a potential candidate for promoting Ti implant osseointegration.

Properties and reaction mechanism of magnesium phosphate cement modified by calcium lactate

The properties of magnesium phosphate cement (MPC) are studied by measurements of setting time, flowability, compressive strength and by multiple technique analyses of pH values, calorimetry, XRD, TG, MIP and SEM taking calcium lactate (CL) content as variables. Results show that CL can significantly prolong the setting time and promote the synergetic development of compressive strength of MPC, but the addition of CL leads to a decrease in flowability of MPC. Comprehensive consideration on these properties, the optimal dosage of CL is 5%. In this case, the setting time, flowability and 1 day & 28 days compressive strength of MPC are 84 minutes, 185 mm, 40.8 MPa & 54.2 MPa, respectively. Multiple technique analyses show that the addition of CL can decrease the liquid phase pH value and hydration rate of MPC, resulting in the extension of setting time. A low content of CL (3%) can improve the reaction degree and optimize the matrix pore structure of MPC, and thus promoting the strength development (50.90 MPa increased to 65.93 MPa). However, an excessive addition of CL (7%) will lead to the decrease in reaction products and the increase in matrix porosity of MPC, resulting in a decrease in compressive strength (43.30 MPa reduced to 37.36 MPa).

Trade-Off Strategy for Usage of Phosphorus Fertilizer in Calcareous Soil-Grown Winter Wheat: Yield, Phosphorus Use Efficiency, and Zinc Nutrition Response

Although phosphorus (P) fertilizer application is widely used to improve production, irrational P application has a negative impact on the zinc (Zn) nutrition of cereal crops. Previous researchers observed and confirmed that P application decreases grain Zn concentrations and bioavailability in cereal crops. However, it remains unclear whether different P fertilizer types can alleviate the antagonism of P and Zn in the soil and grain and, thus, enhance the Zn nutritional level of cereal crops while maintaining production. Thus, a completely randomized pot experiment was conducted on winter wheat grown in two calcareous soils (lime concretion black soil and fluvo-aquic soil). Five P fertilizer types (single superphosphate, diammonium phosphate, fused calcium–magnesium phosphate, triple superphosphate, and ammonium polyphosphate, abbreviated, respectively, as SSP, DAP, FMP, TSP, and APP) were applied to each soil compared to no P fertilizer (CK). Plant and topsoil samples were collected during the flowering and maturity stages of winter wheat, and biomass, Zn concentrations in each organ, and grain phytic acid concentrations were analyzed. Grain yield was not affected by the application of different P fertilizer types to lime concretion black soil, while it was significantly increased by the application of TSP and APP to fluvo-aquic soil. The application of DAP and APP effectively promoted soil available Zn concentrations in both calcareous soils. In lime concretion black soil, the application of FMP significantly increased Zn remobilization to grains, while the application of DAP increased post-anthesis Zn uptake, thereby increasing grain Zn concentrations and its bioavailability. In fluvo-aquic soil, post-anthesis Zn remobilization and uptake were significantly increased by the application of TSP and APP, finally achieving higher grain Zn concentrations and Zn harvest index and effectively promoting grain Zn bioavailability. In conclusion, the rational application of DAP to wheat grown in lime concretion black soil and of TSP or APP to fluvo-aquic soil can achieve superior grain Zn nutrition quality while concurrently retaining high production and high P use efficiency, reducing micronutrient deficiency and further contributing to green agricultural development and human health.

Role of Fly Ash in the Repair Interface between Magnesium Phosphate Cement and Cement Concrete

This paper examines a rapid repair material for cement concrete pavement based on magnesium phosphate cement (MPC) blended with fly ash (FA). Three kinds of stress forms for rapid repair of Portland cement concrete pavement (PCCP) were evaluated and the role of FA in the repair interface was studied. The optimal mixture ratio of FA-MPC mortar was determined, and the compressive and flexural strength tested. The composite specimens were then designed to test the interfacial bonding, tensile, and plain shear strength. Finally, the multi-scale mechanism of FA in the interface was analyzed by a pull-off adhesion test, nanoindentation test, scanning electron microscope (SEM)/energy dispersive spectrometer (EDS), Raman spectrum, and molecular dynamics simulation. The optimal content of FA in MPC mortar was 20%. The laminated beam structure had the maximum strength, and the interface load bearing capacity was the lowest. For further multi-scale analysis, the results of the pull-off adhesion test showed the adhesion strength of interface was increased by the curing age and loading rate. Adhesion capacity of basalt aggregate and FA-MPC was stronger than that of Portland cement mortar and FA-MPC. The elastic modulus of MPC-aggregate interface was more than that of MPC-OPC mortar. SEM/EDS and Raman spectrum results showed that the MPC blended with FA had cracks and defects at the interface formed with cement mortar. Less FA formed near the interface. The good adhesion ability of FA and basalt aggregate was verified by molecular dynamics simulation. By contrast, poor adhesion strength with cement mortar was confirmed.

Development of guar gum reinforced calcium magnesium phosphate-based bone biocement.

This study aims at developing a calcium magnesium phosphate-based bone biocement that combines a natural polymer and regenerative properties of bone bonding materials. The formulation of this biocement consists of oxidized guar gum, polydopamine, and calcium magnesium phosphate. The oxidized guar gum is easily soluble in water and has a slightly basic pH, unlike unmodified guar gum, thus allowing a homogenous paste to form in the alkaline environment of calcium magnesium phosphate. Three different oxidized degrees of guar gum were made, and the impact on the biocement properties was studied. The modified guar gum-reinforced biocement (OGG C2) displayed higher mechanical strength and lower degradation rates than OGG B1 and OGG A0. Furthermore, samples with polydopamine exhibited better results, thus, improving the already reinforced biocement. Morphological studies of the biocement displayed a highly porous structure with porosity varying among biocement containing different oxidized guar gum and polydopamine levels.

Hydration properties of magnesium phosphate cement paste mixed with metakaolin and silica fume

AbstractMagnesium phosphate cement (MPC) exhibits a faster setting time and higher early strength, making it suitable for crack repair. However, its application in civil engineering is hindered by its fast initial hydration rate and poor water resistance. To address these limitations, metakaolin (MK) and silica fume (SF) were utilized to enhance the properties of MPC. The effects of MK and SF on the setting time, compressive strength, water resistance, hydration process, and microstructure of MPC were investigated. The results demonstrate that both MK and SF significantly prolong the setting time of MPC and improve its water resistance. The main hydration products of MPC, after incorporating MK and SF, are k‐struvite (MgKPO4·6H2O) and unreacted MgO. The presence of MgSiO3 and AlPO4 also contributes to the enhancement of compressive strength and water resistance. The incorporation of MK and SF actively participates in the hydration reaction of the MPC system. Furthermore, MgSiO3 and AlPO4 intertwine with MKP, resulting in a denser internal structure of the cured MPC, thereby improving its water resistance.

Bond strength and interface characteristics between magnesium phosphate cement mortar and ordinary Portland cement concrete in a frigid environment

ABSTRACT The rapid repair of airport runways and concrete pavements using magnesium phosphate cement mortar (MPCM) in frigid environments requires the MPCM to have high bond strength with ordinary Portland cement (OPC). In this study, the effects of the pouring temperature of MPCM, surface roughness, water content, and strength grade of concrete on the interfacial bond strength and characteristics between MPCM and OPC were investigated in a frigid environment (−20°C ± 2°C). The results indicated that the 3-h compressive strength of MPCM reached 30 MPa, whereas the 3-h flexural bond strength between MPCM and OPC (BS MPCM-OPC) exceeded 2.5 MPa when the pouring temperature for the MPCM mixture is 0-5°C in a frigid environment. The moisture content of concrete before freezing had a more significant impact on BS MPCM-OPC than the influence of concrete roughness in a frigid environment; however, the influence of the concrete strength grade can be disregarded. The hydration heat of MPCM can quickly release with an increase in the pouring temperature, which accelerates phosphate dissolution and promotes the generation of struvite and the development of the BS MPCM-OPC. Furthermore, the interface bonding between MPCM and OPC involves physical bonding, mechanical anchoring, and weak chemical bonding in a frigid environment.

Phase and microstructure evolution of the hydration products of magnesium phosphate cements under sulfuric acid environments

Magnesium phosphate cement is a good canditate of repairing material served under harsh environments and its acid resistivity has drawn a lot of interest, but rare detailed research on the evolution of its physiochemical features has been reported. In this work, the impacts of sulfuric acid solution (pH = 2 – 7) on the hydration products of magnesium potassium phosphate cement and magnesium ammonium phosphate cement. Results showed that the main hydration products, struvite/struvite–K, experienced partial corrosion in the absence of the sulfuric acid solution replacement. The phase transition of struvite–K is clearly visible, leading to the formation of the new crystalline hydration product Mg3(PO4)2•22 H2O. The initial blossoms cluster microstructure transformed into a diffused dispersion that resembled a plate. When the solution was replaced, struvite/struvite–K underwent significant corrosion and even complete decomposition in more acidic (pH = 2, 3) solutions.

Toughness and strength of PVA-fibre reinforced magnesium phosphate cement (FRMPC) within 24 h

Cement with high toughness and early strength are widely utilized in the field of rapid repair. This study is focused on the development of PVA fibre reinforced magnesium phosphate cement (FRMPC) that possesses these properties. The compressive, flexural, and tensile strengths of the FRMPC were measured at various ages, including 1, 2, 3, 4, 5, 6 and 24 h. The relationships of the element contents, hydration products, hydration process, and the microscopic morphology with the mechanical properties were analyzed. Importantly, the mechanical formation process of the 6 h was analyzed in detail. Results show that the tensile strain of the FRMPC exceeded 3% at all ages, and the flexural strength was greater than 10 MPa at all ages. The compressive strength reached 15.53 and 25.63 and 32.48 MPa after 1 h, 6 h and 24 h, respectively. The ultimate tensile strength, flexural strength and compressive strength of 6 h reached 98%, 90% and 78% of the final strength of 24 h.The incorporation of fly ash and quartz sand mitigates the exothermic rate of hydration and optimizes the filler structure. Furthermore, the addition of fly ash engenders an amorphous phase gelling material and MgSiO3, characterized by effective filler properties.This results in an enhanced integration of PVA fibres with the cement matrix, thereby exhibiting improved toughness.The main hydration product was MgKPO4 × 6 H2O, and its formation rate and amount affected the mechanical properties. The nature of the hydration products and the density of the specimen structure were determined to be key factors in the progression of uniaxial tensile properties. FRMPC's strength, toughness and shrinkage are in a relatively good state, and the potential for its early-stage mechanical properties still can be improved.

Synthesis and characterization of complex phosphates of alkaline elements, magnesium and zirconium as potential ceramics for nuclear waste immobilization

Phases of variable composition A2−хА'хMg0.5Zr1.5(PO4)3 (АA' – KNa, KRb, KCs, 0 ≤ x ≤ 2) with langbeinite and kosnarite structures can serve as matrices immobilizing radioactive waste. They were synthesized by sol-gel method followed by heat treatment and investigated by X-ray diffraction at different temperatures, IR spectroscopy, scanning electron microscopy and electron probe microanalysis. A Rietveld refinement of the KCsMg0.5Zr1.5(PO4)3 structure showed that the framework is formed by octahedra (Mg/Zr)O6 and tetrahedra PO4 connected by vertices; potassium and cesium cations are located in cavities. When the temperature changes, phosphates with the langbeinite structure expand uniformly in all directions: αа = αb = αc = (4.2−6.6) ∙ 10−6 °C−1, without undergoing polymorphic transitions. Phosphate Na2Mg0.5Zr1.5(PO4)3, which crystallizes in the kosnarite structure type, expands anisotropically: αа = −2.6·10−6, αс = 8.2·10−6, αav = 1.0·10−6 °C−1. The chemical durability test shows that the leaching rate of Cs ions from the solid solution with langbeinite structure is of the order of 10−5 g cm−2 d−1.

Referentne vrijednosti za odabrane hematološke i biokemijske parametre u pelagonijske pramenka ovce

The Ovcepolian type of Pramenka sheep is most prevalent in Pelagonia region. It is considered a valuable source of genetic diversity, characterised with a number of beneficial traits. Haematology and biochemistry measurements is important for health assessment of animals. The aim of this study was to determine the reference ranges for selected haematology and biochemistry parameters in the Pelagonian Pramenka sheep breed. The study was carried out on 55 clinically healthy, non-pregnant sheep, 1 to 3 years old, during spring season, from three different locations in the Pelagonia region, North Macedonia. Blood samples were collected from the jugular vein into vacuum tubes with an anticoagulant for haematological analysis and vacuum tubes free of anticoagulant for biochemical analysis. Reference values may be more adequate as it is later, for biochemistry parameters. Reference values for hematology parameters were: leukocytes, lymphocytes, midsize cells, cells correlating to monocytes, eosinophils, basophils, blasts and other precursor white cells, granulocytes, haemoglobin, haematocrit, erythrocytes, erythrocyte indices (average volume per litre, average haemoglobin in erythrocytes, average haemoglobin concentration per litre, and platelets). Reference values for biochemistry parameters were: total proteins, albumins, total bilirubin, total cholesterol, creatinine, glucose, HDL-cholesterol LDL-cholesterol, triglycerides, urea, aspartate aminotransferase, alanine amino transferase, alkaline phosphatase, glutamyl transferase, lactate dehydrogenase, and the concentrations of calcium, magnesium and inorganic phosphate. Most obtained values were comparable to other strains of Pramenka sheep. There was a clear deviation of certain reference values compared to the literature. Further analysis should be conducted to determine the reference values in rams and lambs.

Safe Utilization Effect of Passivator on Mild to Moderate Cadmium Contaminated Farmland

In order to study the safe utilization of acid cadmium （Cd） contaminated soil， light and moderate Cd-contaminated farmland in Shangluo， Shaanxi Province was taken as the research object， and lime， biochar， and calcium magnesium phosphate fertilizer were applied. Through the wheat-maize rotation experiment， the safe utilization effect of different amounts of passivator on Cd-contaminated soil was explored， and the best ratio of passivator was selected. The results showed that： ① the soil quality could be improved to varying degrees by applying the passivator. ② After the application of amendments， the grain yield of wheat and maize increased to different degrees. ③ The lime 2 340 kg·hm-2 （C3） treatment had the best effect， which increased the soil pH of wheat and corn by 1.453 and 1.717 units， respectively， and reduced the available Cd content by 34.38% and 30.20%， respectively. ④ The application of biochar 1 800 kg·hm-2 （B2） treatment had the best effect on reducing the Cd contents in wheat roots， straws， and grains， which were significantly reduced by 53.60%， 38.86%， and 52.96%， respectively， compared with that in CK. The Cd content in wheat grains was reduced to 0.09 mg·kg-1， which was lower than the limit value of wheat Cd （0.1 mg·kg-1） specified in the "National food safety standard food pollutant limit" （GB 2762-2017）. The application of the biochar 1 260 kg·hm-2 （B1） treatment had the best comprehensive effect on reducing the Cd contents of maize roots， straws， and grains， which were significantly reduced by 43.74%， 53.20%， and 94.57%， respectively， compared with that in CK. The Cd content of maize grains was reduced to 0.001 9 mg·kg-1， which was far lower than the limit value of maize Cd （0.1 mg·kg-1） specified in the "National food safety standard food pollutant limit" （GB 2762-2017）. Therefore， under the conditions of the field experiment， considering the influence of various indexes， biochar had the best effect on farmland soil in the wheat-maize rotation area with mild to moderate Cd pollution.

Bonding properties and mechanism of magnesium phosphate cement mortar-normal concrete interface

Magnesium phosphate cement (MPC) has mostly been employed as a repairing and reinforcing material for normal concrete (NC) structures. This research investigates the bonding properties and mechanisms of the MPC material-NC interface. To improve the repair effect of MPC materials, with the help of pull-off test and bi-surface shear test, modified MPC (SMMPC) mortar and polymer repair mortar (PRM) were used as comparative materials to analyze the effects of the type of repair material, the age of curing, and the method of interfacial treatment on the mechanical properties of the bonded interface. The microstructure of the bonded interface was investigated by scanning electron microscopy (SEM) technique and mercury in pressure (MIP) method. The results showed that SMMPC mortar had greater bonding performance than PRM, and the microstructure at the interface between the former and the NC substrate was denser. The shearing resistance of the bonded interface was greatly increased by chipping, reaching a maximum value of 53.2 kN. Compared with other brittle interfaces, the planting rebar interface showed good ductility during loading, and the failure slip of the relevant specimens was able to reach 2.51 mm, which was 20.7%–1041 % higher than that of the other specimens. Additionally, the method was put forward to calculate the bonding strength at the SMMPC mortar-NC interface.

Adsorption effect and mechanism of Cd(II) by different phosphorus-enriched biochars.

The resource utilization of agricultural and forestry waste, especially the high-value transformation of low-grade phosphate rock and derivatives, is an important way to achieve sustainable development. This study focuses on the impregnation and co-pyrolysis of rice straw (RS) with fused calcium magnesium phosphate (FMP), FMP modified with citric acid (CA-FMP), and calcium dihydrogen phosphate (MCP) to produce three phosphorous-enriched biochars (PBC). The Cd(II) removal efficiency of biochars before and after phosphorus modification was investigated, along with the adsorption mechanism and contribution of biochars modified with different phosphorus sources to Cd(II) adsorption. The result indicated that CA-FMP and MCP could be more uniformly loaded onto biochar, effectively increasing the specific surface area (SSA) and total pore volume. The adsorption of Cd(II) onto PBC followed a mono-layer chemisorption process accompanied by intraparticle diffusion. The adsorption of Cd(II) by PBC involved ion exchange, mineral precipitation, complexation with oxygen-containing functional groups (OFGs), cation-π interaction, electrostatic interaction, and physical adsorption. Ion exchange was identified as the primary adsorption mechanism for Cd(II) by BC and FBC (51.53% and 53.15% respectively), while mineral precipitation played a major role in the adsorption of Cd(II) by CBC and MBC (51.10% and 47.98% respectively). Moreover, CBC and MBC significantly enhanced the adsorption capacity of Cd(II), with maximum adsorption amounts of 128.1 and 111.5mgg-1 respectively.

Repair interface crack resistance mechanism: A case of magnesium phosphate cement overlay repair cement concrete pavement surface

Cement concrete pavements are continuously impacted by environment and vehicle loads, resulting in corner cracking, pockmarked surface and other distresses. It emerges a hot topic: reinforcement and repair. In recent years, magnesium phosphate cement (MPC) has been widely praised as a rapid repair material on cement concrete pavement. In this study, the crack resistance of a composite structure with MPC mortar overlay upon Portland cement concrete was investigated. First of all, the crack mouth opening displacement (CMOD) and double-K fracture parameters for different ratios of the precast notched crack length to height of composite specimen were obtained in the prenotched double-layered three-point bending beam (DLTPB) tests. The results showed that the peak force decreased with the decreasing ligament length. An exponential relationship between the fracture parameters to different ratios of the precast notched crack length to the height was observed. For the non-linear elastic fracture mechanics (non-LEFM) evaluation, MPC mortar overlay was beneficial for the flexural tensile performance and crack resistance of the composite structure. Results showed the agreement between experimental and theoretical CMODs. The crack initiation and propagation in DLTPB test was effectively determined by digital image correlation (DIC) method. It was found that MPC mortar overlay extended the fracture process zone (FPZ) as the crack propagated at the repair interface. The non-LEFM behaviors of composite MPC-concrete specimens were evaluated and capable of obviously similar with traditional cement-based materials. The elastic modulus measured by nano-indentation and the microscopic mechanism analyzed by SEM showed that the complex contact situation did not weaken the interface performance. However, the unique performance advantages of composite structure relied on not only the good performance of the MPC mortar overlay but also the strong bonding at repair interface. The results showed that the excellent interfacial mechanical properties assist to improve the crack resistance and prevent the cracks between concrete and MPC mortar from rapid propagation. It reflected that the MPC mortar overlay can hinder the crack propagation from the cement concrete.