SELF-HEALING BITUMINOUS MATERIALS BY ADAPTIVE ENCAPSULATED REJUVENATORS SYSTEM IS A HOT TOPIC WITHIN ROAD MATERIALS. FOR THE FIRST TIME, THIS WORK EXPLORES THE NATURAL SPORES FOR THE ENCAPSULATION OF REJUVENATORS AS A NOVEL CONTROLLED RELEASE SYSTEM TO PROMOTE THE SELF-HEALING CAPABILITY IN AGED BITUMINOUS MATERIALS. TREATED SPORES WERE OBTAINED FROM NATURAL SPORES BY CHEMICAL PROCESSES. TO SYNTHESIZE SPORE-BASED MICROCAPSULES, FIRSTLY, SPORES WERE DEFATTED, AND THEN THE PROTEIN AND CELLULOSIC MATERIALS WERE REMOVED. SPORES WERE PROCESSED, AND SUNFLOWER OIL AS A REJUVENATOR WAS ENCAPSULATED INSIDE SPORE MICROCAVITIES BY ENCAPSULATING PASSIVE AND VACUUM LOADING TECHNOLOGIES. PHYSICOCHEMICAL AND MICROSTRUCTURAL PROPERTIES OF THE NATURAL SPORE FORMULATIONS WERE EVALUATED. CHANGES IN THE COMPOSITION OF THE SPORES AMONG THE PROCESS WERE STUDIED BY FTIR SPECTROSCOPY. THE MICROSTRUCTURE ANALYSIS SHOWED THAT THE SPORES AFTER TREATMENT WERE EMPTY, SHOWING THE COMPLETE REMOVAL OF ALL CONTENTS INSIDE, KEEPING INTACT MICROSTRUCTURE, AND PROVIDING LARGE CAVITIES FOR MOLECULAR LOADING. FURTHERMORE, SUNFLOWER OIL ENCAPSULATION EFFICIENCY INTO THE SPORE CAVITIES WAS CONSIDERABLY HIGHER WITH VACUUM LOADING THAN BY THE PASSIVE LOADING PROCESS. THE CONTROLLED RELEASE MECHANISM AND THE HEALING EFFICIENCY OF ENCAPSULATED REJUVENATORS IN THE SPORE CAPSULES WERE ALSO QUANTIFIED. IT WAS PROVED THAT THE PROPOSED APPROACH WAS ABLE TO CONTROL THE RELEASE OF THE REJUVENATOR WITH AN ATTRACTIVE BIOMATERIAL POSSESSING A VERY STRONG STRUCTURE. THE MAIN RESULTS PROVIDE THE BASIS FOR FURTHER EXPLORATION INTO THE ENCAPSULATION OF REJUVENATORS IN NATURAL PLANT SPORES AS A PROMISING NOVEL CONTROLLED RELEASE SPORE-BASED SYSTEM FOR THE SELF-HEALING OF BITUMINOUS MATERIALS.

THIS PAPER HAS BEEN PREPARED IN THE FRAME OF A RESEARCH FOCUSED ON THE DEVELOPMENT OF COLD MIX PAVEMENT MATERIALS MADE WITH CALCIUM-ALGINATE CAPSULES (CMC) INSTEAD OF WITH JUST BITUMEN EMULSION, AS IT IS NORMALLY MADE. THE INITIAL OBJECTIVE WAS TO REMOVE MOST OF THE WATER IN COLD MIX ASPHALT BY ENCAPSULATING BITUMEN DROPLETS. THE ENCAPSULATION METHOD ALLOWED THE PREPARATION OF POLYNUCLEAR CAPSULES WITH BITUMEN EMULSION ENCAPSULATED, WHICH MEMBRANE WAS MADE OF CALCIUM-ALGINATE. CAPSULES WERE MIXED WITH AGGREGATES AT THE AMBIENT TEMPERATURE. DURING MIXING, THE CAPSULES CONTAINING BITUMEN EMULSION WOULD BREAK, RELEASE THEIR CONTENT AND COAT THE AGGREGATES. TO STUDY CMC, AN EXTENSIVE EXPERIMENTAL PROGRAMME HAS BEEN CARRIED OUT TO EVALUATE THE EFFECT OF COMPACTION ENERGY, CEMENT CONTENT, CURING TIME AND BINDER TYPE ON THE MECHANICAL PROPERTIES OF CMC. IT WAS FOUND THAT CMC TEST SAMPLES INCREASED THEIR MARSHALL STABILITY LINEARLY WITH THE INCREASE OF THE COMPACTION ENERGY. TEST SAMPLES COULD BE DEMOULDED IMMEDIATELY AFTER COMPACTION. FURTHERMORE, THE MARSHALL STABILITY OF CMC INCREASED WITH THE CURING TIME, AND THE GENERAL STRENGTH IMPROVED WITH THE INCREASING AMOUNT OF CAPSULES IN THE MIXTURE. IT WAS FOUND THAT THE BITUMEN IN CMC DID NOT HAVE AN IMPORTANT ROLE ON THE STRENGTH OF THE PAVEMENT MATERIAL, WHICH CAME MAINLY FROM THE ALGINATE IN THE CAPSULES. IN SHORT, COLD MIX PAVEMENT MATERIALS MADE WITH CALCIUM-ALGINATE (CA-ALGINATE) CAPSULES IS A NOVEL MATERIAL FOR PAVEMENTS THAT HAS SHOWN POTENTIAL TO BE AN ALTERNATIVE FOR CONVENTIONAL COLD MIX ASPHALT MADE WITH BITUMEN EMULSION.

EL ENVEJECIMIENTO DEL CEMENTO ASFÁLTICO ES UNA DE LAS PRINCIPALES CAUSAS DE AGRIETAMIENTO EN LOS PAVIMENTOS ASFÁLTICOS. EN LOS ÚLTIMOS AÑOS SE HA LOGRADO UN AVANCE SIGNIFICATIVO EN EL PERFECCIONAMIENTO DE NUEVOS REJUVENECEDORES ENCAPSULADOS PARA MATERIALES ASFÁLTICOS, PROMOVIENDO EL DESARROLLO DE INNOVADORES PAVIMENTOS AUTORREPARABLES. EN ESTE ESTUDIO SE EVALUÓ LA PRODUCCIÓN Y CARACTERIZACIÓN DE CÁPSULAS DE ALGINATO QUE CONTIENEN ACEITE CRUDO DE PALMA COMO UN PROMETEDOR REJUVENECEDOR PARA LA AUTORREPARACIÓN EXTRÍNSECA DE CEMENTOS ASFÁLTICOS ENVEJECIDOS A LARGO PLAZO. PARA CARACTERIZAR EL ACEITE DE PALMA SE UTILIZARON ANÁLISIS TERMOGRAVIMÉTRICO (TGA-DTGA) Y REFLECTANCIA TOTAL ATENUADA (ATR)- FTIR.

THIS CHAPTER PROVIDES A COMPREHENSIVE SUMMARY OF THE SIGNIFICANT ADVANCES IN SELF-HEALING BITUMINOUS MATERIALS FROM THE ENGINEERING TECHNOLOGIES ASSOCIATED WITH PROMOTING THE AUTONOMOUS HEALING CAPABILITY IN THE ASPHALT PAVEMENTS TO THE LARGE-SCALE APPLICATIONS.

WASTE TYRES (WT) ARE A SIGNIFICANT FRACTION OF INDUSTRIAL WASTE AND A SOURCE OF ENVIRONMENTAL HAZARDS WITH LIMITED VALORISATION. TO REDUCE THIS PROBLEM, CURRENTLY THERE IS A GROWING INTEREST IN VALUING THE WT THROUGH PYROLYSIS TO OBTAIN MULTIFUNCTIONAL LIQUIDS TO IMPROVE THE RHEOLOGICAL AND SELF-HEALING PROPERTIES OF AGED BINDERS. THIS RESEARCH PROVIDES A COMPREHENSIVE STUDY ON USING WT MIXTURES AS PRECURSORS FOR ASPHALT REJUVENATORS BY MEANS OF PYROLYSIS AND DISTILLATION PROCESSES. TO THIS END, WT POLYMERIC FRACTIONS FROM LIGHT (WT-L) AND MINING TRUCKS (WT-M) WERE USED AS FEEDSTOCK AND CHARACTERISED FOR COMPOSITIONAL AND THERMAL PROPERTIES. ADDITIONALLY, MICROPYROLYSIS COUPLED WITH GAS CHROMATOGRAPHY/MASS SPECTROMETRY (PY-GC-MS) WAS USED TO IDENTIFY THE MAJOR PRODUCTS IN PYROLYSIS VAPOURS, TO ELUCIDATE THE REACTION MAPS DESCRIBING THERMAL DEGRADATION OF WTS AND TO PREDICT THE FEASIBLE REACTION CONDITIONS. THE PYROLYSIS LIQUIDS WERE PRODUCED AFTER A SCREENING OF REACTION CONDITIONS AND SUBJECTED TO DISTILLATION, FOLLOWING A RESPONSE SURFACE MODEL TO PRODUCE AN OPTIMISED PYROREJUVENATOR. THE RESULTS SHOWED THAT THE PYROLYTIC REJUVENATOR OBTAINED THROUGH PYROLYSIS AT 465 DEGREES C AND DISTILLATION CUTTING AT 160-200 DEGREES C IS MAINLY COMPOSED OF HYDROCARBONS AND AROMATIC SUBSTANCES (95.5%), WITH A SIGNIFICANT PROPORTION OF LIMONENE (33.71%). FURTHERMORE, THE PYROLYTIC REJUVENATOR EXHIBITED HIGHLY DESIRABLE PHYSICAL PROPERTIES IN THE CONTEXT OF ITS APPLICATION AND EXCELLENT OXIDATIVE STABILITY (85.7%). OTHERWISE, IT WAS DETERMINED THAT BITUMEN MIXTURES WITH 3%-6% DOSES OF PYRO-REJUVENATOR IMPROVED THE VISCOSITY, SOFTENING POINT, AND PENETRATION OF AGED BINDERS, RESTORING THEIR PHYSICAL PROPERTIES TO THE VIRGIN STATE. IN CONCLUSION, PYROREJUVENATORS CAN BE SUCCESSFULLY USED AS A PROMISING SOLUTION TO PRODUCE MORE DURABLE AND SUSTAINABLE PAVEMENTS WITH IMPROVED RHEOLOGICAL AND HEALING PROPERTIES.

ASPHALT PAVEMENTS AND BITUMINOUS COMPOSITES ARE MAJORLY DAMAGED BY BITUMEN AGING AND FATIGUE CRACKING BY TRAFFIC LOAD. TO ADD, MAINTENANCE AND REPARATION OF ASPHALT PAVEMENTS IS EXPENSIVE AND ALSO RELEASES SIGNIFICANT AMOUNTS OF GREENHOUSE GASES. THESE ISSUES CAN BE MITIGATED BY PROMOTING ASPHALT SELF-HEALING MECHANISMS WITH ENCAPSULATED REJUVENATORS. THE ABILITY OF THE REQUIRED MICROCAPSULES TO BE RESILIENT AGAINST HIGH TEMPERATURES, OXIDATION, AND MECHANICAL STRESS IS ESSENTIAL TO PROMOTE SUCH SELF-HEALING BEHAVIOR WITHOUT COMPROMISING THE FIELD PERFORMANCE OF THE ASPHALT PAVEMENT. THIS WORK PROPOSES, FOR THE FIRST TIME, THE USE OF EXTREMELY RESISTANT BIOBASED SPORES FOR THE ENCAPSULATION OF RECYCLED OIL-BASED REJUVENATORS TO PRODUCE MORE RESILIENT SELF-HEALING PAVEMENTS. SPORE ENCAPSULANTS WERE OBTAINED FROM NATURAL SPORES (LYCOPODIUM CLAVATUM) BY APPLYING DIFFERENT CHEMICAL TREATMENTS, WHICH ENABLED THE SELECTION OF THE BEST MORPHOLOGICALLY INTACT AND CLEAN SPORE ENCAPSULANT. THE PHYSICAL, MORPHOLOGICAL, AND PHYSICOCHEMICAL CHANGES WERE EXAMINED USING FLUORESCENCE IMAGES, ATR-FTIR, SEM, SIZE DISTRIBUTION, XRD, TGA AND DSC ANALYSES. SUNFLOWER OIL WAS USED AS THE ENCAPSULATED REJUVENATOR WITH AN OPTIMAL SOL COLLOIDAL MIXTURE FOR SPOROPOLLENIN?OIL OF 1:5 (GRAM-TO-GRAM). VACUUM, PASSIVE, AND CENTRIFUGAL ENCAPSULATION TECHNIQUES WERE TESTED FOR LOADING THE REJUVENATOR INSIDE THE CLEAN SPORES AND FOR SELECTING THE BEST ENCAPSULATION TECHNOLOGY. THE ENCAPSULATION EFFICIENCY AND THE PROFILES OF THE ACCELERATED RELEASE OF THE REJUVENATOR FROM THE LOADED SPORES OVER TIME WERE STUDIED, AND THESE PROCESSES WERE VISUALIZED WITH OPTICAL AND INVERTED FLUORESCENCE MICROSCOPY. VACUUM ENCAPSULATION WAS IDENTIFIED AS THE BEST LOADING TECHNIQUE WITH AN ENCAPSULATION EFFICIENCY OF 93.02 ± 3.71%. THE REJUVENATOR WAS SUCCESSFULLY ENCAPSULATED INTO THE CLEAN SPORES, AS OBSERVED BY OPTICAL AND SEM MORPHOLOGIES. IN AGREEMENT WITH THE TGA AND DSC, THE MICROCAPSULES WERE STABLE UP TO 204 °

THIS STUDY AIMED TO CHARACTERISE POLYNUCLEAR BIOCAPSULES CONTAINING LOW-COST REJUVENATING AGENTS FOR ASPHALT SELF-HEALING. CAPSULES CONSISTED OF A BIOPOLYMERIC MATRIX OF CALCIUM ALGINATE CONTAINING COOKING OIL AND MINERAL OIL AS REJUVENATING AGENTS, BEING SYNTHESISED USING IONIC GELATION THROUGH THE PUMPING DRIPPING TECHNIQUE. THE PHYSICAL-CHEMICAL PROPERTIES OF THE OIL-IN-BIOPOLYMER EMULSIONS AND THEIR STABILITY OVER TIME WERE STUDIED. THE MORPHOLOGICAL AND THERMOPHYSICAL PROPERTIES OF THE BIOCAPSULES, AS WELL AS THE ENCAPSULATION EFFICIENCY OF THE REJUVENATING AGENTS, WERE QUANTIFIED AND CHARACTERISED BY MICROSCOPIC TECHNIQUES AND LABORATORY TESTS. MAIN RESULTS SHOWED THAT EMULSIONS SHOULD BE USED FOR ENCAPSULATION PURPOSES WITHIN A PERIOD NO LONGER THAN 3H, REDUCING THE EFFECT OF INSTABILITY PHENOMENA. BESIDES, THE BIOPOLYMER-BASED POLYNUCLEAR CAPSULES PRESENTED UNIFORM SIZE, INTERNAL MULTICAVITY MICROSTRUCTURE RESULTING IN HIGH ENCAPSULATION EFFICIENCIES AND THERMAL STABILITY AT HIGH TEMPERATURES, PROVING THAT COOKING OIL AND MINERAL OIL CAN BE POTENTIALLY USED AS LOW-COST REJUVENATING AGENTS AND THERMALLY STABLE ADDITIVES FOR ASPHALT SELF-HEALING PURPOSES.

THIS STUDY EVALUATED THE EFFECT OF TWO ENCAPSULATION METHODS (I.E., DROPPING FUNNEL AND SYRINGE PUMP), TWO CONCENTRATIONS OF THE ALGINATE-BASED ENCAPSULATING MATERIAL (2%, AND 3%), AND THREE OILS AS BITUMEN REJUVENATORS (VIRGIN SUNFLOWER OIL, WASTE COOKING OIL, AND VIRGIN ENGINE OIL) ON THE MORPHOLOGICAL, PHYSICAL, CHEMICAL, THERMAL, AND MECHANICAL PROPERTIES OF ENCAPSULATED REJUVENATORS FOR ASPHALT SELF-HEALING PURPOSES. A GENERAL FACTORIAL DESIGN 2 × 2 × 3 WAS PROPOSED TO DESIGN 12 DIFFERENT CA-ALGINATE CAPSULES. SIGNIFICANT DIFFERENCES ON THE MORPHOLOGICAL, PHYSICAL, AND MECHANICAL PROPERTIES OF THE CAPSULES WERE ANALYSED BY THREE-WAY ANOVA AND TUKEY HSD POST HOC ANALYSES. THE EFFECT OF THE TYPE OF OIL ON THE SELF-HEALING CAPACITY OF CRACKED BITUMEN SAMPLES WAS ALSO EVALUATED. THE MAIN RESULTS SHOWED THAT THE DESIGN PARAMETERS AND THEIR INTERACTIONS SIGNIFICANTLY AFFECTED THE MORPHOLOGICAL, PHYSICAL, AND MECHANICAL PROPERTIES OF THE CAPSULES. CAPSULES SYNTHESISED VIA SYRINGE PUMP METHOD, WITH VIRGIN COOKING OIL AND 2% ALGINATE WAS THE MOST APPROPRIATE FOR ASPHALT SELF-HEALING PURPOSES SINCE ITS UNIFORM MORPHOLOGY, ENCAPSULATION EFFICIENCY UP TO 80%, THERMAL DEGRADATION BELOW 5% WT., AND COMPRESSIVE STRENGTH ABOVE THE REFERENCE ASPHALT COMPACTION LOAD OF 10 N. FINALLY, THE HEALING TESTS SHOWED THAT VIRGIN COOKING OIL CAN BE POTENTIALLY USED AS A REJUVENATOR TO PROMOTE ASPHALT CRACK-HEALING.

UNA DE LAS PRINCIPALES CAUSAS DEL AGRIETAMIENTO PREMATURO EN LAS MEZCLAS ASFÁLTICAS ES EL ENVEJECIMIENTO DEL CEMENTO ASFÁLTICO. DURANTE LOS ÚLTIMOS AÑOS SE HAN DESARROLLADO IMPORTANTES AVANCES EN NUEVOS REJUVENECEDORES ENCAPSULADOS PARA MATERIALES BITUMINOSOS, PERMITIENDO LA PRODUCCIÓN DE NUEVOS PAVIMENTOS AUTORREPARABLES CON UNA MAYOR VIDA ÚTIL. EN ESTE TRABAJO SE HAN PRODUCIDO CÁPSULAS DE ALGINATO CON ACEITE CRUDO DE PALMA COMO UN POTENCIAL REJUVENECEDOR PARA LA AUTORREPARACIÓN EXTRÍNSECA DE CEMENTOS ASFÁLTICOS ENVEJECIDOS A LARGO PLAZO. PARA CARACTERIZAR EL ACEITE DE PALMA SE UTILIZARON ANÁLISIS DE TERMOGRAVIMÉTRICO (TGA-DTGA) Y REFLECTANCIA TOTAL ATENUADA (ATR)-FTIR.

THIS STUDY AIMED TO SYNTHESISE ENHANCED BIOCAPSULES CONTAINING OIL AS AN ADDITIVE TO PROMOTE SELF-HEALING IN BITUMINOUS MATERIALS. THE CAPSULES CONSISTED OF A BIOPOLYMERIC MATRIX OF SODIUM ALGINATE AS ENCAPSULATING MATERIAL AND SUNFLOWER COOKING OIL AS A NON-HAZARDOUS REJUVENATING AGENT. OIL WAS INCORPORATED IN FIVE CONCENTRATIONS BY WEIGHT OF ALGINATE, 1:1, 1:3, 1:5, 1:7, AND 1:9, RESPECTIVELY. THUS, FIVE OIL-IN-WATER (O/W) EMULSIONS WERE PREPARED TO SYNTHESISE BIOPOLYMERIC CAPSULES VIA IONIC GELATION USING AN ENCAPSULATOR DEVICE THAT WORKS BY JET VIBRATION TECHNIQUE. THE PHYSICAL PROPERTIES, STABILITY AND DROPLET SIZE DISTRIBUTION WERE MEASURED IN THE O/W EMULSIONS USING MICROSCOPY TECHNIQUES AND LABORATORY TESTS. THE MORPHOLOGICAL AND THE PHYSICAL-MECHANICAL PROPERTIES OF THE BIOCAPSULES WERE ALSO EVALUATED. THE MAIN RESULTS SHOWED THAT THE O/W EMULSIONS INCREASED THEIR VISCOSITY AND PHYSICAL STABILITY WHEN INCREASED THE OIL CONTENT, REDUCING THEIR CREAMING RATE OVER TIME. THE SYNTHESISED BIOCAPSULES PRESENTED SPHERICAL MORPHOLOGY AND HIGH ENCAPSULATION EFFICIENCY. THE SIZE OF THE PRODUCED BIOCAPSULES WAS MAINLY DEPENDENT ON THE SELECTED NOZZLE SIZE, THE FLOW RATE AND VISCOSITY OF THE EXTRUDED O/W EMULSIONS, AND THE VIBRATIONAL FREQUENCY APPLIED AND CONTROLLED ON THE ENCAPSULATOR DEVICE. A REDUCTION IN THE ENCAPSULATED REJUVENATOR CONTENT WAS QUANTIFIED IN THE BIOCAPSULES, RESULTING IN A LOWER VOLUME AND HIGHER DENSITY AND COMPRESSIVE STRENGTH VALUES. FINALLY, THE CAPSULES EFFECTIVELY RESISTED THE LOAD ASSOCIATED TO ON-SITE COMPACTION IN A WAY THAT THEY CAN BE POTENTIALLY

MESENCHYMAL STEM CELLS (MSC) ARE RECOGNIZED FOR THEIR IMMUNOMODULATORY EFFECTS AND REGENERATIVE PROPERTIES, BEING PROMISING THERAPEUTIC AGENTS FOR A WIDE RANGE OF DISEASES. TO ENSURE A LOCALIZED EFFECT OF MSC IN THE ORGANISM BIOBASED HYDROGELS HAVE BEEN TESTED FOR THEIR ABILITY TO ACT AS A MATRIX-EMBEDDED TO IMPROVE MSC TARGETED DELIVERY. IN THIS CONTEXT, NANOCELLULOSE (NC) HAS BEEN USED FOR DRUG DELIVERY, SHOWING BIOCOMPATIBILITY AND DURABILITY IN TIME, BUT UNTIL NOW NC HAS NOT BEEN TESTED FOR MSC GROWTH EXPLOITING THE SIZE AND ALDEHYDE CONTENT OF NC. IN THIS STUDY, CELLULOSE NANOCRYSTALS (CNC), CELLULOSE NANOFIBERS (CNF) AND MICROFIBRILLATED CELLULOSE (MFC) WERE STUDIED AFTER ONE-POT OXIDATION AND FURTHER CROSSLINKING WITH CHITOSAN (MASS RATIO 1:5). SIZE AND ALDEHYDE CONTENT OF OXIDIZED NC SAMPLES WERE EVALUATED TO ANALYZE THEIR INFLUENCE ON THE HYDROGEL'S PROPERTIES. THE CROSSLINKED HYDROGELS WERE ANALYZED BY FESEM, SWELLING ABILITY, FTIR, COMPRESSION TESTS, THERMAL STABILITY, AND STABILITY IN CULTURE CELL CONDITIONS. OXIDIZED-MFC HYDROGEL IMPROVED THE MECHANICAL STABILITY AND SWELLING BEHAVIOR, BUT IT LACKS STABILITY AT CELL CONDITIONS POSSIBLY DUE TO ITS LOW ALDEHYDE CONTENT (0.54 MMOL/G). CONVERSELY, OXIDIZED CNF AND OXIDIZED CNC FORMED SUITABLE CROSSLINKED HYDROGELS FOR CELL ADHESION, AND FOR GROWING AND PROLIFERATING OF MSC 3D SPHEROIDS AFTER 120 H. HOWEVER, ONLY HYDROGEL WITH PO-CNF/CHITOSAN SHOWS ANTIBACTERIAL ACTIVITY AS WELL AS MSC PROLIFERATION.

ENCAPSULATED REJUVENATORS BASED ON SUNFLOWER OIL AND ALGINATE BIOPOLYMER HAVE RECENTLY GAINED ATTENTION TO PROMOTE SELF-HEALING IN ASPHALT MIXTURES. HOWEVER, THE COMPLEX INTERACTION BETWEEN THESE MILLIMETRE-SIZE CAPSULES AND THE ASPHALT MORTAR AND THE POTENTIAL EARLY RELEASE OF THE REJUVENATOR FROM THE CAPSULES COULD COMPROMISE THE MECHANICAL PERFORMANCE OF THE ASPHALT COMPOSITE. THIS STUDY EVALUATES THE EFFECT OF AN OPTIMISED ALGINATE CAPSULE DESIGN WITH SUNFLOWER OIL ON THE RHEOLOGICAL PROPERTIES OF SHORT-TERM AGED (STA) AND LONGTERM AGED (LTA) ASPHALT MORTARS. A TOTAL OF 15 CAPSULE DESIGNS WERE SYNTHESISED BY THE VIBRATING JET TECHNIQUE AND BASED ON FIVE OIL-IN-WATER (O/W) EMULSIONS VARYING THEIR BIOPOLYMER:OIL (B:O) MASS RATIO (1:1, 1:3, 1:5, 1:7, AND 1:9) AND THREE CACL2 2 SOLUTIONS (2%WT., 5%WT., AND 8%WT. OF DEIONISED WATER). MORPHOLOGICAL, PHYSICAL, THERMAL, AND MECHANICAL PROPERTIES OF EACH CAPSULE WERE STATISTICALLY EVALUATED TO SELECT THE OPTIMAL DESIGN. THE SELECTED CAPSULE WAS INCORPORATED TO STA AND LTA CYLINDRICAL ASPHALT MORTARS TO EVALUATE THEIR RHEOLOGICAL PROPERTIES, THROUGH THE DYNAMIC SHEAR MODULUS, USING THE DYNAMIC MECHANICAL ANALYSIS (DMA) TEST AND THEIR SUSCEPTIBILITY TO PERMANENT DEFORMATION USING A MODIFIED MULTI-STRESS CREEP RECOVERY (MSCR) TEST. THE MAIN RESULTS SHOWED THAT THE CAPSULES HAD SIZES BETWEEN 1.12 AND 1.64 MM WITH REGULAR SPHERICAL MORPHOLOGY. THE OPTIMUM CAPSULE DESIGN WAS THAT WITH A B:O RATIO OF 1:7 AND 5%WT. OF CACL2, 2 , WHICH PRESENTED A SIZE OF 1.54 MM, HIGH ENCAPSULATION EFFICIENCY AND THERMAL/MECHANICAL STABILITY. THE ADDITION OF THE OPTIMISED CAPSULE DESIGN TO STA AND LTA MORTARS RESULTED IN I) A SOFTENING EFFECT, SIGNIFICATIVELY REDUCING THE DYNAMIC SHEAR MODULUS AT LOWER TEMPERATURES, AND II) NO SIGNIFICANT IMPACT ON THE SUSCEPTIBILITY TO PERMANENT DEFORMATIONS.

THIS PAPER PRESENTS THE SELF-HEALING RESULTS OF ASPHALT MIXTURES BY THE ACTION OF CAPSULES CONTAINING SUNFLOWER OIL AS ENCAPSULATED REJUVENATOR. THREE DIFFERENT CAPSULE CONTENTS, 0.10, 0.25 AND 0.50% BY TOTAL WEIGHT OF THE MIXTURE, WERE ADDED TO THE SAMPLES. THE MECHANICAL AND THERMAL PROPERTIES OF CAPSULES HAVE BEEN EVALUATED. IN ADDITION, THE EFFECT OF THE CAPSULE ADDITION AND THE HEALING TEMPERATURE ON THE SELF-HEALING PROPERTIES OF ASPHALT MIXTURES HAVE BEEN EVALUATED THROUGH THREE-POINT BENDING TESTS ON THE CRACKED ASPHALT BEAMS WITH, AND WITHOUT, CAPSULES. THE TEST WAS IMPLEMENTED BY COMPARING THE STRENGTH RECOVERY OF THE BROKEN BEAMS AFTER HEALING TO THEIR ORIGINAL FLEXURAL STRENGTH. IT WAS PROVEN THAT THE CAPSULES CAN RESIST THE MIXING AND COMPACTION PROCESSES AND BREAK INSIDE THE ASPHALT MIXTURE AS A RESULT OF APPLYING EXTERNAL MECHANICAL LOADS, RELEASING THE ENCAPSULATED OIL. THE CAPSULES CONTENT IN ASPHALT MIXTURE HAS A SIGNIFICANT INFLUENCE ON THE HEALING LEVEL, WHERE A HIGHER CAPSULE CONTENT LED TO OBTAINING HIGHER HEALING LEVELS. LIKEWISE, ASPHALT WITH, AND WITHOUT, CAPSULES PRESENTS AN INCREASE OF THE HEALING LEVEL WHEN THE TEMPERATURE INCREASES. FINALLY, IT WAS PROVED THAT HEALING TEMPERATURE HAS HIGHER INFLUENCE ON THE HEALING LEVELS OF THE ASPHALT BELOW 40 °C.

IN THIS PAPER, THE EFFECTS OF LAYERED DOUBLE HYDROXIDES (LDHS) INCORPORATION ON THE AGEING RESISTANCE AND SELF-HEALING PROPERTIES OF ASPHALT BINDER WERE STUDIED. MATRIX ASPHALT (MA) AND LDHS MODIFIED ASPHALT (LMA) BINDERS WERE AGED BY SHORT-TERM THERMAL OXIDATION AND ULTRAVIOLET AGEING AND THEIR AGEING PERFORMANCE WAS CHARACTERIZED THROUGH THE ANALYSIS OF THE SARA FRACTIONS AND TEMPERATURE SWEEP TEST. FREQUENCY SWEEP TEST AND CAPILLARY FLOW TEST WERE CONDUCTED TO CHARACTERIZE THE FLUIDITY OF THE ASPHALTS, AND FATIGUE LIFE RECOVERY TEST WAS USED TO CHARACTERIZE THE ASPHALT SELF-HEALING PROPERTIES. THE MAIN RESULTS INDICATE THAT UNDER THE SAME AGEING CONDITIONS, THE LIGHT COMPONENT CONTENTS OF LDHS MODIFIED ASPHALT ARE HIGHER THAN THAT OF MATRIX ASPHALT AND THE COMPLEX MODULUS INCREMENT OF LMA IS LOWER THAN THAT OF MATRIX ASPHALT. IT MEANS THAT LDHS MODIFIED ASPHALT HAS BETTER ANTI-AGEING PERFORMANCE. BESIDES, LDHS MODIFIED ASPHALT HAS HIGHER FLUIDITY AND LOWER SELF-HEALING THRESHOLD TEMPERATURE THAN MATRIX ASPHALT BINDER UNDER THE SAME AGEING CONDITIONS, INDICATING THAT THE INCORPORATION OF LDHS CAN EFFECTIVELY RETARD THE REDUCTION OF ASPHALT FLOW CAPACITY DUE TO AGEING. IT WAS ALSO FOUND THAT ASPHALT BINDER CONTAINING LDHS HAD BETTER SELF-HEALING POTENTIAL DUE TO THE IMPROVEMENT OF THE AGEING RESISTANCE. IT WAS CONCLUDED THAT THE ADDITION OF LDHS CAN EFFECTIVELY IMPROVE THE AGEING RESISTANCE AND SELF-HEALING PROPERTIES OF ASPHALT BINDER.

THIS PAPER INVESTIGATES THE INFLUENCE OF THE TYPE AND AMOUNT OF RECYCLED METALLIC WASTE ON THE PHYSICAL AND MECHANICAL PROPERTIES OF CEMENT-BASED MORTARS. THE PHYSICAL AND MECHANICAL PROPERTIES OF CEMENT MORTARS, CONTAINING FOUR DIFFERENT AMOUNTS OF METALLIC WASTE (RANGED 4 TO 16% BY CEMENT WEIGHT), WERE EVALUATED BY MEASURING THE BULK DENSITY, TOTAL POROSITY, FLEXURAL AND COMPRESSIVE RESISTANCE, AND DYNAMIC ELASTIC MODULUS BY ULTRASONIC TESTS. ALL THE PROPERTIES WERE MEASURED ON TEST SPECIMENS UNDER TWO CURING AGES: 7 AND 28 DAYS. ADDITIONALLY, THE MORPHOLOGICAL PROPERTIES AND ELEMENTAL COMPOSITION OF THE CEMENT AND METALLIC WASTE WERE EVALUATED BY USING SCANNING ELECTRON MICROSCOPY (SEM), ENERGY DISPERSIVE X-RAY SPECTROSCOPY (EDXS), AND X-RAY FLUORESCENCE (XRF). MAIN RESULTS SHOWED THAT THE ADDITION OF METALLIC WASTE REDUCED THE BULK DENSITY AND INCREASED THE POROSITY OF THE CEMENT-BASED MORTARS. FURTHERMORE, IT WAS OBSERVED THAT FLEXURAL AND COMPRESSIVE STRENGTH PROPORTIONALLY INCREASED WITH THE METALLIC WASTE ADDITION. LIKEWISE, IT WAS PROVEN THAT ELASTIC MODULUS, OBTAINED BY COMPRESSIVE AND ULTRASONIC TESTS, INCREASES WITH THE METALLIC WASTE AMOUNT. FINALLY, BASED ON A PROBABILITY ANALYSIS, IT WAS CONFIRMED THAT THE ADDITION OF METALLIC WASTE DID NOT PRESENT A SIGNIFICANT EFFECT ON THE MECHANICAL PERFORMANCE OF THE CEMENT-BASED MORTARS.

THIS PAPER AIMS TO EVALUATE THE EFFECT OF METALLIC WASTE ADDITION ON THE ELECTRICAL, THERMOPHYSICAL AND MICROWAVE CRACK-HEALING PROPERTIES OF ASPHALT MIXTURES. WITH THIS PURPOSE, ASPHALT MIXTURES WITH TWO DIFFERENT TYPES OF METALLIC WASTE, STEEL WOOL FIBRES AND STEEL SHAVINGS, ADDED IN FOUR DIFFERENT CONTENTS, WERE TESTED. ELECTRICAL AND THERMOPHYSICAL PROPERTIES OF ASPHALT MIXTURE SPECIMENS WITH, AND WITHOUT, METALLIC WASTE WERE MEASURED. THE SPATIAL DISTRIBUTION OF THE METALLIC WASTE INSIDE THE ASPHALT MIXTURE SAMPLES WAS EVALUATED BY USING X-RAY COMPUTED TOMOGRAPHY. IN ADDITION, CRACK-HEALING PROPERTIES OF ASPHALT SAMPLES USING MICROWAVE RADIATION HEATING WERE ASSESSED AT TWO DIFFERENT HEALING TIMES, 30 S AND 40 S. TO QUANTIFY THE EFFICIENCY OF THE HEALING PROCESS, FIVE HEALING CYCLES WERE CARRIED OUT FOR EACH ASPHALT SAMPLE. THE MAIN RESULTS SHOWED THAT ASPHALT MIXTURES WITH SHAVINGS PRESENTED LOWER AIR VOID CONTENTS THAN MIXTURES WITH FIBRES. MOREOVER, FIBRES PRODUCED AN INCREASE IN THE ELECTRICAL CONDUCTIVITY OF THE MIXTURES BECAUSE LONG FIBRES IN THE MIXTURES FORM ELECTRICALLY CONDUCTIVE CHANNELS. IN CONTRAST, SHAVINGS DID NOT HAVE SIGNIFICANT EFFECT ON THE ELECTRICAL PROPERTIES OF THE MIXTURES. LIKEWISE, IT WAS PROVEN THAT METALLIC WASTE REDUCED THE THERMAL CONDUCTIVITY AND THE SPECIFIC HEAT CAPACITY OF ASPHALT MIXTURES. CONVERSELY, SHAVINGS DECREASED THE THERMAL DIFFUSIVITY OF ASPHALT MIXTURES REGARDLESS OF THEIR CONTENT. OVERALL, IT WAS FOUND THAT THE HEALING LEVEL REACHED BY THE ASPHALT MIXTURES TESTED BY MICROWAVE RADIATION DEPENDS ON THE HEALING TIME AND THE TYPE AND CONTENT OF METALLIC WASTE USED. CT-SCANS RESULTS PROVED THAT THE SPATIAL DISTRIBUTION OF METALLIC WASTE INSIDE THE ASPHALT MIXTURE SAMPLES WAS NOT UNIFORM AND PLAYED AN IMPORTANT ROLE IN THE ASPHALT SELF-HEALING PROPERTIES USING MICROWAVE RADIATION HEATING. (C) 2018 ELSEVIER LTD. ALL RIGHTS RESERVED.

NOWADAYS, REFURBISHING OF EXISTING STRUCTURES HAS GAINED INTEREST IN ORDER TO REDUCE BOTH THE CONSTRUCTION MATERIALS USED AND THE CONSTRUCTION AND DEMOLITION WASTE PRODUCTION. FOR THAT PURPOSE, THERE ARE SEVERAL METHODS FOR DEMOLISHING THE DAMAGED PARTS, BUT MOST OF THE ALTERNATIVES INVOLVE HIGH NOISE AND DUST PRODUCTION, WHICH ARE IN CONTRAPOSITION WHEN STRUCTURES ARE IN URBAN AREAS. AMONG ALL THE EXISTING METHODS, THIS PAPER STUDIES THE POSSIBILITY OF USING MICROWAVE HEATING AS A DEMOLITION METHOD, EITHER BY DAMAGING THE BULK MATERIAL OR THE MORTAR TO CONCRETE INTERFACE. WITH THAT IN MIND, THE EFFECT OF MICROWAVE HEATING TIME (RANGE 120?600?S) ON THE PHYSICAL, THERMAL, ELECTRICAL, MECHANICAL AND BONDING PROPERTIES OF STEEL FIBRE-REINFORCED AND NON-REINFORCED CEMENT MORTARS WAS ANALYSED. THE AIM OF THE PAPER IS TO ESTABLISH POSSIBLE CORRELATIONS BETWEEN THE MENTIONED PROPERTIES AND THE DAMAGE LEVEL CAUSED BY MICROWAVE HEATING. ALTHOUGH THE RESULTS PROVE THAT PORE PRESSURE INCREMENT DUE TO MICROWAVE HEATING CAN CAUSE THE REDUCTION OF FLEXURAL STRENGTH UP TO THE RUPTURE OF THE SPECIMENS, THIS FACT CANNOT BE EXTENDED TO ALL THE PROPERTIES OR MORTAR TYPES. THE FIBRE REINFORCEMENT PLAYS A KEY ROLE TO RESTRAIN THE DAMAGE. THERMAL CONDUCTIVITY AND ELECTRICAL RESISTIVITY ARE OBVIOUSLY DIFFERENT IN REINFORCED AND NON-REINFORCED MORTARS DUE TO THE INCLUSIONS OF THE METALLIC FIBRES. HOWEVER, AFTER UNDERGOING MICROWAVE HEATING THOSE PROPERTIES WERE NOT NOTICEABLY ALTERED NOR FOLLOW A TREND LINKED TO THE HEATING TIME. IT IS ASSUMED THAT THE WATER MIGRATION AND EVAPORATION PROCESSES ARE THE MAIN CAUSE. ALTHOUGH THE FLEXURAL STRENGTH REDUCTION WAS GRADUAL FOR NON-REINFORCED MORTARS UNTIL TOTAL FAILURE, THE REINFORCED SPECIMENS ONLY SHOWED A 13% OF REDUCTION FOR THE FIRST 120?S, REMAINING ALMOST CONSTANT AFTERWARDS. ALTHOUGH IT WAS PROVED THAT THE FIBRES INCREASE THE TEMPERATURE ON THE SPECIMEN SURFACE AND ITS ADHESION TO THE MATRIX IS ALTERED, THEIR CRACK BRIDGING EFFECT OVERCOME

IN THIS PAPER, POLYMERIC CAPSULES WITH SUNFLOWER OIL AS THE ENCAPSULATED REJUVENATOR WERE MANUFACTURED AND ADDED TO ASPHALT MIXTURES TO IMPROVE THEIR SELF-HEALING PROPERTIES. A CAPSULE CONTENT OF 0.5% BY TOTAL MASS OF MIXTURE WAS ADDED TO THE ASPHALT SAMPLES. PHYSICAL, THERMAL AND MECHANICAL PROPERTIES OF THE CAPSULES WERE EVALUATED. ADDITIONALLY, THE EFFECT OF THE MIXING ORDER AND THE AGEING TIME ON THE MECHANICAL STABILITY AND SELF-HEALING PROPERTIES OF ASPHALT MIXTURES WITH, AND WITHOUT, CAPSULES WERE EVALUATED THROUGH STIFFNESS MODULUS AND FLEXURAL STRENGTH TESTS. SELF-HEALING PROPERTIES OF ASPHALT MIXTURES WERE EVALUATED THROUGH THREE-POINT BENDING TESTS ON CRACKED ASPHALT BEAMS WITH, AND WITHOUT, CAPSULES. IN ADDITION, CAPSULES? DISTRIBUTION AND THEIR INTEGRITY INSIDE THE ASPHALT MIXTURES WERE ANALYSED USING X-RAY COMPUTED TOMOGRAPHY. THE MAIN RESULTS PROVED THAT THE CAPSULES CAN RESIST THE MIXING AND COMPACTION CONDITIONS AND BREAK INSIDE THE MIXTURE RELEASING THE ENCAPSULATED OIL IN SMALL VOLUMES. IN ADDITION, IT WAS OBSERVED THAT THE ADDITION OF CAPSULES DID NOT IMPROVE THE STIFFNESS MODULUS OF ASPHALT MIXTURES COMPARED TO MIXTURES WITHOUT CAPSULES, AND THAT THE MIXING ORDER AND THE AGEING TIME DID NOT HAVE A SIGNIFICANT INFLUENCE ON THE FLEXURAL STRENGTH OF THE MIXTURES. MOREOVER, THE HEALING LEVELS OBTAINED BY THE MIXTURES VARIED DEPENDING ON THE ORDER OF ADDITION OF CAPSULES, AND MIXTURES WITH CAPSULES SHOWED HIGHER HEALING LEVELS THAN MIXTURES WITHOUT CAPSULES. FINALLY, THE LEVELS OF HEALING FOR THE MIXTURES WITHOUT AGEING WERE GREATER THAN THOSE OF MIXTURES AFTER THE AGEING PROCESS.