Cement Filler Research Articles

The "Optimum Volume" of Acrylic Cement Filling for Treating Vertebral Compression Fractures: A Morphometric Study of Thoracolumbar Vertebrae.

Percutaneous vertebroplasty is a treatment option in vertebral compression fractures (VCF). The aim of the study was to propose the mathematical calculation of the "optimum volume" of acrylic cement filling of the vertebral body, depending on the severity of a fracture. Two hundred computed tomography (CT) scans of vertebral columns in healthy adult Caucasians were analyzed. Vertebral body width (VBW), vertebral body depth (VBD), vertebral body height (VBH), and vertebral body volume (VBV) were measured. The "optimum volume" of cement injections in mild (25% collapse) and moderate (40% collapse) VCF were calculated. We found that moving caudally from Th11 to L2, the mean values of the examined parameters increased: VBH from 22.6 to 26.0 mm, VBW from 34.0 to 39.5 mm, VBD from 28.1 to 30.9 mm, and VBV from 17.1 to 24.8 cm3. The calculated hypothetical "optimum volume" of cement injection increased from 7.4 to 10.0 cm3 in mild VCF and from 5.9 to 7.8 cm3 in moderate VCF, with some variability depending on the vertebral level and gender. These values are akin to those present in other past studies. We conclude that morphometric measurements, based on CT images, are a reliable source of practical anatomical savvy, which may be of help in spine surgery.

Effect of Almond Ash as Partial Replacement of Cement Filler on the Performance of HMA

Effect of Almond Ash as Partial Replacement of Cement Filler on the Performance of HMA

Influence of hyacinth plant as filler on mixed ac-wc (asphalt concrete - wearing course) with marshall test

Hyacinth plant is a destructive plant because the plant has the potential to make the swamps or rivers become shallow and damaging scenery. Though hyacinth plants can be exploited as a substitute for portland cement filler on road pavement Aspalt Concrete – Wearing Course mixture. This research is to know the optimum asphalt content and how much effect to the addition of ash hyacinth to Marshall result. The test specimens in this research were made with variation of 5%, 6% and 6.5% asphalt content and using five filler variations namely portland cement, as ash hyacinth, 50% hyacinth with 50% portland cement filler, 75% water hyacinth with 25% portland cement filler, and 25% hyacinth water mixture with 75% portland cement filler. From the results on Aspalt Concrete – Wearing Course mixture with the variation of bitumen content and filler variation done in the laboratory of Mercu Buana University, it is found that the optimum asphalt content of portland cement is 6.1%, the optimum asphalt content of ash hyacinth is 5.75%, 50% hyacinth with 50% portland cement filler is 6.1%, 75% water hyacinth with 25% portland cement filler is 6.0%, and a 25% ash hyacinth mixture with 75% portland cement filler is 6.0%.

Fracture analysis of sandstone with a single filled flaw under uniaxial compression

Natural rock joints with infilling materials such as clay, broken rock fragments, or even cement mortar infusion material are common in the field of rock engineering. The fracture behavior of a rock with a filled flaw is related to both the flaw inclination and mechanical properties of the infilling materials. In this study, uniaxial compression experiments were performed for sandstone specimens with different flaw inclinations varying from 0° to 90°, and four kinds of infilling conditions, including no filler, gypsum filler, cement filler, and resin filler were considered. The damage process of specimens was revealed and traced by acoustic emission (AE) and digital image correlation (DIC) to comprehensively understand the cracking evolution. Macroscopic cracking information was recorded with a high-resolution camera, and crack patterns were identified and classified. The influence of infilling material and flaw inclination on the sandstone cracking process was studied. The tensile stress was found to be suppressed due to the existence of infilling materials, and different infilling materials have different effects on the crack initiation stress. As a result, specimens with a filled flaw have larger crack initiation stress levels and smaller crack inclination angles than specimens with an unfilled flaw. The effects of infilling materials and flaw inclination angles on crack initiation are analyzed with a theoretical model based on the Coulomb friction law. The compressibility effect of infilling materials on the cracking behavior is also investigated through displacement and strain fields.

Influence of mix parameters on design of cold bituminous mix

In the absence of design uniformity, it is difficult to form reliable correlations between experimental results for Cold Bituminous Mixes (CBM) reported by different researchers/agencies/organizations. This paper presents a study on effects of various mix parameters such as aggregate gradation, method and level of compaction, variation in filler materials on performance of CBM. Dense (BC) and Gap (SMA) graded CBM were produced by both Marshall and gyratory method with varying level of compaction. Also, variations in filler materials (cement, lime, fly-ash) were done to evaluate the property of CBM. Finally, hot bituminous mixes were produced with same gradations (BC and SMA). A comparative study on test results has been made on basis of the Marshall Stability and air voids content of compacted mixes. It is observed that optimum residual bitumen content (ORBC) of cold mixes is not much affected by factors such as initial residual bitumen content (IRBC) and optimum total liquid content (OTLC). Rather, it mostly depends on the aggregate gradation. Considering all the selected parameters it is observed that only in case of gyratory compaction 3%–5% range of air voids can be achieved in CBM. Besides, though each and every parameter has contributed to increase the Marshall Stability of CBM, the most significant improvement as comparable with hot mixes is found to be caused by cement filler in comparison with other parameters. Also, higher load sustaining capacity of dense graded CBM is observed by its superior Marshall properties in comparison to gap graded CBM.

APPLICATION OF AGGREGATES OF NEPHELINE BEARING ROCKS IN INCREASED CORROSION RESISTANCE CONCRETE

Introduction. Diffusion of aggressive components of the external environment deeper into the concrete intensively flows through the contact surfaces and between the filler and the cement matrix. Therefore, it is better to apply active fillers that interact with the cement matrix on certain mechanisms for reducing the conductivity of the contact surfaces, which leads to the products durability.Materials and methods. Methods of mechanical testing, x-ray phase analysis, scanning electron microscopy were used for comparative studies of concrete corrosion resistance with the active filler (urtite) and with the inactive one (quartz sand).Results. This research indicates that the urtite filler significantly increases the strength and corrosion resistance of concrete in comparison with the traditional filler with quartz sand. The investigation of the contact zone of cement stone-aggregate with the usage of REM demonstrates that there are no corrosion products in the contact zone of urtite with the cement matrix, while the contact zone of quartz sand and its surface acquires corrosion products represented mainly by gypsum.Discussion and conclusion. The increased corrosion resistance of the fine aggregate concrete through the application of active filler on the basis of urtite provides lower conductivity of the contact surfaces between cement matrix and filler due to the chemical affinity of the rock-forming minerals of nepheline to calcium hydroxide. The additional factor that enhances the self-inhibition of acid corrosion is the formation of the gel-like layer of silica on the surface of nepheline, which inhibits the advancement of hydroxide ions due to the flow of electro-surface processes. Thus, the nepilnameciais fillers are appropriate to apply in concrete, which is used in the conditions of the chemical aggression of high intensity.

Improved biomechanics of two alternative kyphoplasty cementation methods limit vertebral recollapse.

The clinical efficacy of vertebral cement augmentation for compression fractures (VCFs) remains undetermined. Recent studies have shown that refracture and progression of deformity may occur after augmentation with significant clinical consequences. Vertebral body height loss following kyphoplasty has also been observed with cyclic loading. We hypothesized that height loss is partly due to lack of cement fill past the margin of cancellous bone created by balloon expansion with subsequent failure under load. The biomechanical characteristics of two alternative cementation techniques were compared to standard kyphoplasty in cyclically loaded cadaveric VCF constructs. Sectioned osteoporotic thoracolumbar cadaveric spines were compressed to 75% of anterior vertebral height. Specimens were then allocated to standard kyphoplasty, balloon pressurization (BP), with reinflation of the balloon after 50% cement injection, or endplate post (EP), with perforation of the cavity rim using an articulating curette prior to injection. Following cementation, each specimen was preconditioned and loaded over 100,000 cycles. All techniques improved vertebral height (p's < 0.005). The EP and BP techniques provided greater cement fill than the standard technique (p's ≤ 0.01). Normalized vertebral height loss following 100,000 cycles was reduced with the EP technique versus standard kyphoplasty (p < 0.04). Height loss was inversely correlated with cement fill (p < 0.03). No vertebral recollapse occurred with the EP technique in blinded radiographic analysis. Statement of clinical significance: The EP technique demonstrated improved biomechanical characteristics versus the standard technique in cadaveric osteoporotic VCF constructs with decreased recollapse following cementation. This technique may have increased efficacy in cases when kyphoplasty more substantially improves vertebral body height. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3225-3230, 2018.

Fillers to improve passing ability of concrete

Concrete possessing high‐passing ability needs to be flowable and cohesive. Hence, passing ability cannot be improved by solely adding superplasticizer, which increases both flowability and segregation of concrete simultaneously. Decreasing the maximum size of aggregates so that concrete segregates at lower cohesiveness is a possible but undesirable way as it narrows the aggregates' grading and decrease dimensional stability of concrete. With the same maximum size of aggregates, passing ability can be improved by raising the concurrent flowability‐segregation envelope of concrete. In this paper, fly ash and silica fume (cementitious fillers) and limestone (inert filler) were selected to replace cement partially and subsequently the passing ability of concrete was studied. From the results, it was evident that when either type of fillers were used, the passing ability and maximum limits of flowability and segregation achieved simultaneously increase. It is because these fillers are finer than cement that provides better filling effect to increase packing density and excess water leading to better flowability. Concurrently, the cohesiveness of concrete also increases as the content of fine particles increases. These allow concrete to hold the coarse aggregates more firmly when passing through narrow gaps, after which the concrete will keep flowing rapidly.

Friday, September 28, 2018 4:05 PM–5:05 PM abstracts: tumor and deformity: 250. Safety and efficacy of fenestrated pedicle screws with cement augmentation for spinal metastases: early experience with 292 screws

BACKGROUND CONTEXT Pedicle screw fixation can be a major challenge in patients with spinal metastases. The osteopenic nature of the vertebrae along with factors like previous radiation, immunosuppression, and marrow replacement by cancer affect the bone quality for fixation. Complications related to cement augmentation are known. We share our initial experience with the fenestrated screws. PURPOSE To demonstrate the efficacy and safety of this new screw technology in challenged fixation environements, specifically vertebral column metastases. STUDY DESIGN/SETTING Retropsective analysis from a prospective spine oncology database at a major cancer center. PATIENT SAMPLE We identified 38 consecutive patients who underwent posterior thoracic, lumbar, or sacral decompression and stabilization for pathologic fracture or cord compression (T1-sacrum) related to metastatic cancer over a 1 year period. OUTCOME MEASURES Preoperative SINS (spine instability neoplastic score), ASIA grade, cancer histology, radiation history, ECOG, and patient demographics were recorded and analyzed in a multivariable regression analysis. Postoperative CT was performed in all cases. CT was reviewed and cement extravasation was recorded at each level of pedicle screw placement in (1) the epidural space, (2) neural foramen, (3) paravertebral space, (4) lung, and (5) nearby vasculature including the segmental vessels and aorta. Complications and instrumentation or implant failure were recorded. Patient reported outcomes measures were recorded prospectively including EQ-5D, PROMIS-pain, PROMIS-disability, PROMIS-depression, Spine Oncology Study Group Questionnaire. METHODS IRB approval was obtained and a retrospective analysis was performed on a prospective spine oncology outcomes database. Fenestrated screws became available at our institution in November 2016. We identified 38 consecutive patients who underwent posterior thoracic, lumbar, or sacral decompression and stabilization for pathologic fracture or cord compression (T1-sacrum). In each case, postoperative CT imaging was performed within 24 hours of surgery. The investigators independently reviewed the studies evaluating for the extent of cement fill and extravasation. Chart review was performed for analysis of implant or construct failure and complications. RESULTS Thirty eight patients were identified and a total of 292 fenestrated screws were placed with an mean 7.21 screws implanted percase. The most common construct was two levels above and two levels below the site of worst vertebral fracture or cord compression. Cement extravasated into the (1) epidural space at six levels (2.97%), (2) neural foramen at three levels (1.49%), (3) paravertebral space at 37 levels (18.3%), (4) lung – 0, (5) nearby vasculature at 15 levels (7.42%). There was no cement spread to the aorta or vena cava. No patients developed a symptomatic radiculopathy from foraminal extent. No patient required reexploration, cement removal, or hardware revision. Follow-up ranged from 1 month to 15 months with no significant change invertebral body height at the instrumented levels by CT and x-ray. CONCLUSIONS Fenestrated screws with cement provide a safe and effective method for stabilization in the cancer patient.

Enchondromas and atypical cartilaginous tumors at the proximal humerus treated with intralesional resection and bone cement filling with or without osteosynthesis: retrospective analysis of 42 cases with 6\xa0years mean follow-up

BackgroundEnchondromas and atypical cartilaginous tumors (ACT) are often located at the proximal humerus. Most lesions can be followed conservatively, but surgical resection may alleviate pain, avoid pathological fractures, and prevent transformation into higher grade chondrosarcomas. Rigorous intralesional resection and filling with polymethylmethacrylate bone cement has been proposed for enchondromas but also for ACT, as an alternative for extralesional resection. We intended to analyze radiological, clinical, and functional outcome of this strategy and compare bone cement without osteosynthesis to bone cement compound osteosynthesis, which has not been analyzed so far.MethodsWe retrospectively analyzed 42 consecutive patients (mean follow-up 73 months; range 8–224) after curettage and bone cement filling with or without osteosynthesis. Exclusion criteria were Ollier’s disease and cancellous bone filling. Twenty-five patients only received bone cement. Seventeen patients received additional proximal humerus plate for compound osteosynthesis to increase stability after curettage. Demographics and radiological and clinical outcome were analyzed including surgery time, blood loss, hospitalization, recurrences, and complications. An additional telephone interview at the final follow-up assessed postoperative satisfaction, pain, and function in the quick disabilities of the arm, shoulder, and hand (DASH) score and the Musculoskeletal Tumor Society (MSTS) score. Statistics included the Student T tests, Mann-Whitney U tests, and chi-square tests.ResultsNo osteosynthesis compared to compound osteosynthesis showed smaller tumors (4.2 (± 1.5) cm versus 6.6 (± 3.0) cm; p = 0.005) and smaller bone cement fillings after curettage (5.7 (± 2.1) cm versus 9.6 (± 3.2) cm; p = 0.0001). A score evaluating preoperative scalloping and soft-tissue extension did not significantly differ (1.9 (± 0.9) versus 2.0 (± 1.0); rating scale 0–4; p = 0.7). Both groups showed high satisfaction (9.2 (± 1.5) versus 9.2 (± 0.9); p = 0.5) and low pain (1.0(±1.7) versus 1.9(±1.8); p = 0.1) in a rating scale from 0 to 10. Clinical and functional outcome was excellent for both groups in the DASH score (6.0 (± 11.8) versus 11.0 (± 13.2); rating scale 0–100; p = 0.2) and the MSTS score (29.0 (± 1.7) versus 28.7 (± 1.1); rating scale 0–30; p = 0.3). One enchondroma recurrence was found in the group without osteosynthesis. Complications (one fracture and one intra-articular screw) were only detected after osteosynthesis. Osteosynthesis had longer surgery time (70 (± 21) min versus 127 (± 22) min; p < 0.0001), more blood loss (220 (± 130) ml versus 460 (± 210) ml; p < 0.0001), and longer stay in the hospital (6 (± 2) days versus 8 (± 2) days; p = 0.004).ConclusionsIntralesional tumor resection was oncologically safe and clinically successful with or without osteosynthesis. Osteosynthesis did not reduce the risk for fracture but was more invasive.

Study on application of cement substituting mineral fillers in asphalt mixture

Abstract In order to investigate the potential of cement fillers applying in asphalt pavement instead of mineral fillers, this research did a comprehensive study, including the raw materials properties tests, mix design, and verification of mixture performance. Results show that in terms of the physical and volumetric properties, the cement fillers are similar with mineral fillers. The mix design process of asphalt mixture containing cement fillers can refer to the common asphalt mixture. The optimum asphalt/aggregate ratio was 5.0% for the materials and gradation selected in this research. The residual stability of immersion Marshall stability test was 78.9%, and the TSR of freeze–thaw splitting test was 74.4%. Both of them meet the specification requirements. The dynamic stability was 1169 time/mm, the seepage coefficient was 63.4 ml/min. These larger data than the required values demonstrated the good functional performance of asphalt mixture containing cement fillers, including the rutting resistance and the anti-permeable ability.

Influence of diatomite filler on rheological properties of porous asphalt mastic

ABSTRACTMineral filler is usually added into asphalt mixture to stiffen the asphalt binder and improve mixture strength. This is particularly important for open gradations such as porous asphalt which is known to have poor strength and durability because of its open nature and large air voids. The interactions that occur between asphalt binder and filler results in certain mastic properties that affect the mixture strength. In this study, the effect of different types of filler on the rheological properties of asphalt–filler mastics for porous asphalt were evaluated using the frequency sweep and multiple stress creep recovery (MSCR) tests. Hydrated lime, cement and diatomite with 2% content were selected to produce asphalt–filler mastic. The influence of diatomite filler was investigated and compared to the hydrated lime and cement fillers. Results indicated that the use of filler increased the stiffness of mastics. The MSCR test showed that hydrated lime and diatomite mastics exhibited the lowest non-recoverable compliance and high recovery than the original PG 76 binder and cement mastic. Diatomite mastic exhibits the best resistance to rutting at high temperatures and stress levels, verifying that the use of diatomite filler is favourable because of its high temperature properties.

Study of dry mixes with aluminate cements for self-leveling floors

In this article the results of the research of structure, shrinkage and physical and mechanical properties of concrete obtained from dry mixes based on aluminate cements for self-leveling floors are presented. The significant part of the cost of finishing works is the cost of mounting of the floors, as the quality of the floors determines not only the aesthetic comfort, but also the functionality of the room. The floors (especially, the floors of industrial, sports and so on buildings) must have the different properties: high strength and abrasion resistance, absolute resistance to cracking, dustless, hygienic etc. The main question of possibility of obtaining non-shrinking aluminate concrete is connected with the creation of ettringite using aluminate cement, gypsum and modern superplasticizers. Studies of free shrinkage of complex binder showed that binder could be classified as binder with compensated shrinkage. Cracking resistance of the composition is provided by the fact that the vast expansion in the initial stage of curing and shrinkage of the final stage is in 5...10 times lower than these values for gypsum and Portland cement. The problem of cracking resistance of thin-film coatings of cement compositions can be solved by binders with controlled shrinkage (expandable binders, whose shrinkage is compensated by the expansion). Resistance to cracking would be higher in the case when expansion and shrinkage are close not only in size, but also in the development time. The composition of dry mix for non-shrinking aluminate concrete consists of aluminate cement, gypsum, polycarboxylate superplasticizer and fractioned fine fillers. For experimental verification of the component composition of binder and the type of gypsum studies were conducted in a wide range of ratio of the components at a fixed value of the plasticity of the mixture. The structure of examined concrete is dense and has compensated shrinkage. Physical and mechanical properties of concrete are high enough and suited to the requirements of Russian construction norms (GOST).

Performance of Asphalt Concrete with Chrome and Hot Rolled Sheet with Chrome Using Portland Cement Filler and Prevent Exfoliation by Empirical Mechanism

A fine aggregate fraction that passes No. 200 is filler that affects the performance of a hot asphalt mixture. The usual Portland cement used on the asphalt mixture is Portland cement type 1. it will be tested using portland cement type1, type 2, type 3, and type 5. The chance of road damage is greater in wet than dry. The loss of asphalt or adhesion attachment can lead to weak bond between the asphalt/binder and the strength of interlocking and friction on the aggregate. If the binding strength is reduced or weak, the damage occurs on the aggregate and the asphalt consequently the structural value becomes reduced. Reduced structural values of weak bonds are often referred to as stripping processes. Aggregate attachment level with asphalt can be increased by adding anti stripping. The results showed that the best filler exprission of Portland cement type 1, type 2, type 3 and type 5, was the highest stability filler. This is owned by type 1 and type 5 filler. Portland cement type 1 type stabiltas value is 1,296.10 kg while the type 5 value has a stability of 1317.20 kg.

SUBSTITUSI FILLER PADA CAMPURAN ASPAL DENGAN FLY ASH DAN SERBUK BATU BATA

Asphalt concrete wearing course as a wear layer in highway pavement layer, Is the top layer in flexible pavement. In this research will be discussed on the use of Portland cement filler as a reference to compare filler replacement with fly ash and powdered brick with 100% fly ash, 100% powdered brick and 50% fly ash: 50% powder brick. The first step after the aggregate testing, the asphalt and filler material to be used, followed by the manufacture of the specimen with the specified asphalt content. After obtaining the optimum asphalt content for each different filler variation, a Marshall test was performed to obtain flow stability and density values. In this research we get the optimum asphalt content value of 5,5% for each specimen. The result of this research mixed with good quality using 100% Portland cement filler stability value of 112.19 kg and the lowest using filler 100% fly ash but the result still meet the specifications of clan. While the MQ value with 100% filler of brick powder under specification of Bina Marga is 213. So it can be concluded that a good filler for asphalt concrete wearing course mixture is with Portland cement.

Utility of cement injection to stabilize split-depression tibial plateau fracture by minimally invasive methods: A finite element analysis

BackgroundTreatment for fractures of the tibial plateau is in most cases carried out by stable fixation in order to allow early mobilization. Minimally invasive technologies such as tibioplasty or stabilization by locking plate, bone augmentation and cement filling (CF) have recently been used to treat this type of fracture. The aim of this paper was to determine the mechanical behavior of the tibial plateau by numerically modeling and by quantifying the mechanical effects on the tibia mechanical properties from injury healing. MethodsA personalized Finite Element (FE) model of the tibial plateau from a clinical case has been developed to analyze stress distribution in the tibial plateau stabilized by balloon osteoplasty and to determine the influence of the cement injected. Stress analysis was performed for different stages after surgery. FindingsJust after surgery, the maximum von Mises stresses obtained for the fractured tibia treated with and without CF were 134.9 MPa and 289.9 MPa respectively on the plate. Stress distribution showed an increase of values in the trabecular bone in the treated model with locking plate and CF and stress reduction in the cortical bone in the model treated with locking plate only. InterpretationThe computed results of stresses or displacements of the fractured models show that the cement filling of the tibial depression fracture may increase implant stability, and decrease the loss of depression reduction, while the presence of the cement in the healed model renders the load distribution uniform.

Performance Evaluation of Plant Produced Warm Mix Asphalt

Warm mix asphalt (WMA) is relatively a new technology which enables the production and compaction of asphalt concrete mixtures at temperatures 15-40 °C lower than that of traditional hot mix asphalt HMA. In the present work, six asphalt concrete mixtures were produced in the mix plant (1 ton each) in six different batches. Half of these mixes were WMA and the other half were HMA. Three types of fillers (limestone dust, Portland cement and hydrated lime) were used for each type of mix. Samples were then taken from these patches and transferred to lab for performance testing which includes: Marshall characteristics, moisture susceptibility (indirect tension test), resilient modulus, permanent deformation (axial repeated load test) and fatigue characteristics (third point flexural beam test). The obtained results indicated that the performance of WMA is enhanced when using the hydrated lime as filler in comparison with the limestone dust and Portland cement fillers. Better fatigue life was obtained for WMA using hydrated lime filler in comparison with HMA. Regardless the filler type, the Marshall properties of WMA satisfy the requirement of local specification, other properties of WMA were relatively lower than the HMA.&#x0D;

Comparative study on engineering properties and energy efficiency of asphalt mixes incorporating fly ash and cement

In this study, the effect of fly ash (FA) as an alternative filler mineral was evaluated regarding workability, structural performance, durability, and its sustainability when prepared using hot (HMA) and warm mix asphalt (WMA) technologies. The results revealed that workability of HMA and WMA samples containing FA are comparable to the mixes containing cement powder, yet the WMA mixes containing 4% Sasobit® prepared at 145 °C exhibited the highest workability, regardless of filler type. However, the compaction energy index (CEI) of WMA samples containing FA is more sensitive to the Sasobit® content variations at each mixing temperature. Besides, use of FA as an alternative filler mineral increased the resilient modulus up to 7.5% as compared to HMA and WMA containing cement powder. The tensile strength ratios of asphalt mixtures containing FA are not only satisfied the design criteria, but it is also higher than those of samples with cement filler. Use of WMA technology improves sustainability in the construction phase, while incorporation of FA filler decreases the greenhouse gas emissions during the raw material manufacturing stage. Therefore, synergistic effects of using the WMA technology and FA improve the sustainability of both construction and raw material processing within the cradle to gate phases. In conclusion, a higher workability and resilient modulus test result together with less environmental emission indicate that the WMA technology using Sasobit® and FA as an alternative filler are showing great potential for the production of eco-friendly asphalt pavement.

Study of Influence of Composite Materials Components on Properties of Concrete Mixtures and Concrete in Time Dynamics

It is accepted to call concrete a special construction mix which consists of several main components – most often, these are cement, water and various fillers. As a result of grout hardening, the artificial stone, used in many areas where durability, stability and durability are required, is formed. To improve the main characteristics of concrete, various additives are added to the mix. These substances are also capable of accelerating the speed of construction and reducing the funds expenditure. It is especially important to apply additives at the installation of coverings to airfields, at the construction of moorings, roads, at the laying of pools or during other hydraulic engineering constructions, and also at the construction of monolithic industrial facilities and houses. The article deals with the composition and quantity of complex organomineral additives, the duration and conditions for the formation of composites’ structure.

Spontaneous painful subungual thumb haematoma

We present the case of a 56-year-old man who presented to our accident and emergency department 15 years after a work-based injury to his left thumb.In January 2017, the patient...