Table of compressive strengths and corresponding compressive strength increase. Field mortar compressive strength test values are not representative of the actual compressive strength of mortar in the masonry wall and are not appropriate for use in predicting the compressive strength that would be attained by the mortar in the masonry. There is a small increase in compressive strength from the 5⁄8-inch to the 7⁄8-inch specimens since the 7⁄8-inch specimens are thicker than the diameter of the puncher. The objective of the research presented herein was to determine a correlation between the compressive strengths of mortar made from the same mix but using different specimen configurations. The reasons are (a) the cubes are thicker yielding lower compressive strengths; (b) the cubes are cured in non-absorbent molds having higher water content and therefore lower compressive strength; and (c) the cubes are tested under unconfined compression which results in lower compressive strength. How to Retrofit Inclined Columns Damaged Due to Earthquakes? 1000. For all cases, except for Type N mortar with a 5.1-inch flow, the compressive strength more than doubled when comparing cube strength to the typical mortar joint 3⁄8-inch-thick specimen strength. 1.0 ... flow of hydrau lic cement mortar ... significantly decrease the dry density of foamed concrete. Trial mixes must be made from the materials to be used at the construction site as specified in the project specifications and be prepared according to the strict specifications outlined in ASTM C270. VIP members get additional benefits. If you require more strength, then 1:4 ratio is best suited. VIP members get additional benefits. The fly ash bricks are comparatively lighter in weight and stronger than common clay bricks. Linear regression (LR) model can be considered one of the most common regression equations for the prediction of the compressive strength of cement mortar (Eq. To achieve a well disperse of NMK in cement mortar, 15 prism specimens with the dimension of 40 × 40 × 160 mm 3 were prepared to test compressive strength of NKCM at the age of 3, 14, and 28 days. A masonry wall is subjected to compressive loads from floors above it and should have sufficient strength to withstand it. Determination of Compressive Strength of Mortar, Procedure for Compressive Strength of Mortar, Calculations of Compressive Strength of Mortar, Final Setting Time of Cement as per IS:4031-Part 5, Compaction Factor Test for Concrete Workability – Method and Procedure. You will receive a link and will create a new password via email. Sizes/Grading of aggregates etc However for any mix ratio, compressive strength for the cube ( 50 square cms) should be around 60–70% of target strength. The normalized mean compressive strength is given. Please enter your email address. Cement stabilized earth blocks are found to have compressive strength in the range of 2–6 MPa and it is also observed that the compressive strength of cement mortar (1 : 6) adopted for the construction of masonry in developing countries is higher than that of the blocks [ 3 Influence of Mortar Cube Strength Variability on the Measured Compressive and Flexural Strengths of Clay Masonry Prisms, 5th International Brick and Block Masonry Conference, 05-10 October 1979, Washington D.C., U.S.A. STRUCTURE® magazine is a registered trademark of the National Council of Structural Engineers Associations (NCSEA). At the same time, five prism specimens with the dimension of 40 × 40 × 160 mm 3 were prepared to test total pore area of NKCM at the age of 28 days. Questions or comments regarding this website are encouraged: Contact the webmaster. Betomix 1-1-6 mortar mix contains Portland cement and hydrated lime, but no sand. Grades mentioned in the cement bags as 53/43 grade OPC/PPC in fact represent the strength of the cement. 1:5 ratio of mortar impart compressive strength of 5.0 N/mm2 after 28 days of cube testing. Take a look at the below table. During construction evaluation, mortar is tested to obtain values for comparison to the baseline values established during the preconstruction evaluation and to determine batch-to-batch mortar uniformity. Compressive Strength of Mortar -Mix Ratio and Cube Test. Research has been conducted to try to determine the compressive strength of in-situ mortar. why risk of efflorescence formation in cement based materials is high in coastal areas? Parsekian, G. A., Fonseca, F. S., Pinheiro, G. L., and Camacho, J. S. (2014). Web development and content management by C3 Ink™, a division of Copper Creek Companies, Inc. Before linking, please review the STRUCTUREmag.org linking policy. 1250. 479. how we increase the compressive strength of 7 th day in cementitious grout. or [50-mm] Cube Specimens)1 This standard is issued under the ﬁxed designation C 109/C 109M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. Mortars with six water content variations were made and a minimum of seven specimens were cast from each mortar batch to compare the compressive strength of cubes and cylinders. This industry has the potential to Take out the cubes from water just before testing. Elwell, D. J., and Fu, G. (1995). Sorry, you do not have permission to ask a question, You must login to ask question. Mortar is a combination of cement, sand mixed with water. Login to The Constructor to ask questions, answer people’s questions, write articles & connect with other people. 1500. Jessop, E. L., and Langan, B. W. (1979). The masonry strength can be estimated using Tables 1.6.2.1 and 1.6.2.2 in ACI 530-88. 1.6. Water content. Calculate Quantities of Materials for Concrete -Cement, Sand, Aggregates, Types of Foundation for Buildings and their Uses [PDF], Methods of Rainwater Harvesting [PDF]: Components, Transport, and Storage, Quantity of Cement and Sand Calculation in Mortar. Strength of Cement Strength of cement is the most important of all the cement properties. f m is the compressive strength of mortar in. Type N is the normal, general purpose mortar mix and can be used in above grade work in both exterior and interior load-bearing installations. The amount of water to obtain such a flow is significantly smaller than that used in the preparation of the mortar at the construction site. It is considered to be a general-purpose mix, useful for above grade, exterior, and interior load-bearing installations. I need it before january 8, 2011. The Table also shows the percentage increase in compressive strengths for cube mortar specimens compared to a 3⁄8-inch specimen. To find the compressive strength of standard cement sand mortar cubes, following are the apparatus and procedures of the test. thnks in advance. 3050. Mortar Mix (by Loose Volume) Compressive Strength at 28 days (in N/mm 2) Cement: Sand: MM 0.7: 1: 8: 0.7 to 1.5: MM 1.5: 1: 7: 1.5 to 2.0: MM 3: 1: 6: 3.0 to 5.0: MM 5: 1: 5: 5.0 to 7.5: MM 7.5: 1: 4: 7.5 to above All Rights Reserved. If vibrator is used, the period of vibration shall be 2 minutes at the specified speed of 12000±400 vibrations /minutes. Common mix ratio of mortar used in masonry works are 1:3, 1:4 and 1:6 of cement to sand ratio. compressive strength at 28 days, as per BS 5628 [3]. A property-specified mortar typically has three different values of average compressive strengths: one obtained during the trial-and-error development of the mix according to ASTM C270, one obtained during preconstruction evaluation, and one obtained during construction evaluation. The DPT allows for some simulation of mortar joint confinement. 2014). Mix the cement and sand in dry condition with a trowel for 1minitues and then add water. It is used for masonry works such as brick masonry and stone masonry and for plastering walls, columns etc. Type N mortar. 2000. It’s 1000 dollars. The Table shows the compressive strengths of the cubes that were tested for comparisons to the DPT results. Compressive strength at 7 days =……….N/mm2, Compressive strength at 28 days =……….N/mm2, which IS standard has been followed to carry out the design and test procedure of cement mortar cubes?. Before construction begins, the mortar mix must go through preconstruction testing evaluation. The smaller compressive strength of the cylinders was expected due to their higher slenderness ratio and the probability of a greater number of flaws and failure planes due to their greater size. ermm…i need some conclusion and discussion bout the mortar strength. 3000 The strength of 1:6 ratio of mortar after 28 days is 3.0 N/mm2. If the mortar is weak then also its compressive strength is very low but if the mortar is a strong one then its compressive strength is also very high.. 1900. A Step-by-Step Guide, Passive House: Reduce Energy Consumption in Your Building. Lost your password? it gives 7.5 N/mm2 of compression strength. 5.2.6 Compressive strength testing (Annex A6) of molded mortar cylinders and cubes establishes one of the characteristics of hardened mortar.Mortar compressive strength test values are not representative of the actual compressive strength of mortar in the assembly and are not appropriate for use in predicting the compressive strength that would be attained by the mortar in the masonry assembly. The strength can be increased upto 2.0 N/mm2 by decreasing one portion of sand. Specimen thickness influences the compressive strength of mortar. The property method of specifying mortar allows for construction flexibility but requires the mortar to have minimum average values of certain mechanical properties, including compressive strength. Contents: [ show] Austin Dam Failure: One of the Biggest Disasters in US History, Embodied Carbon in Construction: High Time to Reduce it, How to Become a Construction Contractor? In addition, cured cubes were cut to thicknesses of approximately ¼, 3⁄8, ½, 5⁄8, and 7⁄8 inch. Please I need the compressive strength of concrete made with cement replaced by laterite upto 10%, 20%, 30%, 40%,50% and cement replaced upto 10%, 20%, 30%, 40%,50% by mound soil (termite hill soil). So, masonry compressive strength should be enough to support the loads on wall. Mortar Designation Cement:Lime Ratio Sand Ratio Known as Mortar Class Compressive strength (MPa) (i) 1:0 to 0.251/ 4 3 1:3 M12 8 - 12 (ii) 1:0.5 4 1:1/ 2:4 M6 5 - 8 (iii) 1:1 6 1:1:6 M4 3.6 (iv) 1:2 8/9 1:2:9 M2 1.5 Private test is very expensive for me. The mortar utilized was prepared using the procedures listed in ASTM C305, Standard Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency. Mortar is analyzed for chemical composition. According to ASTM C780, Standard Test Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry, when the compressive strengths from cube and cylinder test specimens from the same mix are compared, the cylinder compressive strength is approximately 85% of the cube compressive strength. 0.49. 977. In general, the results indicate that as the flow increases, attributable to water content increases, the compressive strength decreases. It is … Assume that the compression load is 375 KN (1 Kg = 9.81 N) Cross Sectional Area – 15 x 15 = 225 Sqcm. Compressive Strength = (375 x 1000/225) = 1666/9.81 = 169.82 Kg/Sqcm. Once the minimum average values of the mechanical properties are obtained, the quantities of cementitious materials and aggregates used in the preparation of the laboratory mortar are converted to volumetric proportions for making the mortar at the construction site. 4800. The time of mixing shall not be < 3 minutes & not > 4 minutes. In most of the cases, however, research was done to determine the compressive strength of the mortar in existing historical structures, which typically were constructed with weak mortars with very low compressive strength. Values of the compressive strength of the mortar prismatic samples. Just add water. Mortar is a formed by amalgamating cement, sand mixed with water. 5250. The small discrepancies observed for Type N are due to normal variations of mortar testing (Jessop and Langan 1979). i.e. STRUCTURE magazine is the premier resource for practicing structural engineers. Report FHWA/NY/SR-95/199, Transportation Research and Development Bureau, New York State Department of Transportation. It has been found that coconut husk ash has compressive strength close to control in mortar on 7days of 15% and palm oil Husk has compressive strength close to control in concrete at 28days of 20%. 1.6. During construction evaluation, the mortar is tested and a compressive strength value is determined. 1101) is the original 4000 psi average compressive strength blend of portland cement, sand, and gravel or stone. In the field, masons add water until a desired workable consistency is achieved. The results clearly show that the thickness of the specimen affects the compressive strength of the mortar and, for the results presented herein, the compressive strength increased with decreased thickness. Both Type N and Type S mortar were used in this research. Mortar compressive strength is influenced by mortar water content at the time of set. How To Calculate Compressive Strength Of Concrete Value? It is applicable for production control, performance and compliance testing. 7.06cm cubes moulds (50cm2 face area), apparatus for gauging and mixing mortar, vibrator, compression testing machine etc. Also, the compressive strength … What are the important points of FIDIC Contract we should keep in mind during tendering? Compressive strength is a test routinely used to measure the end performance of hardened mortar. To get 1 cuyd of N mortar, you need 27 cubic feet of the components in a 1 to 1 to 6 proportion. – Formula. Several batches of mortars with different water content were mixed, and molded specimens of different configurations were made for compressive strength testing. The test involves making a horizontal cut in the mortar … If, however, the mortar compressive strength in the masonry assembly is erroneously compared to that of the mortar tested during construction evaluation, the research results presented herein confirm that the compressive strength of the standard mortar cube will be significantly lower than the compressive strength of the in-situ mortar. 2. Compressive strength test was carried out on mortar and concrete for 7, 21 and 28days. 2800. A property-specified mortar needs first to be developed in the laboratory, through a trial-and-error procedure, to determine a mix that meets the property specification of ASTM C270. For preconstruction testing, the mortar is mixed using the volumetric quantities of the materials to be used in construction and must have a consistency similar to that of the field mortar. 244. Local sand is used for the preparation of cement mortar. To achieve such a field consistency, the amount of water added is significantly greater than that used during the laboratory trial-and-error procedure to develop a suitable mortar mix. The following conclusions are made from the research presented: The results presented show that a 3⁄8-inch in-situ mortar joint will have significantly greater compressive strength over a cube specimen made of the same mortar and tested according to prescribed ASTM standards.■. About 6,000 years ago [citation needed], they used lime to plaster the pyramids at Giza.In addition, the Egyptians also incorporated various limes into their religious temples as well as their homes. The thicknesses used in this research were selected to provide a wider range, even though bed mortar joint thickness is typically specified as 3⁄8 inch with an allowable tolerance of plus or minus 1⁄8 inch. Compressive strength of mortar is determined by using 2 inch or 50mm cubes as per ASTM C109 / C109M – Standard Test Method for Compressive Strength of Hydraulic Cement Mortars. 97.7. All materials contained in this website fall under U.S. copyright laws. ... QUIKRETE® Concrete Mix (No. In addition, the mortar in a masonry joint is in a state of stress different from that of the cylinder or cube specimen tested for their unconfined compressive strength. The DPT involves the use of two steel rods tapered at the ends to create a circular loading surface with a ¾-inch diameter. The mortar shall be prodded 20 times in about 8 sec to ensure elimination of entrained air. Compression testing of concrete: cylinders vs. cubes. There is no ASTM standard to determine the compressive strength of mortar specimens extracted from a masonry assembly. Using 2.7 specific gravity combine aggregate and w/c of 0.55. Generally masonry structures are constructed as load bearing. The introduction of the material into the mixing bowl, however, was modified slightly to accommodate the use of bagged mortar mix instead of raw materials. What is the percentage of carbon in wrought Iron? Properties of Mortar Using Cubes, Prism Halves, and Cylinder Specimens, ACI Materials Journal, 111(4). Experience shows that if a specified recipe is followed, mortar with certain performance characteristics is consistently obtained. The obtained value should, however, not be used to make any judgment of the mortar compressive strength in the masonry assembly. Compressive Strength of Hydraulic Cement Mortars (Using 2-in. inch in US units and in MPa – mega pascals in SI units.This is usually called as the characteristic compressive strength of concrete fc/ fck. In most cases, the two batches with the same water content yielded nearly identical mortar flows, and they were simply combined. How to Inspect a Structure Using Acoustic Emission Testing? The Table also shows the percentage increase in compressive strengths for cube mortar specimens compared to a 3⁄8-inch specimen. 2500. The standard sand shall be of quartz, of light, gray or whitish variety and shall be free from silt. It engages, enlightens, and empowers structural engineers through interesting, informative, and inspirational content. The first phase of testing was organized to verify the compressive strength disparity between cube and cylinder specimens. Country Why Compressive Strength Test of Mortar is Important? 4050. Each type of mortar used three variations of water content, and two batches were made for each water content. Results of the Double Punch tests are shown in Figure 2. These results have significant implications related to the compressive strength of mortar in a masonry assembly. Compressive Strength of concrete cube = Maximum load/Area of the cube. Several 2-inch mortar cubes were cast: some tested according to ASTM C109 and some sliced to thicknesses of approximately ¼, 3⁄8, ½, 5⁄8, and 7⁄8 inch for double punch testing. Specimen shape influences the compressive strength of mortar. The strength of concrete greater than 70 MPa is classified into high strength concrete. Applicable Standards American Concrete Institute (ACI) Become VIP Member. Back to Main Page. The rate of loading should be 350 kg/cm2/minute and uniform. Comments posted to STRUCTURE website do not constitute endorsement by NCSEA, CASE, SEI, C3 Ink, or the Editorial Board. Compressive strength: The compressive strength of cement is determined by compressive strength test on mortar cubes compacted by means of a standard vibration machine. 53 Grade OPC Cement simply means that 28-days compressive strength of the cement-mortar cubes prepared out of that cement in a standard manner will be of 53 MPa. The quantity of water shall be (p/4+3)% of combined weight of cement and sand where, p is the % of water required to produce a paste of standard consistency determined earlier. However, flow is seldom paired to a specific water content. © 2009-2020 The Constructor. Water content affects the compressive strength of mortar. Mortar is specified by proportions or by properties. Testing should be done on their sides without any packing. For important masonry structures such as brick walls, 1:3 ratio is used. Highest strength of concrete 220 MPa has also been used in building applications. From Table 2, as expected, the values of compressive strength of the prismatic samples average 3.14 MPa, 5.79 MPa, and 9.98 MPa, for the weak, reference, and strong mortars, respectively. It is advisable to apply 2 inch or 50mm cubes as stated by ASTM C109 / C109M – Standard Test Method for Compressive Strength of Hydraulic Cement Mortars to define the compressive strength of mortar. Mortar is a mixture of cement and sand in a specified ratio on which the strength of the mortar depends. Table 1 is a general guide for selection of mortar type. Types of Masonry Cement & Mortar. Mortar is a combination of cement, sand mixed with water. Variable water contents were therefore used in this research to determine the degree to which the compressive strength of the mortar was affected. Pre-blended mortar mix was used to make all mortar to mitigate ingredient variability. The ultimate strength of Nano-cement mortar was gained at 1.25% of cement replacement. Different preferences of mortar fluidity may even exist among different masons. Type N mortar This uses a 1 / 1 / 6 mix and results in a mortar with a 750 psi compressive strength. To the knowledge of the authors, no attempt has been made to determine a correlation between the compressive strengths of a laboratory mortar and an in-situ mortar because of the difficulties associated with obtaining undisturbed specimens from masonry and the lack of a standardized procedure for testing such specimens. Add water and mix it until the mixture is of uniform colour. During the preconstruction evaluation, the mortar is tested to establish baseline values for comparative evaluation of the field mortar. fly ash bricks are better alternative to conventional burnt clay bricks in structural, functional and economic aspects. 2150. Net area compressive strength of concrete masonry units (psi) Net area compressive strength of masonry (psi) f m ’ Type M or S mortar. Water has an integral role in the compressive strength of mortar and is the sole determinant of fluidity. Sand must be added on the worksite. The values of the mortar’s mechanical properties, to be compared with the minimum specified values, are determined through laboratory testing according to the requirement prescribed in ASTM C270, Standard Specification for Mortar for Unit Masonry. Compressive strength of mortar is determined by using 2 inch or 50mm cubes as per ASTM C109 / C109M – Standard Test Method for Compressive Strength of Hydraulic Cement Mortars. Reprinting or other use of these materials without express permission of NCSEA is prohibited. fb = [conditioning factor] * [Shape factor] * [Declared mean compressive strength] Declared mean compressive strength is obtained from experimental data. are constructed for residential and other masonry buildings. The DPT determines the compressive strength of thin mortar specimens by means of compressing the center area of the specimen with steel rods. The values obtained during the mortar preconstruction evaluation shall not be compared to the values obtained during the development of the mix because, most importantly, during the mix development, the mortar is mixed to a drier consistency. Sampling, testing, or measurement of properties in the laboratory or in the field is not required of a proportion-specified mortar. Higher water content results in lower compressive strength. Cylinders and cubes exhibit different strengths even when made from the same mortar mix, and the use of either specimen configurations yields lower strengths than what would be attained if a specimen having the same size and configuration of a typical mortar joint could be reliably tested. the compressive strength values resulting from field sampled mortars are not required nor expected to meet the compressive strength of the property specification requirements of C270 as tested under laboratory conditions, nor do they represent the compressive strength of the mortar in the wall. Another general observation is that compressive strength increases with the decrease of mortar flow, or decreased water content. For a load bearing masonry construction, it is important to know the compressive strength requirement of masonry to withstand the load subjected on it. Type N mortar mix has a medium compressive strength and it is composed of 1 part Portland cement, 1 part lime, and 6 parts sand. Use for any general concrete work. These mortar slices were also used for compressive strength testing. Ratio of mix is 1:2:4. Cube vs. cylinder compressive strength. by. 1) [6]. The results show small discrepancies as the expected compressive strength of the Type N mortar with 5.6-inch flow appears to be slightly lower, the compressive strength of the Type S mortar with 5-inch flow appears to be slightly higher, and the cube compressive strength of the Type S mortar with 5-inch flow appears to be slightly higher. Test should be conducted for 3 cubes and report the average value as the test result for both 7day and 28 day compressive strength. 1300. After mixing the components of the mortar for the specified amount of time, a small mortar sample was used to perform a mortar flow test in accordance with ASTM C1437. Also presented are the approximate compressive strengths of a 3⁄8-inch-thick specimen for each mortar flow; these values were obtained from the interpolation of the values presented in Figure 2. Select a country…Åland IslandsAfghanistanAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelauBelgiumBelizeBeninBermudaBhutanBoliviaBonaire, Saint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBritish Virgin IslandsBruneiBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongo (Brazzaville)Congo (Kinshasa)Cook IslandsCosta RicaCroatiaCubaCuraÇaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland IslandsFaroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and McDonald IslandsHondurasHong KongHungaryIcelandIndiaIndonesiaIranIraqIsle of ManIsraelItalyIvory CoastJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKuwaitKyrgyzstanLaosLatviaLebanonLesothoLiberiaLibyaLiechtensteinLithuaniaLuxembourgMacao S.A.R., ChinaMacedoniaMadagascarMalawiMalaysiaMaldivesMaliMaltaMarshall IslandsMartiniqueMauritaniaMauritiusMayotteMexicoMicronesiaMoldovaMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNetherlands AntillesNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorth KoreaNorwayOmanPakistanPalestinian TerritoryPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarRepublic of IrelandReunionRomaniaRussiaRwandaSão Tomé and PríncipeSaint BarthélemySaint HelenaSaint Kitts and NevisSaint LuciaSaint Martin (Dutch part)Saint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSan MarinoSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia/Sandwich IslandsSouth KoreaSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyriaTaiwanTajikistanTanzaniaThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited Kingdom (UK)United States (US)UruguayUzbekistanVanuatuVaticanVenezuelaVietnamWallis and FutunaWestern SaharaWestern SamoaYemenZambiaZimbabwe, By registering, you agree to the Terms of Service and Privacy Policy .*.

What Does A Rabid Fox Sound Like, Missouri Acreage For Sale By Owner, Design For Reliability Ppt, Avenger Of Zendikar, Red Leicester Macaroni Cheese, Disadvantages Of Cloud Storage, Beyerdynamic Dt 1990 Pro Uk, Kant Limits Of Knowledge,