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2021 ◽  
Vol 4 (2) ◽  
pp. 4-13
Author(s):  
Lorena Uriarte Herrera ◽  
◽  
Edwar Cieza Sánchez

El concreto es un material versátil, y debido a que se encuentra en todo tipo de construcción su demanda ha aumentado, generando así un incremento en la extracción de agregados, los cuales muchas veces no cumplen con las especificaciones técnicas. Se tuvo por objetivo evaluar comparativamente concretos elaborados con canteras de cerro y de río, para diseños con resistencia a la compresión (f’c) = 175 kg/cm2 y f’c = 210 kg/cm2. Se analizó las propiedades de los agregados tanto de cerro como de río, para calcular la dosificación de los componentes, utilizando la metodología del comité 211 del American Concrete Institute (ACI); luego de la elaboración de las probetas se realizó el curado y posteriormente se realizó los ensayos de resistencia a la compresión a los 7, 14 y 28 días. Se determinó que el concreto elaborado con agregados de río cumplen con los parámetros mínimos de resistencia a la compresión; sin embargo, los agregados en su mayoría no cumplen con la Norma Técnica Peruana (NTP) 400.037 y esto repercute de forma negativa en la resistencia del concreto. Por lo tanto, se recomienda la utilización de los agregados de cerro teniendo en cuenta las respectivas correcciones en el diseño de mezcla para obtener concretos con resistencias requeridas.


2021 ◽  
Vol 3 (4) ◽  
pp. 507-517
Author(s):  
Febrialdo Pratama Salinding ◽  
Jonie Tanijaya ◽  
Benny Kusuma

Karena adanya transformasi beban suatu susunan pada infrastruktur bangunan dapat menerima beban  diluar rencana awal, untuk itu perlu dilakukan  perkuatan struktur agar struktur bangunan tetap aman. Dalam penelitian ini penggunaan serat woven & non woven pada beton baru diharapkan bisa menambah kuat tekan, kuat tarik belah dan  modulus elastisitas terhadap beton konvensional. Mix design penelitian ini menggunakan metode American Concrete Institute (ACI). Sampel uji berjumlah 36 kemudian dibagi menjadi 3 variasi. Hasil penelitian ini telah menunjukkan penambahan kuat tekan, kuat tarik belah, dan modulus elastisitas. Kuat tekan untuk woven meningkat 29,485% % dan non woven meningkat 7,296% %, kuat tarik belah untuk woven meningkat 24,633% dan non woven meningkat 5,285%., modulus elastisitas untuk woven meningkat 20,924% dan non woven meningkat 9,356% . Untuk perbandingan kedua material, woven lebih kuat daripada non woven.


Author(s):  
Mohammed Taher Abdul Rahman Al-Haidari

This research included an applied study for the design of concrete mixtures by following the method of the American Concrete Institute (ACl) and the method of the Building Research Center in England (British method) to restriction which of these two methods is more suitable for use and application in the design of concrete mixtures when using local aggregate (gravel and sand taken from the area Badush and Aski Mosul), where job mixes were made using the mixing ratios obtained from these two methods, and a comparative study was made for the properties concrete resulting in the soft state (workability )and the hardened state (compressive resistance), and the results proved the following: A- In general, when discussing the results according to mixing ratios and workability levels, the method of the Building Research Center in England (the British method) gave higher results than the results obtained by the American Concrete Institute method (the American method) when using the above local aggregate whereas results shown increase in (workability) and Compressive strength. This increase amounts to the percentages shown in the table below: Compressive strength (%) Slump test (%) workability 10.48 14.40 Precipitation = 10-8 cm 12.10 21.40 Precipitation = 18-15 cm Table (1-1) B- It is possible to make another comparison, when fixing the proportion of water/cement, it turns out that the method of the Building Research Center in England (the British method) gives higher workability than the method of the American Concrete Institute (the American method) and for the same proportion of cement/ water, the American method gives Higher compressive strength than the British method. C- The building research center method is a more practical and applicable method more than the American Concrete Institute method because it takes the type of cement, the type of aggregate and other properties of the aggregate (especially particle shape) into consideration


2021 ◽  
Author(s):  
Robert Rodden ◽  
Eric Ferrebee

Inconsistency exists between common conversions from soil index properties (e.g., CBR) to a design k-value and a widespread nomograph that has become the definitive industry reference on the topic in the United States. Propagation of these inconsistencies into guidance from groups like the American Concrete Pavement Association (ACPA) and American Concrete Institute (ACI) Committees 330 and 360 has contributed to confusion in the industry. Advancements between the pavement and slab-on-ground communities have occurred in parallel but are inconsistent with each other, thus adding more confusion. ACPA developed a conversion set to better align the industry on a static k-value for design. While the ACPA model is included in StreetPave, PavementDesigner.org, and the ACPA App Library, outdated conversion equations are frequently used due to familiarity and lack of understanding of the underlying principles. This paper presents a summary of the industry's prior practices and recommendations, a detailing of the approach proposed by ACPA, and guidance on which k-value is recommended for design of concrete pavements and slabs-on-ground.


2021 ◽  
Vol 4 (2) ◽  
pp. 310-315
Author(s):  
Arman. A ◽  
Arif Oftan

Beton merupakan salah satu item yang memegang peranan penting dalam struktur baik itu gedung, jembatan, bendungan, dan bangunan sipil lainnya. Beton dapat diartikan sebagai campuran antara semen Portland atau semen hidraulik yang lain, agregat halus, agregat kasar dan air dengan atau tampa bahan tambah membentuk massa padat (SNI 03-2834-2000). Beton mutu tinggi (high strength concrete) atau sering di sebut juga beton kinerja tinggi memiliki kinerja dan sifat - sifat yang lebih  unggul dibanfingkan dengan beton normal. Menurut American Concrete Institute (ACI) Committee 363, beton mutu tinggi adalah beton dengan kuat tekan diatas 6000 Psi (40 MPa). Untuk meningkatkan kualitas beton perlu dilakukan berbagai upaya dan inovasi agar mendapatkan mutu beton yang maximal. Inovasi dilakukan dalam penelitian ini dengan menambahkan Zat Adiktif SP 337 dalam adonan beton. Berdasarkan brosur Fosroc, Conplast SP 337 baik untuk meningkatkan kekuatan atau untuk menghasilkan beton kemampuan kerja tinggi atau mengurangi kandungan semen beton atau untuk memperlambat waktu pengerasan beton. Penggunakan zat adiktif  fosroc sp 337 di dalam penelitian ini dengan komposisi 0,0%, 1,5%, dan 2,5% dari berat jenis semen. Setiap variasi campuran terdapat 3 sampel benda uji. Dari hasil pengujian kuat tekan terjadi kenaikan kuat tekan rata-rata perbedaan  nilai yang cukup jauh pada umur 7 hari antara campuran zat adiktif Fosroc SP 337 0% dengan kuat tekan  rata - rata sebesar 16,48 MPa, campuran  1,5%  kuat tekan rata - rata sebesar 21,89 MPa, dan 2,5% dengan kuat tekan rata - rata sebesar 24,19 MPa. Sedangkan pada umur pengujuan 28 hari kuat tekan rata - rata setiap variasi campuran Fosroc SP 337 hampir saling mendekati, ini dapat kita analisa pada tabel 4.19, 4.20, 4.21 dengan data campuran (0%) memiliki kuat tekan rata - rata 34,43 MPa, campuran (1,5%) memiliki kuat tekan rata 35,68 MPa, dan campuran (2,5%) memiliki kuat tekan rata-rata 38,89 Mpa. Hal ini diakibatkan oleh sifat zat adiktif Fosroc SP 337 yang mempercepat dan menambah kuat tekan di awal umur beton. Kuat tekan rata - rata paling tinggi ialah campuran 2,5%.


2021 ◽  
Vol 7 (1) ◽  
pp. 48-58
Author(s):  
Munawir Munawir ◽  
Khalid Khalid

Beton merupakan salah satu bahan konstruksi bangunan. Campuran beton terdiri dari semen, air, agregat dan bahan tambah bila diperlukan. Material semen dalam beton sangat penting dikarenakan semen berfungsi sebagai bahan pengikat antara agregat kasar dan agregat halus. Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan semen Portland Cement Composit  (PCC) dan semen Tipe I diproduksi oleh semen Andalas terhadap kuat tekan beton berdasarkan umur beton pada campuran beton dengan nilai Faktor Air Semen (FAS) 0,50 dan 0,55. Perencanaan campuran beton menggunakan metode American Concrete Institute 211.1-91. Ukuran maksimum agregat adalah 31,5 mm. Benda uji yang digunakan pada penelitian adalah silinder beton berdiameter 15 cm dan tinggi 30 cm. Pada penelitian ini umur pengujian kuat tekan adalah 3, 7, 14, 21 dan 28 hari dengan  FAS 0,50 dan 0,55. Jumlah sampel untuk semua FAS pada setiap pengujian kuat tekan beton adalah 30 buah benda uji untuk masing-masing tipe semen. Berdasarkan hasil pengujian kuat tekan rata-rata beton FAS 0,50 yang menggunakan semen tipe I untuk umur 3, 7, 14, 21 dan 28 hari berturut-turut adalah sebesar 193,34 kg/cm2, 203,72 kg/cm2, 229,18 kg/cm2, 248,99 kg/cm2  dan 272,57 kg/cm2. Sedangkan Untuk semen PCC pada umur yang sama kuat tekannya adalah sebesar 139,58 kg/cm2, 169,77 kg/cm2, 202,78 kg/cm2, 220,69 kg/cm2 dan 249,93 kg/cm2. Untuk FAS 0,55 yang menggunakan semen tipe I untuk umur 3, 7, 14, 21 dan 28 hari berturut-turut adalah sebesar 182,97 kg/cm2 , 202,78 kg/cm2, 218,81 kg/cm2, 235,79 kg/cm2 dan 267,85 kg/cm2. Sedangkan Untuk semen PCC pada umur yang sama kuat tekannya adalah sebesar 149,02 kg/cm2, 169,77 kg/cm2, 177,31 kg/cm2, 209,38 kg/cm2 dan 243,33 kg/cm2. Ditinjau dari jenis semen yang digunakan terlihat bahwa beton dengan menggunakan semen adalas tipe I perkembangan kuat tekan betonnya lebih tinggi dibandingkan dengan PCC baik pada FAS 0,50 dan 0,55 pada umur yang sama.


2021 ◽  
pp. 38-48
Author(s):  
Ric L. Gonzaga

This study discusses on the condition assessment of the profile and non-structural factors of the buildings in the University of Eastern Philippines was undertaken to determine the level of functionality of the building as perceived by the end users, to find out the serviceability of the buildings structure, and to assess the profile and non-structural factors of the buildings in the University of Eastern Philippines. The study utilized ocular/visual inspection, data and documents review, applying the instrument made by Coronilli [1], survey questionnaire as perceived by the end users, and the American Concrete Institute (ACI) guidelines on the condition of the selected buildings in the University of Eastern Philippines-Main Campus. Cracking of concrete are classified into structural and non-structural cracks. Non-structural cracking was observed in the buildings inspected and the College of Nursing is the most critical building in terms of cracks of the building. Furthermore, College of Science obtained 3.07 was perceived as most functional building according to the end users. The school buildings which are in need of repair is the College of Nursing buildings.


2021 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Shoib Bashir Wani ◽  
Tahir Hussain Muntazari ◽  
Nusrat Rafique

The various approaches, established for concrete mix design, are not universal because design mixes are explicit to local climate, available materials, and type of exposure. The new-generation mix design method should be developed based on the performance criteria. The concrete strength obtained from the designed concrete mix and optimum cement content should not be considered as the only parameter for the suitability of the concrete mix. This study was carried to compare the proportioning of concrete mixes obtained by following procedures of Indian Standard (IS), American Concrete Institute (ACI) and British Standard (BS) of concrete mix design without the use of admixtures to validate for use in a moderate climate like Kashmir, India. The concrete mixes have been prepared with the necessary 28 days resistance in compression as “15 MPa, 20 MPa, 25 MPa, 30 MPa and 35 MPa”. The assessment of water-cement (w/c) ratio; cement, water, fine aggregate (FA) and coarse aggregate (CA) proportion was carried. The w/c ratio among all formulated mixes is significantly high in the BS method and low for IS method. The BS method uses less quantity and IS method uses the maximum quantity of cement. In addition, the ratio of total aggregate content (TAC) and the aggregate-cement ratio is higher in BS design method as compared to IS and ACI design methods. The aggregate content in ACI mix design appears to be consistent and it added to the relative high compressive strength. The specimens cast following BS guidelines failed to attain the target mean strength (TMS) due to a higher volume of aggregate content, high w/c proportion, less quantity of cement in the mix. The specimens cast by ACI and IS mix design upon compression testing showed higher results than the calculated TMS. The cost analysis per cubic meter of concrete revealed that IS and ACI mix proportioning are expensive than BS method. The IS procedure results in dense concrete followed by ACI procedure. It is expected that with a comprehensive investigation on selected design parameters concentrating more on local challenges, the present study will floor the way for the development and adoption of performance-based design mix selection for moderate climate.


2021 ◽  
Vol 3 (1) ◽  
pp. 47-54
Author(s):  
Iksal Lagalung ◽  
Jonie Tanijaya ◽  
Suryanti Rapang Tonapa

Bottom ash (abu dasar) adalah sisa pembakaran batu bara di Indonesia di kategorikan sebagai limbah (B3). Kandungan logam berat dalam limbah B3 menyebabkan pencemaran lingkungan. Bottom ash melimpah dan kurang dimanfaakan. Oleh karena itu berbagai inovasi dilakukan peneliti agar penggunaan kontruksi beton layak digunakan terhadap pengaruh hujan asam serta pengelolaan bottom ash sebagai material konstruksi beton. Pada penelitian ini persentase substitusi bottom ash agregat halus sebanyak 0%, 25%, 35% dapat digunakan untuk campuran beton dengan perendaman asam sulfat pH-4. Dengan benda uji yang digunakan berukuran 15 cm x 30 cm dan 60 cm x 15 cm x 15 cm sebanyak 45 sampel, menggunakan metode American Concrete Institute (ACI). Pengujian tersebut berupa pengujian kuat tekan. kuat tarik belah dan kuat lentur beton dengan mutu rencana sebesar 30 MPa. Pada umur 28 hari didapatkan nilai kuat tekan sebesar 32,727 Mpa, 33,859 Mpa, 36,782 Mpa. Beton dengan substitusi bottom ash sebagai agregat halus dengan variasi 0%, 25% dan 35% mengalami peningkatan kekuatan seiring bertambahnya persentase substitusi bottom ash dimana semakin tinggi persentase substitusi bottom ash maka kekuatan beton semakin tinggi, sehingga dapat dikatakan bahwa persentase substitusi bottom ash berbanding lurus dengan kekuatan beton.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 351
Author(s):  
Abathar Al-Hamrani ◽  
Murat Kucukvar ◽  
Wael Alnahhal ◽  
Elsadig Mahdi ◽  
Nuri C. Onat

A primary concern of conventional Portland cement concrete (PCC) is associated with the massive amount of global cement and natural coarse aggregates (NCA) consumption, which causes depletion of natural resources on the one hand and ecological problems on the other. As a result, the concept of green concrete (GC), by replacing cement with supplementary cementitious materials (SCMs) such as ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF), and metakaolin (MK), or replacing NCA with recycled coarse aggregates, can play an essential role in addressing the environmental threat of PCC. Currently, there is a growing body of literature that emphasizes the importance of implementing GC in concrete applications. Therefore, this paper has conducted a systematic literature review through the peer-reviewed literature database Scopus. A total of 114 papers were reviewed that cover the following areas: (1) sustainability benefits of GC, (2) mechanical behavior of GC in terms of compressive strength, (3) durability properties of GC under several environmental exposures, (4) structural performance of GC in large-scale reinforced beams under shear and flexure, and (5) analytical investigation that compares the GC shear capacities of previously tested beams with major design codes and proposed models. Based on this review, the reader will be able to select the optimum replacement level of cement with one of the SCMs to achieve a certain concrete strength range that would suit a certain concrete application. Also, the analysis of durability performance revealed that the addition of SCMs is not recommended in concrete exposed to a higher temperature than 400 °C. Moreover, combining GGBFS with FA in a concrete mix was noticed to be superior to PCC in terms of long-term resistance to sulfate attack. The single most striking observation to emerge from the data comparison of the experimentally tested beams with the available concrete shear design equations is that the beams having up to 70% of FA as a replacement to OPC or up to 100% of RCA as a replacement to NCA were conservatively predicted by the equations of Japan Society of Civil Engineers (JSCE-1997), the American Concrete Institute (ACI 318-19), and the Canadian Standards Association (CSA-A23.3-14).


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