Compressive Strength Studies on Recycled Binder Concrete

Recycled materials are gradually utilized in concrete. This paper examines the use of recycled binder in concrete. The compressive strength tests on concrete incorporating recycled binder instead of cement were carried out after 7, 14, and 28 days of curing. Cement was replaced by the recycled binder in ratios of 10%, 20%, and 30% by weight. The results show that the compressive strength of concrete is strongly affected by the percentage of the recycled binder. It has been found that the compressive strength decreases linearly with the increasing content of recycled binder. The recycled binder does not affect the strength development of concrete. In order to apply recycled waste to concrete as a binder, it is necessary to perform supplement research with appropriate additives to compensate for the loss of the compressive strength.

Influence of Exogenous Variables on Intrusion Depth of PMMA Bone Cement: Revision of ISO 5833 Standard

Background: Poly (methyl methacrylate) (PMMA) bone cement is widely used to anchor total joint replacements to the contiguous bone. Among the clinically-relevant properties of this material is its intrusion depth (ID) because it indicates the potential for interdigitation of the curing cement into the interstices of the cancellous bone. ID is determined using procedures stipulated in ISO 5833. There is only one study in which ISO 5833 was examined critically, but only one exogenous variable was considered. Purpose: We carried out an extensive critical analysis of the ISO 5833 Standard with a view to making recommendations for revising it. Materials and Methods: 7 approved PMMA bone cement brands (covering low-, medium-, and high-viscosity brands) were used in two series of tests. In the first series, the influence of time at which ID was determined (relative to achievement of cement doughing time (DT)) was delineated. In the second series, the influence of three clinically-relevant variables on ID for each of these brands was determined and, then, response surface methodology was used to analyze the results. Results: ID results are given for both series of tests. Over the range of the variables used, the optimum IDs for a low-, medium-, and high-viscosity brand were computed to be 5.7 mm, 3.1 mm, and 2.4 mm, respectively. Conclusion: The findings allowed us to recommend that the following revisions be made to stipulations in ISO 5833 for determining ID: prior to running the ID test, store the cement unit at 1°C; 60 minutes after removing the cement unit from the storage medium, mix the cement powder and liquid, in a vacuum chamber, at 120 rpm; and determine ID 3 minutes after DT is achieved.

Kajian Perbandingan Penggunaan Berbagai Merek Semen Dengan Dan Tanpa Perawatan Terhadap Kuat Tekan Dan Kuat Lentur Beton Pada Perkerasan Kaku

[ID] Semen merupakan suatu bahan pembentuk beton yang berperan sangat penting untuk mencapai mutu yang direncanakan. Selain pemilihan jenis merek semen, salah satu cara untuk mendapatkan kualitas beton yang baik yaitu dengan cara melakukan perawatan. penelitian ini bertujuan untuk mengetahui sejauh mana kualitas tiga merek semen terhadap kuat tekan dan kuat lentur beton disamping itu juga bertujuan untuk mengetahui seberapa besar perbedaan kekuatan dari masing- masing merek semen terhadap beton yang dirawat dan tanpa dirawat. Pada penelitian ini menggunakan metode eksperimental yang sesuai dengan SK SNI T-15-1990-03. Penelitian ini menggunakan semen Padang, semen Holcim, dan semen Bosowa, dengan menggunakan jenis perawatan perendaman pada sampel beton, pengujian yang dilakukan adalah pengujian kuat tekan dan kuat lentur dengan mutu rencana fc 30 MPa dengan umur 7, 14, 28, dan 56 hari, untuk masing-masing umur dibuat 3 benda uji dirawat dan 3 benda uji tidak dirawat. Dari hasil uji kuat tekan rata-rata semen padang memiliki kekuatan 32,65 MPa, semen holcim 31,33 MPa dan semen bosowa 30,86 MPa. Sedangkan untuk pengujian kuat lentur semen padang 4,35 MPa, semen holcim 4,23 MPa dan semen bosowa 4,18MPa, sementara beton yang tidak dirawat memiliki nilai lebih rendah dari beton yang dirawat.. Dari hasil pengujian tersebut dapat dilihat bahwa pemakaian merek semen perlu diperhatikan karakteristiknya serta perawatan mempunyai konstribusi yang cukup besar dalam mendapatkan mutu beton hasil pelaksanaan. [EN] The cement concrete as product that consit of several element which is important for achieve the quality that be planed. To choose same kriteria for getting the good quality of concrete, one of way are choosing the brand of cement and doing curing. Therfore, the aim of this research is ro know about the strength of of each brand of cement toword cured and uncuret concrete. This research used cement padang, cement holcim, cement bosowa with soaking treatments of concrete samples. The used of the tests are compresive and bending strength of concrete with using quality plan fc’ 30 MPa and age range 7, 14, 28 and 56 days. The cement padang is better than others cement and by getting the the highest value also found cement Padang has the sensitivity to the curing. Cement Bosowa got high strength at the beginning of the age and for cement Holcim is relativity stable with the age. From the researh, knowed that is important the selection of cement brand and curing to get the good result consist of the quality by yhe first plan.