Future-Oriented Chemical Admixture by Synthesis of Water-Reducer Components

2020 ◽  
Vol 58 (1) ◽  
pp. 78-80
Author(s):  
A. Suga
Keyword(s):  
Chemical Admixture

scholarly journals Monitoring of the Impact of Lithium Nitrate on the Alkali–aggregate Reaction Using Acoustic Emission Methods

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Justyna Zapała-Sławeta ◽  
Grzegorz Świt
Keyword(s):  
Acoustic Emission ◽  
Initial Reaction ◽  
Lithium Nitrate ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Acoustic Activity ◽  
Initial Stage ◽  
Chemical Admixture ◽  
Different Characteristics ◽  
The Impact

The study analyzed the possibility of using the acoustic emission method to analyse the reaction of alkali with aggregate in the presence of lithium nitrate. Lithium nitrate is a chemical admixture used to reduce adverse effects of corrosion. The tests were carried out using mortars with reactive opal aggregate, stored under the conditions defined by ASTM C227. The acoustic activity of mortars with a corrosion inhibitor was referred to linear changes and microstructure of specimens in the initial reaction stages. The study found a low acoustic activity of mortars with lithium nitrate. Analysis of characteristic parameters of acoustic emission signals, combined with the observation of changes in the microstructure, made it possible to describe the corrosion processes. As the reaction progressed, signals with different characteristics were recorded, indicating aggregate cracking at the initial stage of the reaction, followed by cracking of the cement paste. The results, which were referred to the acoustic activity of reference mortars, confirmed that the reaction of opal aggregate with alkali was mitigated in mortars with lithium nitrate, and the applied acoustic emission method enabled the detection and monitoring of ASR progress.

scholarly journals STUDY ON EFFECT OF CHEMICAL ADMIXTURE ON FLUIDITY OF CEMENT PASTE CONTAINING CARBON-FREE FLY ASH

2017 ◽  
Vol 71 (1) ◽  
pp. 610-617
Author(s):  
Masao ISHIDA ◽  
Yoshiaki SATO ◽  
Toshihiro OTANI ◽  
Kenji UEDA
Keyword(s):  
Fly Ash ◽  
Cement Paste ◽  
Chemical Admixture

scholarly journals Studi Penggunaan Bahan Aditif Dan Variasi Dosis Accelerator Terhadap Perkerasan Beton Yang Dipercepat (Studi Kasus Mutu Beton K-300)

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Suhaimi Suhaimi ◽  
R. Dedi Iman Kurnia
Keyword(s):  
Mix Design ◽  
Concrete Mix Design ◽  
Chemical Admixture ◽  
Concrete Mix ◽  
Mineral Additive

Penelitian ini bertujuan untuk mengetahui hasil pengujian kuat tekan awal beton kombinasi sikafume (mineral additive) dan variasi dosis penggunaan accelerator (chemical admixture). Penelitian ini menggunakan metode eksperimental. Adapun prosedur penelitian dimulai dengan studi literatur, dilanjutkan dengan persiapan material, pemeriksaan sifat fisis agregat, perencanaan campuran beton (concrete mix design), pembuatan dan perawatan benda uji, serta pengujian benda uji berupa pengujian slump dan pengujian kuat tekan serta analisis data. Berdasarkan hasil dan pembahasan penelitian terkait dengan nilai kuat tekan beton, maupun bentuk atau workability dan waktu perkerasan adalah sebagai berikut: 1) hasil uji kuat tekan beton kombinasi sikafume dengan variasi dosis penggunaan accelerator 1:2 memiliki nilai kuat tekan rata-rata sebesar 26,823 Mpa dan 31,280 Mpa untuk umur pengujian 24 dan 72 jam; 2) hasil uji kuat tekan beton kombinasi sikafume dengan variasi dosis penggunaan accelerator 1:3,5 memiliki nilai kuat tekan rata-rata sebesar 24,913 Mpa dan 30,643 Mpa untuk umur pengujian 24 dan 72 jam; 3) hasil uji kuat tekan beton kombinasi sikafume dengan variasi dosis penggunaan accelerator 1:5 memiliki nilai kuat tekan rata-rata sebesar 23,640 Mpa dan 30,325 Mpa untuk umur pengujian 24 dan 72 jam; 4) nilai slump yang diperoleh pada setiap variasi benda uji lebih besar dari yang direncanakan dalam mix design, yaitu nilai slump yang diperoleh termasuk katagori slump runtuh; dan 5) kombinasi sikafume dan variasi dosis accelerator dapat mempercepat waktu perkerasan dengan nilai kuat tekan rata-rata di atas 24,90 Mpa atau K-300 dalam waktu 24 dan 72 jam

scholarly journals Stabilisation of an erodible soil using a chemical admixture

2010 ◽  
Vol 163 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J. S. Vinod ◽  
B. Indraratna ◽  
M. A. A. Mahamud
Keyword(s):  
Chemical Admixture

Preparation of high impermeable and crack-resistance chemical admixture and its mechanism

2002 ◽  
Vol 17 (2) ◽  
pp. 70-73 ◽  
Author(s):  
Ding Qing-jun ◽  
Lu Lin-nu ◽  
Hu Shu-guang ◽  
He Yong-jia
Keyword(s):  
Crack Resistance ◽  
Chemical Admixture

scholarly journals The Effect of Various Polynaphthalene Sulfonate Based Superplasticizers on the Workability of Reactive Powder Concrete

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Anthony Torres ◽  
Federico Aguayo ◽  
Srinivas Allena ◽  
Michael Ellis
Keyword(s):  
Compressive Strength ◽  
Fresh Concrete ◽  
High Strength ◽  
Reactive Powder Concrete ◽  
Chemical Admixture ◽  
Lower Viscosity ◽  
Reactive Powder ◽  
The Impact ◽  
Polycarboxylate Ether ◽  
High Range

A superplasticizer is a type of chemical admixture used to alter the workability (viscosity) of fresh concrete. The workability of fresh concrete is often of particular importance when the water-to-cement (w/c) ratio is low and a particular workability is desired. Reactive Powder Concrete (RPC) is a high-strength concrete formulated to provide compressive strengths exceeding 130MPa and made of primarily powders. RPC materials typically have a very low w/c, which requires the use of a chemical admixture in order to make the material workable for placing, handling and consolidating. Superplasticizer are commonly used for this purpose. Superplasticizers are developed from different formulations, the most common being Polynaphthalene Sulfonate (PNS), Polymelamine Sulfonate (PMS) and Polycarboxylate Ether (PCE). This study investigates the impact of various PNS based superplasticizers on the compressive strength and rheological performance of a RPC mixture. Six different types of PNS based superplasticizers were used; three of various compositional strengths (high, medium, low range) from a local provider, and three of the same compositional strengths (high, medium, low) from a leading manufacturer. Specific properties assessed were the superplasticizers viscosity, concrete workability through the mortar-spread test, concrete rheology, and 7, 14, and 28 day RPC compressive strengths. Two mixtures were produced with two w/cm (0.20 and 0.15), which would subsequently increase the amount of superplasticizer needed, from 34.7L/m3 to 44.5L/m3. The results show that the name brand high range composition produced the overall highest spread, lowest viscosity, and a highest compressive strength at all ages tested. However, the local provider outperformed the name brand in the mid and low range compositions. Additionally, the rheology test also demonstrated that the name brand high range, and RPC produced with the name brand high range, had a lower viscosity at all angular speeds than the others tested.

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