scholarly journals Influence of Water-Repellent Treatment with Silicon Resin on Properties of Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yupeng Tian ◽  
Penggang Wang ◽  
Tiejun Zhao ◽  
Zhiming Ma ◽  
Zuquan Jin ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Permeability ◽  
Effective Means ◽  
Cementitious Materials ◽  
Water Repellent ◽  
Hydration Reaction ◽  
Concrete Durability ◽  
Durability Properties ◽  
Cement Based Materials ◽  
Silicon Resin

Although studies on water-repellent properties of silicon resin (SR) on cement-based materials have received tremendous attention around the world in recent years, they mainly focus on individual properties of water-repellent concrete treated with SR such as strength and water permeability resistance. However, to date, a systematic and comprehensive investigation is missing. The current study therefore investigates the influence of SR on the durability properties of cementitious materials by adding SR emulsion into integral concrete mixture and coating concrete surface with SR. The microscopic and mechanical properties and the durability performance were tested on the integral SR water‐repellent concrete (C-ISR) and SR surface water-repellent concrete (C-SSR). The obtained results indicate that SR application has no impact on hydration reaction and corresponding composition of cement-based materials, while SR addition leads to a reduction in strength and early shrinkage of cement mortar because the added SR delays the hydration reaction. Water-repellent treatment via SR can significantly reduce the water permeability of concrete, which is more apparent for surface water-repellent treatment (SSR). Furthermore, the durability properties were investigated, and the results indicate that integral SR water-repellent treatment (ISR) possesses better properties than SSR, which suggests water-repellent treatment via surface coating as an effective means to improve concrete durability.

scholarly journals A Review on Application of Formaldehyde in Cement-Based Materials

2021 ◽  
Keyword(s):  
Construction Industry ◽  
Construction Material ◽  
Cementitious Materials ◽  
Flow Strength ◽  
Durability Properties ◽  
Cement Based Materials ◽  
Strength And Durability ◽  
The Impact ◽  
Flooring Materials ◽  
Nose And Throat

Abstract. Formaldehyde is environment contamination, which causes irritation in the eyes, nose, and throat with concentration above 1.0ppm. But still, it is used as a construction material as an admixture and furthermore to make paints, adhesives, pressed wood, and flooring materials, etc. This paper reviews the impact of formaldehyde in the cement on flow, strength, and durability properties. In this most of the researchers studied the water reducing nature of formaldehyde-based cementitious materials (FBCM) because of its repulsive property, that can ensure improved workability and provides good mechanical strength. Finally, the challenges in the application of formaldehyde in cement-based materials are discussed to conclude some future scope in the field of the construction industry to use formaldehyde in cement.

Using of Untreated Carbon Nanotubes in Cement Compositions

2016 ◽  
Vol 865 ◽  
pp. 6-11 ◽  
Author(s):  
Kateryna Pushkarova ◽  
Maryna Sukhanevych ◽  
Artur Martsikh
Keyword(s):  
Carbon Nanotubes ◽  
Cement Paste ◽  
Cementitious Materials ◽  
Positive Influence ◽  
Mechanical Tests ◽  
Strength Characteristics ◽  
Concrete Durability ◽  
Cement Mortars ◽  
Optimum Decision ◽  
Cement System

One of the most important problem of concrete durability is increasing of waterproofing. Researches are devoted studying of cement mortars modified by carbon nanotubes, dispersed in plasticizers solutions. Were investigated physico-mechanical properties of cement paste, cement-sand mortar into which structure entered untreated carbon nanotubes (production of plant TM "Spetsmash" Kyiv, Ukraine) in various quantity. Were used as plasticizers in cement compositions additives substances of the various chemical nature – naphtaleneformaldehyde, melamineformaldehyde and polycarboxylate. Quantity of untreated nanotubes varied from 0,5%; 1,0% and to 1,5%. Concentration of additives was accepted taking into account recommendations of producers and made about 1% from the weight of cement. Were studied some technological processes of introduction untreated carbon nanotubes in cement system and is shown that the way of introduction of nanomodifiers has essential impact on strength characteristics of cementitious materials. Optimum decision introduction of untreated carbon nanotubes is using its in dispersion plasticizer of the working concentration prepared in an ultrasonic dispergator is established. Results of physico-mechanical tests of cement paste and cement-sand mortar showed positive influence at introduction of untreated carbon nanotubes as cement modifiers on strength characteristics of samples. Resalts is shown that the nanomodifier, used quantity about 1% in solution of lignosulfonate with polycarboxylate and melamineformaldehyde plasticizer has great impact on strength characteristics.

Water permeability of unsaturated cementitious materials: A review

2021 ◽  
Vol 302 ◽  
pp. 124168
Author(s):  
Kai Li ◽  
Li Xu ◽  
Piet Stroeven ◽  
Caijun Shi
Keyword(s):  
Water Permeability ◽  
Cementitious Materials

Research Progress on the Hydration of Portland Cement with Calcined Clay and Limestone

2021 ◽  
Vol 1036 ◽  
pp. 240-246
Author(s):  
Jin Tang ◽  
Su Hua Ma ◽  
Wei Feng Li ◽  
Hui Yang ◽  
Xiao Dong Shen
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Research Progress ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Early Hydration ◽  
Calcined Clay ◽  
Dense Microstructure

The use of calcined clay and limestone as supplementary cementitious materials, can have a certain influence on the hydration of Portland cement. This paper reviewed the influence of limestone and calcined clay and the mixture of limestone and calcined clay on the hydration of cement. Both limestone and calcined clay accelerate the hydration reaction in the early hydration age and enhance the properties of cement. Limestone reacts with C3A to form carboaluminate, which indirectly stabilized the presence of ettringite, while calcined clay consumed portlandite to form C-(A)-S-H gel, additional hydration products promote the densification of pore structure and increase the mechanical properties. The synergistic effect of calcined clay and limestone stabilize the existence of ettringite and stimulate the further formation of carboaluminate, as well as the C-(A)-S-H gel, contributed to a dense microstructure.

scholarly journals Synergistic Excitation Mechanism of CaO-SiO2-Al2O3-SO3 Quaternary Active Cementitious System

2021 ◽  
Vol 8 ◽  
Author(s):  
Fusheng Niu ◽  
Yukun An ◽  
Jinxia Zhang ◽  
Wen Chen ◽  
Shengtao He
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Test Block ◽  
Hydration Reaction ◽  
Alkaline Environment ◽  
Granulated Blast Furnace Slag ◽  
Cementitious System ◽  
Furnace Slag

In this study, the influence of steel slag (SS) content on the strength of the cementitious materials was investigated. The quaternary active cementitious material (CaO-SiO2-Al2O3-SO3) was prepared using various proportions of steel slag (SS), granulated blast furnace slag (BFS), and desulfurized gypsum (DG). The mechanism of synergistic excitation hydration of the cementitious materials was examined using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). The strength of the mortar test block was initially increased and decreased later with the increase of the SS content. Mortar test block with 20% steel slag, 65% granulated blast furnace slag, and 15% desulfurized gypsum with 0.35 water-binder ratio showed the highest compressive strength of 57.3 MPa on 28 days. The free calcium oxide (f-CaO) in the SS reacted with water and produced calcium hydroxide (Ca(OH)2) which created an alkaline environment. Under the alkaline environment, the alkali-activated reaction occurred with BFS. In the early stage of hydration reaction, calcium silicate hydrate (C-S-H) gel and fibrous hydration product ettringite (AFt) crystals were formed, which provided early strength to the cementitious materials. As the hydration reaction progressed, the interlocked growth of C-S-H gel and AFt crystals continued and promoted the increase of the strength of the cementitious system.

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