Influence of Polymer Types on the Mechanical Properties of Polymer-Modified Cement Mortars

Токарчук

et al. 2022

EEJET

The physical-mechanical influence and chemical effect of calcium formate, vinyl acetate/versatate, and vinyl-acrylate copolymer on the processes of solidification, hardening, and structure formation of the cement matrix were studied during the research reported here. The compositions of mixtures containing additives in the amount of 1, 3, and 5 wt % were investigated. Noteworthy is the water-holding nature of vinyl acetate/versatate and vinyl-acrylate copolymer. With the introduction of appropriate additives, an increase in working time of the mixtures is noted, which was manifested in prolonging the end time of solidification duration. Calcium formate reduced the end time of solidification duration with an increase in the content of the additive. During 28 days of hardening, a decrease in strength gain was observed with an increase in the content of the additive compared to control samples. At 1 wt % of the additive, the decline in strength on day 28 was 8.7 % for calcium formate, 13 % for versatate, and 15.5 % for vinyl-acrylate copolymer. For versatate and vinyl acrylate with the addition of 3 and 5 wt % in the mixture, the loss of strength is 23–25 % and 27–56.7 %, respectively. 5 wt % calcium formate admixture, compared to 3 wt %, on day 7 and day 28 of hardening has a higher strength index. This nature of the effect of additives is explained by the formation of polymer structures throughout the volume of the mixture with the introduction of versatate and copolymer vinyl acrylate, as well as their chemical interaction with the components of the cement binder during hydration in the formed alkaline medium. Calcium formate plays the role of both a filler and a hardening accelerator due to the introduction of an additional amount of calcium ions. The reported results can be used as a basis for continuing to study the effect of redispersed additives on the durability of cement articles, the development of new formulations for building mixtures, and their potential use in the production of concrete.

Section: Examined Materials and Equipment Used In Experimentsmentioning

confidence: 99%

Section: Examined Materials and Equipment Used In Experimentsmentioning

confidence: 99%

Section: Examined Materials and Equipment Used In Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Identifying the influence of redispersed polymers on cement matrix properties

Токарчук

et al. 2022

EEJET

Türk Doğa Ve Fen Dergisi

“…Bulgular, SBR ile modifiye edilen çözümlerin gelişmiş mekanik parametrelere, yani gelişmiş sızdırmazlığa ve donma etkisine karşı daha fazla dirence sahip olduğunu göstermiştir. SBR lateks içeren beton üzerinde birçok araştırma yapılmıştır [21][22][23]. Aşağıdaki paragrafta, SBR'nin çimentolu kompozitlerde kullanımına ilişkin bir literatür taraması sunulmaktadır.…”

Section: Introductionunclassified

Stiren-Bütadien Kauçuk Lateks Modifiyeli Harçların Erken Yaştaki Fiziksel ve Mekanik Özelliklerinin İncelenmesi

Mermerdaş

Alğın

Ekmen

et al. 2021

Portland çimentosu, harç ve beton yapımında yaygın olarak kullanılmaktadır. Ancak çimento harcı ve betonun gecikmiş priz süresi, düşük çekme dayanımı, yüksek kuruma büzülmesi ve düşük kimyasal direnç gibi bazı dezavantajları vardır. Polimerler bu dezavantajları ortadan kaldırmanın yanı sıra, betonun işlenebilirliğini ve geçirimsizliğini arttırmak amacıyla katkı maddesi olarak kullanılabilmektedirler. Bu çalışmada, Stiren-Bütadien Kauçuk lateksinin kütlece farklı ikame oranlarını (%0, %5, %10, %15 ve %20) içeren harçların erken yaştaki (14 gün) sertleştirilmiş özellikleri incelenmiştir. Taze harç için yayılma ve birim ağırlık ölçümleri yapılırken, sertleşmiş harç üzerinde birim ağırlık, basınç dayanımı, eğilme dayanımı, su emme ve kapiler su emme testleri yapılmıştır. Sonuç olarak harç karışımlarında lateks miktarı arttıkça dayanım değerlerinin azaldığı görülmüştür. Lateks kullanımına bağlı olarak eğilme dayanım değerlerinde düşüş gözlenirken, %10 oranında lateks kullanımı kontrol karışımına kıyasla numunelerin eğilme dayanımı değerlerinde %3 oranında küçük bir artış sağlamıştır. Taze ve sertleşmiş harç numunelerinin birim ağırlıkları kontrol numunesine göre artmıştır. Kullanılan lateks, harçların işlenebilirliği, su emme ve kılcal su emme değerleri üzerinde olumlu bir etkiye sahip olmuştur.

“…Styrene-Butadiene Rubber (SBR) latex having characteristics of high-polymer dispersion emulsion and capable of bonding with other materials, is extensively used material in engineering construction. Many types of research have been carried out on concrete incorporating SBR latex [13][14][15]. In the following paragraph, a brief literature review concerning the use of SBR in cementitious composites is provided.…”

Section: Introductionmentioning

confidence: 99%

Effect of Admixtures on Mechanical Properties of Cementitious Mortar

Shaukat

Khitab

et al. 2020

Civ Eng J

In the current study, the primary focus is to investigate the effect of Styrene Butadiene Rubber (SBR), silica fume and fly ash on compressive and flexure strengths of cementitious mortar. Three types of specimens are prepared; the first series comprises of control specimen; the second one consists of the mortar’s specimen modified with SBR and the third one consists of the mortar’s specimen modified with SBR in a combination of fly ash and silica fumes. Mortar samples are cast in the weight ratio of 1:2.75 (cement: sand). The SBR is added at a rate of 20% of the mass of cement. The water to cement ratio (W/C) is kept at 0.5 for control specimens and the quantity of mixing water in SBR-containing samples is reduced by the same amount as the SBR is added: The adjustment is meant to obtain same consistency for all the specimens. 20% fly ash and 2.5% silica fume are added to the mortar as replacement of cement. Compressive and flexure tests are carried out according to ASTM standards. Moreover, SEM is also performed on samples at the age of 28 days. Studies reveal that SBR and SCMs reduce the mechanical strength of the mortars. SEM and EDS studies show that SBR hinders the formation of albite, whereas silica content from silica fumes and fly ash converts CaCO3 to Wollastonite (a white loose powder), which is responsible for the reduction of mechanical strength. The study also confirms that the addition of SBR in place of water hinders the formation of primary and secondary hydration products. Doi: 10.28991/cej-2020-03091610 Full Text: PDF