IMPROVING WATER RESISTANCE OF MAGNESIUM OXYCHLORIDE CEMENT USING HYDROPHOBIC ADDITIVES

Öz

In this study, three water-repellent additives (silicon powder, calcium stearate, zinc stearate) were used to improve the water resistance of MOC, and their effects were examined through a three-stage experimental program. In the first stage, the optimal ratios for phase-5 formation were determined as RA = 13.21 mol/mol and RB = 16.57 mol/mol. Re-calcined MgO was then compared with original MgO, and re-calcined MgO showed higher performance with 11.77 MPa flexural strength and 70.6 MPa compressive strength. In the final stage, additives at 1%, 3%, and 5% were evaluated through capillary water absorption, 3–7–28-day water immersion, and softening coefficient tests. Results confirmed that RA = 13.21 and RB = 16.57 are optimal for phase-5 formation. In terms of impermeability, 1% zinc stearate provided the lowest capillary absorption (0.006 kg/m²·min⁰·⁵) and the highest softening coefficient (0.68). Overall, MOC systems produced with re-calcined MgO and 1% zinc stearate showed superior mechanical strength and water resistance.

Anahtar Kelimeler

• Capillary Water Absorption
• Compressive Strenght
• Magnesium Oxychloride Cement
• Softening Coefficient
• Water Resistance

HİDROFOBİK KATKI MADDELERİ KULLANILARAK MAGNEZYUM OKSİKLORÜR ÇİMENTOSUNUN SU DİRENCİNİN ARTIRILMASI

Öz

Bu çalışmada, MOC’un su dayanımını geliştirmek için üç su itici katkı (toz silikon, kalsiyum stearat, çinko stearat) kullanılmış ve etkileri üç aşamalı deneysel yöntemle araştırılmıştır. İlk aşamada faz 5 oluşumu için RA = 13.21 mol/mol ve RB = 16.57 mol/mol oranları belirlenmiştir. Ardından rekalsine MgO ile orijinal MgO karşılaştırılmış; rekalsine MgO’nun 11.77 MPa eğilme ve 70.6 MPa basınç dayanımıyla daha yüksek performans sağladığı görülmüştür. Son aşamada katkılar %1, %3 ve %5 oranlarında değerlendirilmiş; kapiler su emme, 3–7–28 gün suya daldırma ve yumuşama katsayıları ölçülmüştür. Bulgular, faz 5 için en uygun oranların RA = 13.21 ve RB = 16.57 olduğunu göstermiştir. Su geçirimsizlikte %1 çinko stearat en düşük kapiler su emme (0.006 kg/m²·dak⁰·⁵) ve en yüksek yumuşama katsayısını (0.68) sağlamıştır. Sonuçlar, rekalsine MgO ve %1 çinko stearat katkılı MOC’un mekanik ve su dayanımı açısından en başarılı sistem olduğunu göstermektedir.

Anahtar Kelimeler

• Basınç Dayanımı
• Kapiler Su Emme
• Magnezyum Oksiklorür Çimentosu
• Su Direnci
• Yumuşama Katsayısı

Kaynakça

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