Regression Analysis of the Standard Proctor Test on Chemically Treated Tropical Soil

Abstract

This study investigated the regression analysis of tropical soil (TS) stabilised with calcium chloride salt (CCS) using the Standard Proctor Method (SPM) to assess its suitability as a pavement construction material. Laboratory tests, including Atterberg limits (liquid limit, plastic limit, and plasticity index) and compaction parameters (maximum dry density, MDD; optimum moisture content, OMC), were conducted on both natural and stabilised soils in accordance with British Standard Light specifications. CCS was applied at concentrations ranging from 4% to 16%. Results were evaluated using analysis of variance (ANOVA) and regression analysis. Findings indicated that increasing CCS content increased the coarseness of the lateritic soil. MDD initially decreased from 1.63 Mg/m³ (untreated) to 1.45 Mg/m³ at 4% CCS, then increased to 1.97 Mg/m³ at 16% CCS, while OMC rose from 19.47% at 4% CCS and declined progressively at higher CCS. Regression analyses confirmed significant differences across most test parameters, except for the plasticity index, which showed no variation. High coefficient values were recorded across treatments. The study concludes that CCS effectively improves the engineering properties of tropical soils and recommends close monitoring of CCS content and liquid limit parameters during pavement design for low-traffic road applications.

Keywords

• Analysis of variance
• Calcium chloride salt
• Lateritic soil
• Regression analysis
• Standard proctor

Supporting Institution

The contributions of the laboratory attendants and system analysts in the Department of Civil Engineering are acknowledged.

Ethical Statement

The author(s) of this article declare that the materials and methods used in this study do not require approval from an ethics committee and/or special legal permission.

Kimyasal Olarak İşlem Görmüş Tropikal Zeminde Standart Proktor Deneyinin Regresyon Analizi

Abstract

Bu çalışma, Standart Proktor Yöntemi (SPM) kullanılarak kalsiyum klorür tuzu (CCS) ile stabilize edilmiş tropikal zeminin (TS) regresyon analizini incelemiş ve bu zeminin yol üstyapısı inşaat malzemesi olarak uygunluğunu değerlendirmeyi amaçlamıştır. Doğal ve stabilize edilmiş zeminler üzerinde, Atterberg limitleri [likit limit, plastik limit ve plastisite indeksi] ile kompaksiyon parametrelerini [maksimum kuru yoğunluk (MDD) ve optimum su muhtevası (OMC)] içeren laboratuvar deneyleri, British Standard Light şartlarına uygun olarak gerçekleştirilmiştir. CCS, %4 ile %16 arasında değişen oranlarda uygulanmıştır. Elde edilen sonuçlar varyans analizi (ANOVA) ve regresyon analizi kullanılarak değerlendirilmiştir. Bulgular, CCS içeriğinin artmasıyla lateritik zeminin daha iri taneli bir yapı kazandığını göstermiştir. MDD değeri, işlem görmemiş zeminde 1,63 Mg/m³ iken %4 CCS ilavesinde başlangıçta 1,45 Mg/m³’e düşmüş, ardından %16 CCS oranında 1,97 Mg/m³’e yükselmiştir. OMC ise %4 CCS ilavesinde %19,47’ye yükselmiş, daha yüksek CCS oranlarında ise kademeli olarak azalmıştır. Regresyon analizleri, herhangi bir değişim göstermeyen plastisite indeksi dışında, test parametrelerinin çoğunda anlamlı farklılıklar bulunduğunu doğrulamıştır. Uygulamalar genelinde yüksek katsayı değerleri elde edilmiştir. Çalışma sonucunda, CCS’nin tropikal zeminlerin mühendislik özelliklerini etkili bir şekilde iyileştirdiği sonucuna varılmış ve düşük trafik hacmine sahip yol uygulamalarında üstyapı tasarımı sırasında CCS içeriği ile likit limit parametrelerinin yakından izlenmesi önerilmiştir.

Keywords

• Varyans analizi
• Kalsiyum klorür tuzu
• Lateritik toprak
• Regresyon analizi
• Standart Proktor

Supporting Institution

İnşaat Mühendisliği Bölümündeki laboratuvar görevlileri ve sistem analistlerinin katkıları için teşekkür edilmektedir.

Ethical Statement

Bu makalenin yazar(lar)ı, çalışmada kullanılan materyal ve yöntemlerin etik kurul onayı ve/veya özel yasal izin gerektirmediğini beyan eder(ler).

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