Previously · Chapter 1

Chapter 2 · Experimental Study

Stabilization of Silty Clay Using Cement.

An experimental program investigating how Al-Arish Type A Cement transforms the load–settlement behavior of soft silty clay collected from the banks of the Ismailia Canal, Egypt.

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Headline outcome

100%

Reduction in measured settlement after stabilization at 80 kg load.

10%

Cement content

15 cm

Treated layer

4.0 → 0

cm settlement

meet our team

Authored under academic supervision

A collaborative geotechnical investigation conducted by graduate researchers and laboratory engineers.

Eng. Mohamed Abdo

Eng. Nadia Ibrahim

Eng. Rokaya Mahmoud

Supervisor

Dr. Walid Hamdy El Kamash

Under Supervision

Eng.Menna Tullah Galal

Eng. Shimaa Hussein

Eng. Sahar Tarek

Introduction

This chapter presents the experimental program carried out to investigate the effectiveness of soil stabilization using Al-Arish Type A Cement in improving the engineering behavior of soft silty clay soil and reducing settlement under loading.

The experimental work consisted of two stages. The first stage was performed on untreated soft silty clay to determine its load–settlement behavior. The second stage was conducted after stabilizing the upper soil layer using cement treatment. The results obtained from both tests were compared to evaluate the effectiveness of the stabilization process.

Objectives of the Experimental Work

Four guiding questions framed the laboratory program from sample preparation through final load–settlement comparison.

Investigate settlement

Characterize the load–settlement behavior of untreated soft silty clay.

Evaluate stabilization

Quantify the effectiveness of cement treatment in reducing settlement.

Compare responses

Contrast pre- and post-treatment load–settlement performance.

Assess improvement

Measure gains in stiffness and bearing capacity after stabilization.

Materials Used

Three core materials defined the experimental matrix: soft silty clay as foundation soil, Al-Arish Type A cement as stabilizer, and water to achieve target consistency.

Foundation Soil

Soft Silty Clay

Dry soil mixed with water to obtain a soft consistency representative of weak silty clay deposits.

Soil Type: Soft Silty Clay
Dry Density: 1500 kg/m³
Moisture Content: 30%
Condition: Soft

Stabilizer

Al-Arish Type A Cement

The stabilizing material used to bind soil particles and develop strength through cement hydration.

Cement content

10%

of the dry weight of the treated soil layer

Selected for availability and proven performance in Egyptian geotechnical practice.

Water

Mixing Water

Water was added to the dry soil to achieve the required soft consistency throughout the experiments.

Assumed MC

30%

Used uniformly across both untreated and stabilized specimens.

Experimental Setup

A rigid steel box was fabricated to host every specimen, paired with a wooden loading plate to distribute applied loads uniformly across the soil surface.

Length

Width

Height

Total internal volume: 0.216 m³

Experimental test box 60×60×60 cm — Figure 2.1 — Test Box (60 × 60 × 60 cm)

Wooden loading plate — Figure 2.2 — Loading Plate

Experimental Program

The experimental work was divided into two main tests, sequenced to allow direct comparison on the same in-box soil column.

Untreated soil test

Soft silty clay placed at 55 cm thickness, loaded incrementally to 80 kg with settlement recorded.

Read the procedure

Cement-stabilized soil test

Upper 15 cm replaced with a 10% Al-Arish cement mixture, cured, and reloaded under the same sequence.

Read the procedure

Test No. 1

Untreated Soft Silty Clay

Soil Preparation

The soft silty clay was collected from the banks of the Ismailia Canal, Ismailia Governorate, Egypt, then transported to the laboratory to simulate the behavior of soft cohesive soils encountered in the field.

After visual inspection and cleaning of roots, stones, and organic debris, the soil was placed in a mechanical mixer to ensure uniform moisture distribution. Water was gradually added until a target moisture content of approximately 30% was reached.

The prepared mixture was transferred into the 60 × 60 × 60 cm test box and leveled to a uniform thickness of 55 cm, ready for loading and settlement measurements.

Silty clay soil collected from the Ismailia Canal — Figure 2.3 — Silty clay collected from the Ismailia Canal

Soil placement in mixer — Figure 2.4 / 2.5 — Soil placement and water addition

Quantity calculation

Soil & water for Test 1

Box filled to 55 cm thickness

Volume

V = L × B × H

V = 0.60 × 0.60 × 0.55

V = 0.198 m³

Dry soil weight

Wₛ = V × ρ

Wₛ = 0.198 × 1500

Wₛ = 297 kg

Water (MC = 30%)

W_w = 0.30 × Wₛ

W_w = 0.30 × 297

W_w = 89.1 kg ≈ 89 L

Dry Soil297 kg

Water89 L

Loading Procedure

After preparation, vertical loading was applied incrementally. Settlement readings were recorded after each load increment across three stages: 30 kg, 60 kg, and 80 kg.

1
30 kg
First loading stage
Fig. 2.10
2
60 kg
Second loading stage
Fig. 2.11
3
80 kg
Maximum loading stage
Fig. 2.12

Unloading Stage

After reaching maximum load, the load was removed gradually. The soil was allowed to recover elastically and the elastic settlement behavior was observed.

Placement of soil inside test box — Figure 2.8 — Placement of soil inside the test box

Loading weights — Figure 2.9 — Loading system

First loading stage 30 kg — Figure 2.10 — First loading stage (30 kg)

Second loading stage 60 kg — Figure 2.11 — Second loading stage (60 kg)

Maximum loading stage 80 kg — Figure 2.12 — Maximum loading stage (80 kg)

Load removal process — Figure 2.14 — Gradual load removal

Results of Untreated Soil

Applied Load (kg)	Settlement (cm)	Visualization
30	1.8
60	3.5
80	4.0

· Test No. 2

Cement Stabilized Soil

The upper 15 cm of the in-box soil was replaced with a stabilized mixture of soil, water, and 10% Al-Arish cement — cured before reloading.

2.7.1 Removal of Upper Layer

After Test 1, the upper 15 cm of soil was excavated, leaving 55 − 15 = 40 cm of original soft soil in the box.

2.7.2 Volume of Treated Layer

V = 0.60 × 0.60 × 0.15 = 0.054 m³

2.7.3 Dry Soil Weight

Wₛ = 0.054 × 1500 = 81 kg

2.7.4 Water Quantity (MC 30%)

W_w = 0.30 × 81 = 24.3 kg ≈ 24.3 L

2.7.5 Cement Quantity (10%)

Wc = 0.10 × 81 = 8.1 kg

Stabilized Mixture

Mixture Composition

Dry Soil81 kg

Water24.3 L

Al-Arish Cement8.1 kg

The soil, water and cement were thoroughly mixed until uniform, then placed back into the box to form a treated layer with a thickness of 15 cm.

Curing Period

The stabilized layer was left for curing and hardening before conducting the loading test. The curing period allowed cement hydration and strength development within the soil matrix.

Loading Procedure

After curing, the same loading sequence used in Test 1 was repeated. The settlement corresponding to each load increment was measured and recorded.

Results of Stabilized Soil

Load (kg)	Settlement (cm)
30	0.0	No settlement
60	0.0	No settlement
80	0.0	No settlement

Figure 2.15 — Stabilized soil under maximum load

Figure 2.17 — No visible settlement after stabilization

Comparison: Untreated vs Stabilized

Side-by-side load–settlement values reveal the magnitude of improvement delivered by cement stabilization across all three load increments.

Load (kg)	Before	Δ
30	1.8 cm	−100%
60	3.5 cm	−100%
80	4.0 cm	−100%

Max settlement before

4.0 cm

Max settlement after

0.0 cm

Figure 2.18

Load – Settlement Curve

Before and after stabilization · settlement increases downward

Discussion of Results

The untreated soft silty clay exhibited significant settlement under the applied loads, increasing gradually with load and reaching a maximum value of 4.0 cm under 80 kg.

After stabilization with Al-Arish Cement, the treated layer showed remarkable improvement. No measurable settlement was observed during loading, indicating a significant increase in soil stiffness and resistance to deformation.

Figure 2.18 confirms a substantial improvement in soil stiffness and load-carrying capacity due to the addition of Al-Arish Cement.

Conclusions

Five conclusions are drawn from the experimental investigation comparing untreated soft silty clay with cement-stabilized soil.

01
Untreated soft silty clay exhibits considerable settlement under external loading.
02
Cement stabilization significantly improves soil stiffness and strength.
03
The addition of 10% Al-Arish Cement effectively reduced settlement.
04
The treated soil exhibited a higher load-bearing capacity than the untreated soil.
05
Cement stabilization is an effective and economical technique for improving weak silty clay deposits and minimizing settlement problems.

Closing remark

A simple intervention. A measurable transformation.

Replacing the upper 15 cm of soft silty clay with a 10% Al-Arish cement mixture eliminated measurable settlement under loads up to 80 kg — demonstrating cement stabilization as a practical, economical solution for weak cohesive deposits.