Riku Arike Arto Hokkanen Patrik Nybergh Wäinö Raiskila 4.11 · Rak-43.3301 Repair Methods of...

Rak-43.3301 Repair Methods of Structures I (4 cr)

Autumn 2015 (Period I)

ShipShipShipShip----LabLabLabLab

Riku Arike

Arto Hokkanen

Patrik Nybergh

Wäinö Raiskila

4.11.2015



Table of content

1 Abstract 1.1 Abstract

1.2 Contributions

2 Introduction 2.1 Investigation problem

2.2 Aim and objectives of the investigation

2.3 Investigation methodology

2.4 Scope of the investigation

3 Location Details 3.1 Introduce the building and its site

3.2 Location

4 Site Investigation 4.1 Visual inspection Condition of the investigated case Non-Destructive Testing [NDT]

Destructive Testing [DT] Methods

4.2 Further research needed (Areas requiring attention)

4.3 Non-Destructive Testing [NDT]

4.3.1 Defects and non-destructive methods

4.3.1.1 Windows

4.3.1.2 Foundation wall

4.3.1.3 Concrete beams and columns

4.3.1.4 Brick-façade

4.4 Destructive Testing [DT] methods

4.4.1 Concrete structures

4.4.2 Mold inspection

5 Conclusion and Recommendations

6 Observations – Individual and Group



1 Abstract

1.1 Abstract

A preliminary survey of a building gives indications to the state of the building and its structures.

Often a simple visual investigation is enough to detect distresses that have occurred or may occur in

the future if left unattended.

This survey of the laboratory hall for Marine Technology at Aalto University is a preliminary

investigation of the condition of the buildings southern facade. The survey was done as a visual

inspection, no testing, whether destructive or non-destructive was done.

Distresses found during the survey include cracking in the concrete beams and footing, spalling of the

beams, longitudinal cracking and delamination of the brick-facade, erosion of the mortar joints in the

masonry, severe deterioration of the elastic joints in the wall and the poor condition of the window

benches and frames. There are also indications of moisture and possible mold in the structure.

In conclusion the building is in need of at least a more complete condition survey incorporating non-

destructive and possibly destructive testing. Based on this visual inspection of one facade alone the

building is in need of a thorough renovation. The assessment of moisture and mold as well as

surveying the condition of the load-bearing concrete structures are the most critical.

1.2 Contributions

Wäinö, 1. Abstract, 2. Introduction and 3. Location details

Patrik, 4.1 Visual inspection, 4.2 Condition of the investigated case

Riku & Arto 4.3 Non-Destructive Testing [NDT], 4.4 Destructive Testing [DT] and Laboratory Studies



2 Introduction

2.1 Investigation problem

Buildings and building materials deteriorate over time which may cause problems for the functionality

of the building. Deterioration occurs for many various reasons such as physical elements (climate

variation, material properties), exposure to chemical reactions, mechanical erosion or abrasion, faults

in design or in the construction of the building. The usage of the building can also cause deterioration

if the building is used for something it wasn't designed for.

Smaller defects such as minor cracking of concrete or eroded joints in masonry may easily be noticed

visually. Based on a simple visual inspection the state of the structure may be estimated. Smaller

defects may give hints of larger problems which, if not done anything about, may cause problems

later in the buildings service life and can be quite costly to repair after the damage has been done. It

is therefore important to construct regular surveys of buildings and structures.

2.2 Aim and objectives of the investigation

The goal of this investigation is to preliminary assess the condition of the building and identify factors

that may have led to this condition. Defects found will be detailed and the possible reasons for these

defects will be discussed. Based on this preliminary assessment recommendations for further tests

and evaluations will be given.

2.3 Investigation methodology

This investigation is a visual investigation. No non-destructive or destructive testing will be made due

to the time frame available to the members of our group. Distresses and deterioration of the different

parts of the facade such as the footing, load bearing concrete beams and masonry will be identified,

noted and photographed.

2.4 Scope of the investigation

The part of the building that is being assessed is the southern facade from the main entrance to the

western end of the building. Only the outside of the walls will be investigated.



Figure 2 Map of Otaniemi campus and location of the building

3 Location details

3.1 Building and site

The building in question is the laboratory of Marine Technology at Aalto University. The lab-building is

completed in 1968 and incorporates two pool halls and a working hall as well as some work-, office

and teaching spaces. The working-, office and teaching spaces are located at the southern façade. The

building has been renovated in 1986

3.2 Location details

Address: Tietotie 1, 02150 Espoo

Figure 1 The building for the laboratory of Marine Technology



4 Site investigation

4.1 Visual inspection

The visual inspection was done 23.09.2015 starting at 14.00 and ended about an hour later. The

inspection was started on the east side of the yard and moved along the facade inspecting all

structures in order.

The weather was clear and sunny while carrying out the inspection. According to the weather archive

meteoblue it had been rain free for roughly 24 hours prior to the inspection, relative humidity at 60 -

70% and the temperature 16C.

(source: https://www.meteoblue.com/en/weather/forecast/archive/otaniemi_finland_643522 , data

collected 29.09.2015)

The inspection was carried out without any equipment. It was carried out by four students making

sure to check the whole façade to decrease the possibility that any damage would be missed.

4.2 Condition of the investigated case

While carrying out the inspection damage could be found all around the façade. The damage was

clearly visible and directly affects the esthetics of the building façade. There was multiple instances of

the same type of damage. The type of damage seemed to repeat itself over the whole façade, where

similar structures had similar damage.

Delamination of concrete over the reinforcement could be found all over the entrance structures.

There where multiple instances of delamination. The amount of reinforcement that was visible

ranged from a couple of centimetres up to around 40 cm.

Figure 3 Delamination of the concrete over the reinforcement



The beam above the ground floor windows where badly damaged. The long beam that spans across a

majority of the façade had multiple types of damage all across the beam. However it seemed that the

frequency and extent of the damage seemed was bigger near the middle of the beam. Upon visual

inspection the beam seemed to be sagging, this however wasn’t confirmed with any equipment. The

type of damage to the beam included spalling delaminating, and cracking. In multiple cases the main

reinforcement bars where clearly visible. The cracks had different shapes and sizes and most likely

and are most probably caused by multiple different deterioration mechanisms.

Figure 4 Damage to the window beam.



The brick façade was also in a damaged state. There was multiple instances of brick spalling and

delamination. The plaster was either eroded or spalling around the damaged bricks. The spalling of

the bricks was mostly located near centreline of the brick façade or at the bricks in contact with the

window beam. Efflorescence was uncommon but could be found in a couple instances.

Further damage to both the brick façade and the plaster could be found at the ends of the window

beam. No or very little damage could be found on the beam at its end. The bricks where cracked.

Further wear and tear can be found on the window frames and the sheet metal under the windows.

The paint was chipped and there are wet stains on the sheeting. Further stains could also be found on

the foundation wall. The foundation wall also had lateral cracks distributed along the whole façade.

Figure 5 Spalling on the brick façade. Figure 6 Efflorescence of the bricks in on the facade

Figure 7 Condition of the beam at its end.



Figure 8 Spots on the foundation wall.

The material in the expansion joints was cracking and cracks could also be found in the structures that

surround the expansion joints.

At large the structure seemed dry. There were a few spots that looked wet or damp. They however

were too high up to confirm if they truly were wet or just dark stains. It is also noteworthy to mention

that the relative humidity was high and it had rained the previous day, so any moisture does not

necessary mean condensation or leakage in the actual structure and can be explained by being caused

by the outside weather.

Figure 9 Chipping of paint on the structures around the windows.

Figure 10 Condition of a expansion joint.



4.3 Non-Destructive Testing [NDT]

There are many different deterioration mechanisms in building facades and in building’s load-bearing

structures. Depending on the further purpose of the building some inspection methods are more

suitable or necessary than others. In our case we suppose that the building is in educational use so

health and safety issues are playing a crucial role.

The inspection of Ship Laboratory consists only of facade inspections which were done without any

special tools or equipment. Following conclusions and recommendations of testing methods about

deterioration mechanisms and damages inspected during the site visit are based only on visual

inspection.

4.3.1 Defects and non-destructive testing methods

4.3.1.1 Windows

Window benches and their sheet metals are not inclined. Therefore the outside water can end up

inside the structure from poorly made structural details. Paint cover of the sheeting metal is also

peeling even though the sheet metals are galvanized. It’s more like an esthetic problem. Wooden

frames of the windows are cracked and paint cover is very worn. There are no elastic sealants at joints

of window and sheet metal. Judging by the state of the window glasses, there might be some heat

flux. The moisture condense can be seen as “stains” in the venetian blinds (“säleikaihdin” in Finnish).

Raining water is a problem for the windows that are in poor shape.

Figure 11 Exterior window, window bench and its metal sheeting.



All the defects mentioned above can be spotted by a visual inspection. There is no need to carry on

with any further non-destructive testing methods considering the window structures and details.

Recommendation for the window structures is to update the area around the window with proper

structural detailing.

Samples from window and the sheeting paints can be taken to laboratory testing to find out if they

contain some harmful substances.

If energy efficiency is the main idea of the renovation, then thermal camera inspection is

recommended. Also in this case, heat fluxes and air-leakages should be examined. Air-leakages can be

tested also by tracer smoke –test. The air-tightness of the whole building can be measured with a

certain test method. In the test method a pressure difference is made between the inside and outside

of the building’s shell.

4.3.1.2 Foundation wall

Foundation wall is under moisture stress because there are no disconnecting crushed stone-lane

between the structure and soil. Since the aggregate of the soil is very fine, the moisture can move

capillary towards the foundation wall. Furthermore, the soil was not tilted away from the building.

The tilting of the soil should be more than 1:20 or 150mm during 3 meters distance from the wall. In

the visual inspection we couldn’t define if there was a water sealing layer on the wall or not. Some

algae growth was seen on the surface of the foundation wall. This suggests that the structure is moist.

Raining water splashes from the soil to the foundation. This is also an extra moisture stress for the

structure. All the moisture inside the exterior surface of the structure causes freezing/thawing

damage to the concrete if the concrete isn’t casted using protective pores. Moisture can move

capillary inside the concrete to the surrounding materials.

Figure 12 Grass is growing right next to the foundation wall



Vertical cracks were seen in the surface of the foundation wall. Cracks were approximately evenly

located along the wall. Crack width was so big that they don’t meet the requirements of calculated

and limited crack width (according to standards). Cracks contribute faster progress of CO2

penetration. In humid environment the corrosion of reinforcement bars happens also faster.

The crack width must be caused because of the normal temperature movement and blocked

shrinkage and/or the lack of aftercare of the cast-in-situ concrete and temperature gradient between

outer and inner layer of the cast-in-situ concrete right after casting. Most likely there isn’t any stress

in the reinforcement bars due to external loads so the cracks must be caused by the phenomena

mentioned above. A defect, caused by local erosion or possibly water segregation, on the foundations

wall’s surface was seen. Movement joints of the foundation wall were not filled with elastic sealant.

Therefore the exterior moisture can damage the structure. Movement joint were located

approximately in every 30 meters.

Soil issues can be spotted by a visual inspection and by checking old blueprints and plans of the

building. The moisture level of the concrete can be measured from the surface with a humidity

detector. Comparison is made between the measured values and limit values. Concrete cover

thickness of the reinforcement bars and the locations of the reinforcement bars should defined by

Figure 13 Lack of elastic sealant in the movement joint, local erosion on the surface and vertical cracks



using a specific concrete-cover-meter. After the thickness of concrete cover is defined, the level of

carbonation can be approximately calculated. Moreover, the carbonation level should be ensured by

using destructive method (see paragraph 4.4).

Crack widths are recommended to check more closely by measuring magnifier (digital or optical

device). Measuring magnifier works like a microscope magnifying the cracks with a certain scale to be

seen easier and estimated.

Galvapulse-testing is a non-destructive method in order to easily define the approximate ratio and

risk of corrosion in the reinforcement bars of foundation wall.

4.3.1.3 Concrete beams and columns

Concrete beams supporting the masonry-built façade are visually in poor condition. The beam is

assumed to be L-profile. The reinforcement bars were visible in many places due to the corrosion of

the reinforcement bars. Corrosion has caused local concrete sp. Thermal movement and shrinkage of

the concrete beam has cracked the joint between façade bricks and concrete beam. White limestone-

powder was seen in all of the façade-supporting beams. The aggregate of the concrete beams was

very fine which contributes the shrinkage even more. Minor changes could be seen in the line of the

façade considering the concrete beams. The reason might be in cast-in-situ mold or creep under the

bending stress of the beam.

Taking into account the age of the structure the concrete members of the building must have been

carbonated. All the cracks in surface of the members contribute the extent of carbonation. Because of

moisture and carbonation together, there are large cracks and spalled parts in the concrete

structures.



Corrosion of the reinforcement bars can be seen in the structure. The moisture level of the concrete

can be measured from the surface with a humidity detector. Concrete cover thickness of the

reinforcement bars and the locations of the reinforcement bars should defined by using a specific

concrete-cover-meter. After the thickness of concrete cover is defined, the level of carbonation can

be approximately calculated.

Moreover, the carbonation level should be ensured by using destructive method (see paragraph 4.4).

Also drilled concrete samples can be taken in order to define strength and texture of the concrete.

This is done by destructive methods.

Crack widths are recommended to check more closely by measuring magnifier (digital or optical

device). Measuring magnifier works like a microscope magnifying the cracks with a certain scale to be

Figure 14 Deterioration of window beams and movement caused by shrinkage and temperature variation



seen easier and estimated.

4.3.1.4 Brick facade

The moisture of the façade and its freezing and thawing has caused longitudinal cracks inside the

bricks and their surface has delaminated. Some of the ventilation gaps between the bottom bricks

were full of mortar. The expansion joints of the brick-façade seemed to be old and hardened. The

elasticity of the joints was not working. The joint material was removed from its base and cracked. In

addition, the thermal movement of the bricks has pushed/pumped the joint and it had become very

narrow (see figure 14).

Deterioration of brick-façade was visually inspected. Further investigation of the façade could be

checking the condition of bricks by hollow sound test (“kopo-kartoitus”). Hollow sound test shows the

areas where part of brick has delaminated from its base.

Movement joints between the brick-façade can contain harmful substances such as PCB or lead. Small

samples can be taken to further laboratory testing in order to define the toxicity of these materials.

Also the mortar between bricks can contain asbestos so it should be examined in laboratory.

Flat jack-testing method could be made masonry structures to determine properties such as

compressive strength and in-situ stresses of older structures.

Figure 15 Delamination of bricks due to freezing and thawing



4.4 Destructive testing methods

4.4.1 Concrete structures (foundation wall, columns, beams)

The destructive testing is based on what is presented earlier in the paragraph 4.3.1. These testing

methods are mostly suitable for concrete structures.

Considering the foundation wall, the soil next to the building can be dug open and inspected visually.

The repair method can suitable structural details and right soil material next to the wall. Also water-

proofing on the wall member should be added if there currently is none.

If the foundation wall already has some kind of water-proofing layer, it should be examined with

laboratory testing due to doubt of some toxic containts. Old water-proofing layers (bitumen) can have

for example some asbestos in it.

Samples from the concrete structures should be taken by diamond-drilling cylinder-like-parts out of

the wall. These samples should be packed with extra care to suitable plastic bags and the samples

should be numbered to ensure that they don’t mix up in the laboratory testing.

Phenolphtalein-test can be done right after the drilling or it can be made in the laboratory

environment. Carbonated area doesn’t colour pink when it reacts with the chemical. Carbonation

depth can be measured from the drilled samples.

From the drilled sample, few separate thin-section analyses should be done in order to see the

specific texture of the concrete. In the thin-section analysis things such as air-pores, quality of

concrete cement and cement paste, non-hydrated cement, quality of aggregate and additional

materials like fly ash, limestone and silica. From the thin section analysis the water-cement ratio can

be also estimated. From the amount and size of air-pores the resistance against frost can be

evaluated. In the thin-section perpendicular and parallel cracks are visible when inspecting the

sample.

In the thin-section analysis the relative amounts of each ingredient can be estimated. Also the

carbonation depth is seen in thin-sections.

Some of the drilled cylinder samples should be taken to tensile strength testing in the laboratory in

order to determine the tensile strength of concrete member. According to tested tensile strength, the

effect of freezing and thawing to the structure can be evaluated. Also the measured tensile strength

gives good idea of the compression strength of the concrete sample if the strength of concrete is not

already known. The tensile and compression strengths can be found in tables for example Eurocode



EN1992-1-1.

The moisture levels of the concrete structures in long-time period can be measured with sensors that

are drilled inside the structure core. The sensors gather data for months or even for years of the

variation of moisture levels in the structure.

4.4.2 Mold inspection

Based on the visual inspections, there might be some moisture in side of the masonry structure.

Samples for mold-testing should be taken from the insulation layer between the interior and exterior

shells. Taken should be tested for harmful micro-organisms in the laboratory.



5 Conclusions and recommendations

The structures overall are in quite bad condition. By visual inspection a large number of defects and

deterioration mechanisms that need more attention can be seen. Depending on what is the future

function of the building and what is wanted to be done, the extent of repair works can differ. The

structure needs full condition survey. The survey of concrete structures, mold and moisture are the

critical issues that must at least be examined further with destructive testing.

Based on our evaluation of the façade, which in itself is not highly critical to e.g. the load bearing

functionality of the building, we would rate it as “poor” a “4” on a scale from 1-6 according to the

Dutch standard for condition assessment of buildings. The façade is in very bad shape but this affects

the functionality of the building, not safety.

The most critical repairs we recommend are:

- Replacing the damaged bricks and repairing the damaged mortar joints in the masonry

- Repairing the window-beams and adding elastic joints between the masonry and beam ends

- Replacing the window frames and repainting and tilting of the metal sheeting of the window

benches

6 Observations – Individual and Group

Overall we find that we did a good job. Everyone did their part and there weren’t any disagreements.

The workload was the only thing we didn’t get right at the beginning. We split the workload according

to the table of contents estimating the amount of required work, it later turned out that the

distribution wasn’t even. After that we decided to redistribute the writing of report and finally

everyone did approximately the same amount of work.

Other minor misses that we could think of include some nondestructive tests could have been applied

in the survey and a few more group meetings would have been beneficial.

Riku Arike Arto Hokkanen Patrik Nybergh Wäinö Raiskila 4.11 · Rak-43.3301 Repair Methods of...

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