The objective of the study design non-load bearing lightweight blocks which are lighter in weight than standard blocks using polystyrene beads and to determine the effects of lighter blocks on the structure in terms of cost and weight of the building. The project was carried out with the assistance from teachers and Costveyors (Pvt.) Ltd in which the lightweight blocks were prepared in progression of 0%, 20%, 40%, 60%, 80% substitution of coarse aggregate with polystyrene beads. Two samples sizes were selected for preparation, 4” x 8” x 12” and 6” x 8” x 12”. After the preparation, blocks were cured for 3, 7, 14, & 28 days. Weight of the blocks were determined and then tested for compression using CTM machine. Results in weight and strength of the blocks were obtained and reduction in block weight was achieved as 27%. To determine the effect of these blocks in building, first a commercial building was selected but after analyzing the building in load it was found that the building was not dominant in block masonry. So after, consultation with teachers and professional, the commercial building was converted into a residential apartment building by changing wall layout in the building only. The residential apartment building was then analyzed for concrete, reinforcement, block masonry and dead load using standard blocks. The building was again analyzed for dead load using lightweight blocks. At reduced loads and moments structural members of the building were redesigned and estimation of concrete & reinforcement was done. Total weight and cost estimation was done for both structures. It was found that weight and cost of the building was reduced by 15% and 10%. Major outputs of the project included 1) Conventional structure is expensive than lightweight. 2) Saving on materials, as structural members sizes reduced.

1. Effectof Lightweight Blocks OnHigh Rise ResidentialBuilding Weight &
Cost:A Case Study
BY
Syed Muhammad MeesumHussain Zaidi
Planning Engineer
TotalConstruction Pvt. Ltd
Meesum.nedian@gmail.com
Abstract
In Pakistan,conventionally the buildings are made in Reinforced Cement Concrete (RCC)resulting in being
designed as a heavier structure that is mostly unnecessary and costly. The main objective of this
investigation is to study the effect of EPS blocks on building structure with particular stress on saving in
overall cost and weight. To achieve the objective of the study, first lightweight blocks were prepared in two
sizes 4 inch by 8 inch by 12 inch and 6 inch by 8 inch by 12 inch, using Expanded Polystyrene Beads (EPS)
of size (3mm-5mm) in replacement with coarse aggregate of size (10mm-20mm) by volume at 0% (control
sample), 20%,40%, 60%,80% at 3,7,14 and 28 days of curing. Control sample waspreparedfor comparison
between blocks and after testing the EPS blocks, maximum reduction in the block weight was coming out
to be 28.7% at 80% replacement of coarse aggregate with polystyrene beads. EPS blocks were produced
suitable according to BS 1881 specifications. To investigate the effect of lightweight block on building, a
hypothetical real life apartment building of 28 stories was selected as a case study and first analyze using
standard blocks in different aspects i-e quantity estimation, reinforcement calculations, amount of blocks
determination in the building. Then the same building was analyzed using EPS blocks of 80% replacement,
14.8% reduction in the overall building weight has been observed when the contribution of block masonry
load in overall building was 45%. It was also observed after performing analysis on different type of
structures that lightweight blocks show accountable result in high rise building dominant in block masonry.
Keywords
Expanded polystyrene beads, lightweight blocks, coarse aggregate,hypothetical, reinforcement.
Background
In Pakistan, traditionally the buildings are made in Reinforced Cement Concrete (RCC) resulting in being
designed as a heavier structure that is mostly unnecessary and costly. One of its reasons is that the concrete
blocks are made heavier which increases the dead load of the structure and the risk associated with the
concrete structure (Nordberg, 1993). It has been found that the considerable amount of dead weight which
is contributed by the non-structural elements (such as non-load bearing walls) can be reduced if lighter
options are utilized (Babu and Tiong-Huan, 2006). For Building, there are many lightweight options
available in the market that can be used as replacement of the concrete blocks or used with concrete by
partial or full replacement of coarse aggregate to reduce the weight of concrete block by keeping the desired
strength (Babu, 2003). In which, Pumice stone and polystyrene are used to produce lightweight blocks
worldwide (Clarke, 2002). In the context of Karachi,pumice stone is not easily available, or if it is available
then it is highly expensive, in contrast with it polystyrene beads are easily available in mass at different
sizes at cheap cost. It is seen that EPS block can achieve greater compressive strength if small size
polystyrene beads are used in the concrete. Polystyrene beads are used in construction as permanent option
for making lightweight blocks. The polystyrene blocks are energy efficient and ensure optimal solution to
minimize the weight, not only for walls of building, but for whole structure (Short and Kinniburgh, 1978).
Considering these advantages, EPS blocks was used as the lightweight block to see maximum possible
reduction in the building.

2. Methodology
Methodology of the study includes:
1. The production of the EPS blocks
2. Building analysis
3. Case study-1
4. Case study-2
a. Traditional building analysis
b. Lightweight building analysis
1. The Production ofthe EPS Blocks
The method for making of blocks wasderived from the literature review and the field survey, which consists
of material estimation, sieving, mixing, molding, curing. For the production of the EPSblocks, a site within
the context of Karachi had been selected where all necessary equipment’s for the block making were
provided. Firstly, calculation for the number of blocks was done and afterward calculation of the material
used for the exercise was done in mass.
Description Quantities
Blocks prepared for exercise
Standard block (4"x8"x12") 12
EPS blocks (6"x8"x12") 48
Standard block (6"x8"x12") 12
EPS blocks (6"x8"x12") 48
Afterdetermining the number of blocks and quantity of material used, EPSblocks were made by the volume
replacement of the coarse aggregate with polystyrene beads in concrete, which result in making a block
lighter in weight as compared to the standard block. The steps for the preparation of EPS block is shown in
figure 1.
Figure 1: Procedure ofEPS block making
Material used for exercise Quantities
For 4"x8"x12" blocks 60 blocks
Cement 4 bags
sand 400 kg
coarse aggregate 460 kg
polystyrene beads 1.5 kg
For 6"x8"x12" 60 blocks
Cement 6 bags
sand 600 kg
coarse aggregate 690 kg
polystyrene beads 2.1 kg

3. The concrete mix ratio was used as 1:2:4. The water cement ratio varied from 40% to 55% according to the
percentage of polystyrene added in the mixture. Cement was used having strength of 6000 psi (28 days of
curing) available with 50 kg per bag and with volume of 1.25 ft3
. Fine aggregate of less than 9.5 mm was
used this value was found after literature review.
Coarse aggregate of 10mm-20mm wasused,asit wasfound from the literature review that coarse aggregate
contributes to 52-55% volume of the concrete and replacement of lightweight aggregate with bigger size of
the coarse aggregate may provide significant reduction in weight. The polystyrene beads of size 4mm-5mm
was used to produce lightweight block this value was also obtained from literature review.
Polystyrene is hydrophobic in nature and it float over the surface of the water,so to produce concrete with
polystyrene beads it is recommended to used admixture with polystyrene beads. The acrylic paint was used
as admixture and as 130 ml per 100 kg of cement (ACI 318).
Concrete for EPS blocks was made by the addition of all the materials separately in the concrete mixer,
which were weighted and then added in the machine. For the better result the mixer’s resolution was kept
slow and constant so that all the materials could mix together properly and a uniform mixture was obtained,
while the water and acrylic paint were added gradually observing the condition of material. After mixing,
this fresh concrete was compacted and molded in the block shape by using the block making machine.
Concrete was made separately for each size i.e. 4” x8”x12” and 6” x8” x12” and every replacement of
coarse aggregate i.e. 0% (control sample), 20%, 40%, 60% and 80%. These blocks were left for 24 hours
followed by the curing period. The temperature of weather was noted as 30 o
C.
After making of blocks, curing was done through ponding method because it is the most effective method
of curing and produces highest level of compressive strength. looking at this the curing was done by
following ASTM C140M for best results for standard and EPS blocks for 28 days respectively.
The blocks were testedaccording to ACI530. The testing wascarried through compressive testing machine
(CTM) at NED University of Engineering and Technology. The results of the testing of EPS and standard
blocks observed in observation section.
2. Building analysis
For the analysis of the building, first a real life commercial building of 28 stories was selected as a case
study but afterobtaining the load analysis result of the commercial building, it wasfound that the maximum
possible reduction in the building we can achieve using block of maximum weight reduction that we have,
was 2 % because total load of the block masonry contributed to the total load of the building was 5 % and
we have the block of twenty 7 % lightweight as compare to standard block.
If we use the block of 100% lightweight as compare to standard block so in that case, we can only achieve
maximum 5% reduction in the building load, while keeping all other parameters for load analysis constant
with both the traditional and lightweight blocks.
Designing the building at 2% reduced weight did not provide accountable results with appropriate cross-
section sizes and reinforcement. So using the area, column sizes, beam dimension and slab size of the
commercial building, just by changing the utility of the building for achievement of accountable results,
commercial building wasconverted into a hypothetical reallife apartmentbuilding keeping the number and
height of the story constant. For suitability, commercial building was named as case study 1 and the second
residential apartment building was named case study 2. Data from the commercial building has been used
for the residential building. Discussion starts with a brief summary of case study 1 and end with the
comprehensive discussion of case study 2.

4. 3. Case study-1: A Commercial Building
A 28 stories commercial building was first selected to study the effect of lightweight blocks in cost and
weight of the building, but afteranalysis it from different aspects,it wasfound that the commercial building
was not dominant in block masonry, and wall loads only contribute 5% to overall load of the building. By
using the EPS block of 80% replacement which is 27.8% lighter than the standard block, result obtained it
building load reduction was only 2%, which was not accountable, and this percent no significant change in
the cross-sections of the structural member seen which increased that cost of the structure because of the
high cost of lightweight blocks.
4. Case study-2: A Apartment Building
All the data that was used in case study-1, were remain same for the case study-2 except wall layout. This
building was a hypothetical 28 story building with a total height of 320 feet. Architectural drawings were
developed and the studied for the analysis. For the analysis, this case study disintegrates in two broad
sections.
First section named as traditional building analysis which includes concrete estimation of the building and
its cost, determination of the number of blocks in the building and its cost, reinforcement takeoff with its
cost and dead load analysis with standard blocks of 4 inches and 6 inches.
Second section, named aslightweight building analysis which includes deadload analysis using lightweight
blocks, designing of structural members after change in loads and moments on it, after redesigning
estimation of reinforcement and concrete in new member with their cost has been discussed. Model of the
building case study 2, prepared using CSI ETABS,shown in the figure below.
a) Traditional building analysis
To begin with analysis of conventional building,
calculation for concrete in the building was done
firstly.
Estimation of concrete for the conventional building
has been done using the provided details of the
building. For this purpose, BOQ has been prepared.
Using given drawings volumetric estimation, area
estimation and linear estimation was done. BOQ
prepared by following standards and methodologies
provided by Royal institute of chartered surveyors
(RICS). Results of estimation has been discussed in
the observation.
After determination of concrete in the building, to
proceed further next step was to estimate the quantity
of reinforcement in the building. For reinforcement
calculation bar bending schedule (BBS) has been
preparedusing British standardBS-8666 which covers
all design shapes and requirement of bending of bars
according to the provide conditions. The length and
number of the steel bars determined from structural
drawings using CAD software. Estimation has
observing in observation.
Subsequently, next step was to estimate the amount of blocks used in the building. Masonry calculation has
been done to calculate the number of blocks for the building. For this, the area of all the walls provided
Figure 2: Building 3D model

5. were taken out using plans and volume was calculated by multiplying it with the height of the wall. After
that number of blocks were found in the building by using the below formula:
Number of blocks =
Volume of blockmasonry
Volume of one block+ Thickness of plaster
After finding out the amount of blocks in the building, next step was to calculate the dead load of the
building with standard blocks. While calculating the load of the overall building, only dead load of building
was considered which comprises of slabs, beams, shear walls, masonry walls for the study.
The load analysis has beendone according to ACI318-05 with CSI ETABS software by designing building
using frame sections for beam & columns and area sections for slab & shear wall while other parameters
were set accordingly, in order to have load and moment reaction diagrams and calculations. Results of load
analysis observe in observation.
b) Lightweight building analysis
For the analysis of the lightweight building only the change in the density of blocks masonry has been
considered while keeping all the dimensions, data and assumptions constant. A lightweight building can be
produce if one of its member that may contribute to dead load of the building replaced with lightweight
member. For this research traditional building were analyzed using ETABS and the same procedure was
followed to analyze lightweight building. For the analysis of the lightweight building only the change in
the density of blocks masonry has been considered while keeping all the parameters constant. Note that
there is no change in the amount of blocks masonry used in the building, only the change is due to the
lightweight blocks in placement of standard blocks.
For lightweight building analysis, standard masonry blocks were replaced with lightweight EPS blocks of
80 percent replacement, while other structural members were remained same as well as the load assign to
them were also kept same as in traditional building analysis discussed previously. The load analysis results
with the lightweight blocks discussed in observation.
Using given drawings volumetric estimation, area estimation and linear estimation wasdone.BOQprepared
by following standards and methodologies provided by Royal institute of chartered surveyors (RICS). All
the heads of the description used for the conventional building, has also been used for the lightweight
building. The concrete estimation for lightweight building has beendone afterre-designing the beamscross
sections, columns dimensions, and raft foundation size. There was no change in the moment of slab before
and after the block change,so no change in the thickness of the slab which means no change in the quantity
of concrete in the slab. The BOQ for the lightweight building has been provided in observation.
For the reinforcement estimation of the lightweight building, reinforcement hasbeen determined for beams,
columns and foundation after the designing cross section of the members. Using bending moment elevation
diagrams CSI ETABS,maximum moment has been determined for re-designing of reinforcement and then
bar bending schedule has been prepared for lightweight building.
After obtaining results of both the buildings in different aspects,next step was to compare the weight of the
both blocks and weight of the both buildings, similarly cost of both the blocks and cost of both the building,
which has been discussed in the observation.
Observations
Firstly, results of the EPS blocks of maximum reduction in weight at different days of curing has been
observed and discussed. Results of strength has not been discussed all the results obtained fulfil the
requirement of minimum strength require for blocks to be used in walls which 600 psi and all values are
greater than 600 psi.

6. Table 1: Results at 3 days ofcuring Table 2: Results at 7 days ofcuring
Percentage
replacement
Average weight (kg)
4” 6”
block block
0% 13.7 18.7
20% 12.3 17.7
40% 12.4 16.7
60% 11.8 16.3
80% 10.5 14.9
Table 3 Results at 14 days ofcuring Table 4 Results at 28 days ofcuring
After observing the results, all the results of the weight of the EPS blocks are following a trend, with
increase in percentage of polystyrene beads used in replacement of coarse aggregate there is a gradual
decrease in the result can be seen, except weight of the block of 40% replacement at 3 days of curing. The
reason for this abnormality was that few of the blocks were not made with the uniform mix so honey
combing was observed in the blocks.
Traditional building results
After discussing the blocks result, traditional building analysis results has been discussed. Estimating of
concrete for different heads with cost provided in the table below.
Table 2: BOQ traditional building
S.no Description Unit Quantities Rate Cost (PKR)
1 Cleaning site Sq.m 3154 26 81,500
2 Excavation for foundation Cu.m 5806 365 2,109,200
3 Concrete foundation and superstructure Cu.m 31317 10500 328,265,700
4 No. of blocks Number 1452708 28 40,675,824
Afterwards quantities of reinforcement have been found out.
Percentage
replacement
Average weight (kg)
4” 6”
block block
0% 13.8 19.4
20% 13.1 17.7
40% 12.8 16.2
60% 11.6 15.5
80% 10.2 14.9
Percentage
replacement
Average weight (kg)
4” 6”
block block
0% 13.9 19.2
20% 13.1 17.8
40% 12.3 16.7
60% 11 15.6
80% 9.9 14.1
Percentage
replacement
Average weight (kg)
4” 6”
block block
0% 14.1 19.1
20% 13.2 17.9
40% 12.8 17.1
60% 11.2 16.2
80% 10.5 14.3

7. Table 3: Bar bending schedule outcomes
Cost of the steel was considered as Rs. 78,000/ton.
After reinforcement, number of blocks were determined and given in the following table.
Table 4: Number of blocks
No. ofblocks in building
Size Quantity
1. 4”x 8”x 12” 365472
2. 6”x 8”x 12” 1087236
After determining the number of blocks, dead load of the structure with standard blocks was found as
261405 kips.
Lightweight building results
For lightweight building results, structural analysis with lightweight blocks was performed first and overall
building result with EPS blocks was found as 219989 kips. As one can observe the difference in weight of
both the buildings. After determination of loads, building was redesign and outcomes of redesign in terms
of concrete and reinforcement which are given below.
Table 5: BOQ lightweight building
S.no Description Unit Quantities Rate Cost
1 Cleaning site Sq.m 3154 26 81,500
2 Excavation for foundation Cu.m 5806 365 2,109,200
3 Concrete in foundation and superstructure Cu.m 31317 10500 288,053,495
4 No. of blocks Number 1452708 32 46,486,656
Table 6: BBS lightweight building
Lightweight Building results
Sr.no Structural members Steel (tons) Cost
1 Raft foundation 244 19,032,000
2 Columns 601 46,878,000
3 Beams 357 27,846,000
4 Slabs 1546 120,588,000
5 Shear wall 159 12,402,000
6 Drop panel 18 1,404,000
Traditional Building result
Sr.no Structural members Steel (tons) Cost (Rs.)
1 Raft foundation 273 21,294,000
2 Columns 773 60,294,000
3 Beams 534 41,652,000
4 Slabs 1546 120,588,000
5 Shear wall 159 12,402,000
6 Drop panel 18 1,404,000
Total Reinforcement 3303 257,634,000

8. Comparison
After observing the results, now to conclude the study, comparison is made for weight and cost.
Weight comparison
First, building total weight comparison has been done and given in the table below.
Table 7: Building total weight comparison
Description Unit Load
Total Conventional building load Kips 261405.03
Total Lightweight building load Kips 219988.56
Afterward,blocks weight comparison was done and given the table below.
Table 8: Block weight comparison
Description
Conventional block
weight
EPS block weight (80% replacement of
polystyrene)
Size Weight (kg) Weight (kg)
4”x 8”x 12” 13.9 9.98
6”x 8”x 12” 19.1 14.2
Cost comparison
Similarly, cost comparison has been done for building and block and provided in the table below.
Table 9: Cost comparison
S.NO Elements Unit Traditional Building Light Weight Building
1 Concrete PKR 312,909,071 288,053,495
2 Reinforcement PKR 300,824,160 256,553,700
3 Blocks PKR 40,675,824 49,392,072
Total Amount PKR 628,759,051 567,797,837
SAVING PKR 60,961,214
Conclusion
Building weight totally depends on the block used in building. In this study two blocks are used for
comparison; standard & lightweight block.
As we know that in this building masonry wall contributes around 45% load of the building so if the weight
of the block decreases then totalload of the building can be decreases.
Table 10: Block weight Vs building load reduction
Block weight reduction % Building load reduction %
6.73 3.63
12.245 6.61

9. Structure comparison has been made between traditional & lightweight structure including all beams,
columns & non load bearing walls. There is a possible reduction in the sizes of these elements due to the
loss in loads of masonry walls. Lightweight structure is designed to introduce in the market as it is very
efficient for residential & commercial projects. It is reliable and costefficient asit is also having a insulation
property.
Lightweight blocks are used in this study which are slightly expensive than standard blocks as polystyrene
is used in it and is an expensive material. By using EPS(lightweight) blocks the sizes of columns and beams
can be reduced so it is saving the cost of overall structure and meeting the client’s need of a cost efficient
project. After comparison of overall cost, it is concluded that conventional structure is much costly than the
lightweight structure.
In general, lightweight construction is considered Weight to be favorable due to the savings in construction
materials. Less material means less embodied energy in the building. Conversely, heavier construction is
advantageous for the heating and cooling of the building. The operational energy is lower and thus a
relatively larger amount of embodied energy is required to compensate or even to level out. Sometimes
lightweight construction is more energy efficient than heavyweight construction. The energy efficiency of
a building in the use phase depends on many factors, climate, surrounding environment, location and
orientation, function of the building and capacity utilization to name just a few parameters.
As it is observed that lightweight means less weight so this structure is having reduced weight as compare
to traditional, along with it is having high strength which is collectively a strong point. There is 14.8%
reduction in weight of the building.
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19.66 10.6
27.495 14.83
35 18.88
45 24.29
60 33.78
75 42.37
80 44.781