scholarly journals THE RELATIONSHIPS BETWEEN COMPRESSIVE STRENGTH AND DENSITY OF POLYSTYRENE LIGHTWEIGHT CONCRETE AND THEIR COMPONENT RATIOS

2020 ◽  
pp. 1-11
Author(s):  
Mohammed Al-lami ◽  
Emad Al-saadi
Keyword(s):  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Experimental Program ◽  
Dry Density ◽  
Low Density ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Lining Material ◽  
Mathematical Relationships

The research deals with the properties of lightweight concrete, made from polystyrene, cement, sand and water, namely the compressive strength and density. This type of lightweight concrete is characterized by thermal insulation, low density and good compressive strength compared to other types of lightweight concrete. It is used as a lining material in inclination surfaces and in the production of unloaded building units and elements. The aim of this paper is to develop mathematical relationships between compressive strength and density of concrete and their mix proportions such as sand to cement ratio (S/C), water to cement ratio (W/C) and polystyrene to cement ratio (P/C). An intensive experimental program has been conducted. From the results of the tests, a mathematical relationships were suggested to find the proportions of components based the required compressive strength and dry density.

scholarly journals Experimental Investigation of the Production of Sustainable Lightweight Concrete

2020 ◽  
Vol 38 (11A) ◽  
pp. 1652-1665
Author(s):  
Mouhammed J. Lafta
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Dry Density ◽  
Normal Concrete ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Concrete Production ◽  
Concrete Mix

An experimental study on four types of coarse aggregate was conducted to produce lightweight concrete. These four types are namely; white limestone, red limestone, clay brick fragments, and pumice. Ordinary Portland cement was used for all examined mixes. Water to cement ratio (w/c) was modified according to the effect of coarse aggregate type on the workability of the resulted concrete for each mix. The reference concrete mix, which is normal concrete, water to cement ratio used was (0.5). The investigated characteristics for all concrete mixes were workability, compressive strength, dry density, absorption, and thermal conductivity. Results indicated that the aggregate type significantly affects most of the properties of lightweight concrete mixes such as workability, density, and thermal insulation for all tested types of concrete. All investigated specimens indicated improvement in terms of density, workability, and thermal conductivity when compared to the reference concrete mix. Yet, it was derived from the testing results that using pumice in lightweight concrete production is the optimum option among the other examined types. When compared to normal concrete, this type of lightweight concrete showed a 41% decrease in dry density, nearly 72.54% decrease in thermal conductivity, and about 12% increase in workability. However, it is vital to notice that due to the low compressive strength and the relatively high absorption capability for all the examined types of lightweight concrete, it is suggested to use these types of concrete for non-structural walls that are not subjected to or exposed to high humidity.

scholarly journals Novel Core-Shell Non-Sintered Lightweight Aggregate Concrete for Better Properties in Wallboard

2021 ◽  
Author(s):  
Chaoming PANG ◽  
Xinxin MENG ◽  
Chunpeng ZHANG ◽  
Jinlong PAN
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Dry Density ◽  
Core Shell ◽  
Aggregate Concrete ◽  
The Core

Abstract Shrinkage of foam concrete can easily cause cracking and thus makes it difficult for a manufacturer to maintain quality. The density of lightweight aggregate concrete is too high to meet specifications for lightweight and thermal insulation for wallboard. Two types of concrete with dry density in the range 1000–1200 kg/m3 for use in wallboard were designed and prepared using foam and lightweight aggregate. The properties of porous lightweight aggregate concrete with core-shell non-sintered lightweight aggregate were compared with sintered lightweight aggregate concrete along with several dimensions. The two aggregates were similar in particle size, density, and strength. The effects of each aggregate on the workability, compressive strength, dry shrinkage, and thermal conductivity of the lightweight concrete were analyzed and compared. Pore structures were determined by mercury intrusion porosimetry and X-ray computed tomography. Compressive strength ranged from 7.8 to 11.8 MPa, and thermal conductivity coefficients ranged from 0.193 to 0.219 W/m/K for both types of concrete. The results showed that the core-shell non-sintered lightweight aggregate bonded better with the paste matrix at the interface transition zone and had a better pore structure than the sintered lightweight aggregate concrete. Slump flow of the core-shell non-sintered lightweight aggregate concrete was about 20% greater than that of the sintered lightweight aggregate concrete, 28d compressive strength was about 10% greater, drying shrinkage was about 10% less, and thermal conductivity was less. Porous lightweight aggregate concrete using core-shell non-sintered lightweight aggregate performs well when used in wallboard because of its low density, high thermal insulation, and improved strength.

Lightweight Concrete Precast Panels for the Improvement of Thermal Insulation of Housing with Expanded Polystyrene Beads

2021 ◽  
Vol 1033 ◽  
pp. 163-171
Author(s):  
Alexandra Reto ◽  
Renzo Sanabria ◽  
José Rodriguez ◽  
Alexandra Hinostroza
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Linear Trend ◽  
Precast Concrete ◽  
Expanded Polystyrene ◽  
Dry Density ◽  
Conventional Concrete ◽  
Polystyrene Beads

The precast concrete elements in the construction of buildings are increasingly used due to their better quality control, constructive speed, reduction of the number of workers and less waste of resources compared to conventional construction; for wall applications, to these advantages, the design to ensure thermal comfort requires the improvement of the low thermal insulation of conventional concrete panels. The use of materials with lower thermal conductivity such as Expanded PolyStyrene Beads (EPSB) in lightweight concrete for the construction of precast panels in housing, contributes to improve thermal insulation and the saving operational energy during its operation phase, because the aggregate has a small size, low density and thermal conductivity; applied in higher volumes in concrete, reduces indoor heat loss in cold climates and indoor heat gain in warm climates in housing. The purpose of this research is to study the behavior of lightweight concrete with EPSB for 16%, 26% and 36% addition and evaluate the air-dry density, compressive strength, thermal conductivity, relationship between air-dry density with compressive strength and thermal conductivity. The results indicate that the higher the percentage of EPSB the air-dry density, compressive strength and thermal conductivity decrease; the relationships between air-dry density with compressive strength and thermal conductivity follow a linear trend and are similar.

scholarly journals CORRELATION BETWEEN PERMEABILITY AND POROSITY WITH OTHER PROPERTIES OF CONCRETE

2021 ◽  
pp. 1-9
Author(s):  
Mohammed Al-lami
Keyword(s):  
Compressive Strength ◽  
Test Results ◽  
Nitrogen Gas ◽  
Cement Ratio ◽  
Concrete Properties ◽  
Water To Cement Ratio ◽  
Helium Gas ◽  
Porosity And Permeability ◽  
The Subject ◽  
Mathematical Relationships

Most of concrete properties such as strength, permeability, density and absorption are significantly affected by the porosity of its internal microstructure. Many researchers studied the relationships between permeability, porosity and other properties of concrete, but in the author's opinion, the subject still needs more researching works. The purpose of this research is to investigate the possible correlations between concrete porosity and permeability with other properties such as compressive strength, absorption and density. Helium Gas Pores meter was used to measure porosity and Nitrogen Gas Permeate device was used to measure permeability. The investigated variables were the aggregate to cement ratio (A/C) and water to cement ratio (W/C). Based on regression analysis of test results, mathematical relationships between tested properties were suggested. The higher correlations were observed for mixes with constant water to cement ratio and variable aggregate to cement ratio.

scholarly journals Layered Grouting Technology Based on a Comprehensive Water-to-Cement Ratio for the Overlying Loess Stratum of Urban Shallow Tunnels

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Teng Yang ◽  
Jiaqi Zhang ◽  
Xiao Zhang ◽  
Qingsong Zhang ◽  
Zhanchao Yin
Keyword(s):  
Compressive Strength ◽  
Moisture Content ◽  
Strain Curve ◽  
Test System ◽  
Engineering Properties ◽  
Dry Density ◽  
Road Tunnel ◽  
Cement Ratio ◽  
Grouting Pressure ◽  
Water To Cement Ratio

Different from sand and clay, loess has special engineering properties; hence, existing soil grouting theories are not suitable for the disaster treatment of shallow loess tunnels. In this study, a fine grouting reinforcement test system was developed, and the Yuhan Road tunnel overlying loess was used as the injection medium. An orthogonal test based on slurry dry density, moisture content, water-to-cement ratio, and grouting pressure was conducted. Results revealed that the loess samples have high integrity after grouting, and the cohesion and compressive strength improved significantly. The stress-strain curve showed that the strengthened samples have greater ultimate and residual strengths than samples before grouting. Through a range analysis, it was determined that water-to-cement ratio and moisture content are the main factors affecting loess cohesion and compressive strength. Therefore, a comprehensive test of the water-to-cement ratio and moisture content as a single variable was conducted. It was found that their influence on loess cohesion and compressive strength is not a single linear relationship but a combined balance. To characterize the joint effect of water in loess and in slurry on reinforcement, the concept of a comprehensive water-to-cement ratio is proposed, and the cohesion and compressive strength curves with respect to this ratio were drawn. An optimal comprehensive water-to-cement ratio, which corresponds to the maximum cohesion or compressive strength, was found. Based on this ratio, we further propose a method to calculate the water-to-cement ratio of slurry and suitable grouting amount for the Yuhan Road tunnel reinforcement project, in which all solution parameters can be measured via field tests. In the project, a surface layered grouting scheme, based on the optimal comprehensive water-to-cement ratio, was designed. After grouting, loess strength was improved significantly, permeability was reduced greatly, and the overall reinforcement effect was suitable; these results provide a reference for similar projects.

Effects of Loading Percentage of Polyurethane in Lightweight Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 1082-1085 ◽  
Author(s):  
Kamarul Aini Mohd Sari ◽  
Sohif Mat ◽  
Khairiah Haji Badri ◽  
Muhammad Fauzi Mohd Zain
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Lightweight Concrete ◽  
Palm Kernel ◽  
Physical And Mechanical Properties ◽  
Concrete Mixture ◽  
Experimental Program ◽  
Polymer Concrete ◽  
Optimum Level ◽  
Methylene Diphenyl Diisocyanate

An experimental program was performed to obtain the density, compressive strength, and thermal conductivity of palm-based lightweight concrete. Palm-based polyurethane (PU) particles were used as lightweight aggregates in creating concrete systems. Concrete systems contain palm kernel oil-based polyol (PKO-p) reacted with 2,4-methylene diphenyl diisocyanate (MDI). In this study, polymer concrete was improved to achieve the optimum level of PU with the lowest possible density. The PU particles in the concrete mixture comprised of 1% to 5% w/w with density of less than 1800 kg/m3. The PU particles were 5 mm in size. The ratio of PKO-p to MDI was set at 1:1 and the loading of the concrete mixture was set at 3% w/w to produce lightweight concrete. The resulting concrete has excellent compressive strength (17.5 MPa) and thermal conductivity (0.24 W/mK). Results show that the PU particle dosage has the most significant effect on the physical and mechanical properties of concrete.

Chloride Ingress Control and Promotion of Internal Curing in Concrete Using Superabsorbent Polymer

2021 ◽  
Vol 888 ◽  
pp. 67-75
Author(s):  
Ariel Verzosa Melendres ◽  
Napoleon Solo Dela Cruz ◽  
Araceli Magsino Monsada ◽  
Rolan Pepito Vera Cruz
Keyword(s):  
Compressive Strength ◽  
Cementitious Materials ◽  
Internal Curing ◽  
Mix Design ◽  
Chloride Ingress ◽  
Superabsorbent Polymer ◽  
Cement Slurry ◽  
Chloride Permeability ◽  
Cement Ratio ◽  
Water To Cement Ratio

Chloride ingress into concrete from the surrounding environment can result in the corrosion of the embedded steel reinforcement and cause damage to the concrete. Superabsorbent polymer (SAP) with fine particle size was incorporated into the structure of concrete for controlling the chloride ingress and improving its compressive strength via promotion of internal curing. The SAP used in this study was evaluated for its absorbency property when exposed to cementitious environment such as aqueous solution of Ca (OH)2 and cement slurry. The results were compared to that in sodium chloride solution, the environment where absorbency of most of the SAP found in the market are well studied. Results showed that although SAP absorbency decreased with increasing concentration of Ca (OH)2 and cement, the results suggest that water containing cementitious materials are able to be absorbed by SAP. Chloride ingress into 28-day cured concrete specimens were determined using Rapid Chloride Penetration Test (RCPT) method employing 60V DC driving force. Concrete samples with size of 50 mm height x 100 mm diameter were prepared using a M25 mix design with 0.4 and 0.45 water to cement ratios and different percentages of SAP such as 0.05%, 0.1% and 0.15% with respect to cement mass. Results showed that concrete with 0.15% SAP gave the best result with 14% less chloride permeability than concrete with no SAP for a 0.4 water to cement ratio. Concrete samples for compressive strength tests with size of 200 mm height x 100 mm diameter were prepared using the same mix design and percentages of SAP and cured for 28 days. Results showed that the best results for compressive strength was found at 0.1% SAP at a 0.4 water to cement ratio which can be attributed to internal curing provided by SAP.

scholarly journals Use of Recycled Tyre Rubber in Non-structural Concrete

2018 ◽  
Vol 203 ◽  
pp. 06001
Author(s):  
Muhammad Bilal Waris ◽  
Hussain Najwani ◽  
Khalifa Al-Jabri ◽  
Abdullah Al-Saidy
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Structural Concrete ◽  
Cement Ratio ◽  
Mix Proportion ◽  
Water To Cement Ratio ◽  
Concrete Blocks

To manage tyre waste and conserve natural aggregate resource, this research investigates the use of waste tyre rubber as partial replacement of fine aggregates in non-structural concrete. The research used Taguchi method to study the influence of mix proportion, water-to-cement ratio and tyre rubber replacement percentage on concrete. Nine mixes were prepared with mix proportion of 1:2:4, 1:5:4 and 1:2.5:3; water-to-cement ratio of 0.25, 0.35 and 0.40 and rubber to fine aggregate replacement of 20%, 30% and 40%. Compressive strength and water absorption tests were carried out on 100 mm cubes. Compressive strength was directly proportional to the amount of coarse aggregate in the mix. Water-to-cement ratio increased the strength within the range used in the study. Strength was found to be more sensitive to the overall rubber content than the replacement ratio. Seven out of the nine mixes satisfied the minimum strength requirement for concrete blocks set by ASTM. Water absorption and density for all mixes satisfied the limits applicable for concrete blocks. The study indicates that mix proportions with fine to coarse aggregate ratio of less than 1.0 and w/c ratio around 0.40 can be used with tyre rubber replacements of up to 30 % to satisfy requirements for non-structural concrete.

Effects of Fly Ash Addition on Compressive Strength and Flexural Strength of Foamed Cement Composites

2013 ◽  
Vol 795 ◽  
pp. 664-668 ◽  
Author(s):  
Roshasmawi Abdul Wahab ◽  
Mohd Noor Mazlee ◽  
Shamsul Baharin Jamaludin ◽  
Khairul Nizar Ismail
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Cement Composites ◽  
Volume Percent ◽  
Foaming Agent ◽  
Cement Ratio ◽  
Water To Cement Ratio

In this study, the mixing of polystyrene (PS) beads and fly ash as a sand replacement material in foamed cement composites (FCC) has been investigated. Specifically, the mechanical properties such as compressive strength and flexural strength were measured. Different proportions of fly ash were added in cement composites to replace the sand proportion at 3 wt. %, 6 wt. %, 9 wt. % and 12 wt. % respectively. The water to cement ratio was fixed at 0.65 meanwhile ratios of PS beads used was 0.25 volume percent of samples as a foaming agent. All samples at different mixed were cured at 7 and 28 days respectively. Based on the results of compressive strength, it was found that the compressive strength was increased with the increasing addition of fly ash. Meanwhile, flexural strength was decreased with the increasing addition of fly ash up to 9 wt. %. The foamed cement composites with 12 wt. % of fly ash produced the highest strength of compressive strength meanwhile 3 wt. % of fly ash produced the highest strength of flexural strength.

scholarly journals Effects of Oil Palm Shell Coarse Aggregate Species on High Strength Lightweight Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ming Kun Yew ◽  
Hilmi Bin Mahmud ◽  
Bee Chin Ang ◽  
Ming Chian Yew
Keyword(s):  
Compressive Strength ◽  
Oil Palm ◽  
Lightweight Concrete ◽  
Good Condition ◽  
High Strength ◽  
Pulse Velocity ◽  
Dry Density ◽  
Coarse Aggregates ◽  
Palm Shell ◽  
Oil Palm Shell

The objective of this study was to investigate the effects of different species of oil palm shell (OPS) coarse aggregates on the properties of high strength lightweight concrete (HSLWC). Original and crushed OPS coarse aggregates of different species and age categories were investigated in this study. The research focused on two OPS species (duraandtenera), in which the coarse aggregates were taken from oil palm trees of the following age categories (3–5, 6–9, and 10–15 years old). The results showed that the workability and dry density of the oil palm shell concrete (OPSC) increase with an increase in age category of OPS species. The compressive strength of specimen CD3 increases significantly compared to specimen CT3 by 21.8%. The maximum achievable 28-day and 90-day compressive strength is 54 and 56 MPa, respectively, which is within the range for 10–15-year-old crushedduraOPS. The water absorption was determined to be within the range for good concrete for the different species of OPSC. In addition, the ultrasonic pulse velocity (UPV) results showed that the OPS HSLWC attain good condition at the age of 3 days.

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