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.

Laboratory Investigation on the Strength Characteristics of Cement-Treated Base

2014 ◽  
Vol 507 ◽  
pp. 353-360 ◽  
Author(s):  
Amiruddin Ismail ◽  
Mojtaba Shojaei Baghini ◽  
Mohamed Rehan Karim ◽  
Foad Shokri ◽  
Ramez A. Al-Mansob ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Moisture Content ◽  
Unconfined Compressive Strength ◽  
Resilient Modulus ◽  
Tension Test ◽  
Engineering Properties ◽  
Dry Density ◽  
Flexure Strength ◽  
Indirect Tension ◽  
Indirect Tension Test

Cement-Treated Base (CTB) is a non-conventional method used in road bases materials to improve its engineering properties due to the hardening of cement when moisture is present and extends the period of curing times. This study investigates the effects of cement additive on properties of base layer using laboratory mechanistic evaluation of stabilized soil mixtures. Laboratory tests conducted were Unconfined Compressive Strength (UCS), Indirect Tension test for Resilient Modulus (ITRM) and Flexure Strength (FS) tests. The results revealed that by adding Portland cement, the mechanical properties of the mixture have improved where the UCS is found to be an important quality indicator. In addition, the variables that influenced these tests, which are cement content, curing time, moisture content, and dry density, play important role to determine the performance of CTB. This paper presents the finding of a correlation conducted to analyse the influences of these variables using regression and ANOVA to establish significant models with the aim of predicting the strength base on mixture parameters. Keywords: Cement-Treated Base, Unconfined Compressive Strength, Indirect Tension test for Resilient Modulus, Flexure Strength, Moisture Content, Dry Density, Regression Analysis.

scholarly journals Soil Stabilization using Polypropylene Clamshell Food Containers

2021 ◽  
Vol 1200 (1) ◽  
pp. 012031
Author(s):  
N A C M Salwi ◽  
N Hamzah
Keyword(s):  
Compressive Strength ◽  
Moisture Content ◽  
Physical Properties ◽  
Soil Stabilization ◽  
Clayey Soil ◽  
Plastic Waste ◽  
Engineering Properties ◽  
Dry Density ◽  
Successful Implementation ◽  
Food Container

Abstract Soil stabilization is the method of improving the physical properties of soil, such as shear strength and bearing capacity of the soil, by using controlled compaction or the addition of admixtures to produce an improved soil material that has all the desired engineering properties. The new technique of soil stabilization uses plastic waste as an alternative material is of outmost crucial since plastic wastes are non-biodegradable and remain intact after being buried in soil for many years. The present study is focused on investigating the effectiveness of utilizing polypropylene clamshell food containers as soil stabilizers. The physical properties of the untreated clayey soil are determined by conducting moisture content, specific gravity, particle size distribution, and the Atterberg limit test. Also, the Standard Proctor compaction test, as well as the unconfined compressive strength test, are carried out to determine the compaction and strength parameters of the soil sample before and after reinforcing with different percentages of polypropylene clamshell food container strips such as 0.4%, 0.8%, and 1.2%. Findings from this study indicate that the addition of polypropylene clamshell food container strips in the clayey soil is capable of becoming a soil stabilizer agent as the optimum compressive strength of the soil was achieved with replacement of 0.8% of plastic strips, along with increasing the Optimum Moisture Content (OMC) while decreasing the Maximum Dry Density (MDD). Successful implementation of polypropylene plastic in soil stabilization can help minimize the volume of plastic waste in the environment, which then leads to developing a sustainable future by utilizing recyclable material as alternative sources in the geotechnical field.

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 Influence of Aggregate Gradation on the Engineering Properties of Lightweight Aggregate Concrete

2018 ◽  
Vol 8 (8) ◽  
pp. 1324 ◽  
Author(s):  
How-Ji Chen ◽  
Chung-Hao Wu
Keyword(s):  
Compressive Strength ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Engineering Properties ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Gradation ◽  
Aggregate Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Expanded Shale

Expanded shale lightweight aggregates, as the coarse aggregates, were used to produce lightweight aggregate concrete (LWAC) in this research. At the fixed water-cement ratio, paste quantity, and aggregate volume, the effects of various aggregate gradations on the engineering properties of LWAC were investigated. Comparisons to normal-weight concrete (NWC) made under the same conditions were carried out. From the experimental results, using normal weight aggregates that follow the specification requirements (standard gradation) obtained similar NWC compressive strength to that using uniform-sized aggregates. However, the compressive strength of LWAC made using small uniform-sized aggregates was superior to that made from standard-grade aggregates. This is especially conspicuous under the low water-cement ratio. Even though the workability was affected, this problem could be overcome with developed chemical additive technology. The durability properties of concrete were approximately equal. Therefore, it is suggested that the aggregate gradation requirement of LWAC should be distinct from that of NWC. In high strength LWAC proportioning, following the standard gradation suggested by American Society for Testing and Materials (ASTM) is optional.

scholarly journals Geotechnical Properties of Fresh and Degraded MSW in the Foothill of Shivalik Range Una, Himachal Pradesh

2019 ◽  
Vol 8 (2) ◽  
pp. 363-374 ◽  
Keyword(s):  
Moisture Content ◽  
Himachal Pradesh ◽  
Engineering Properties ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Overburden Pressure ◽  
Dump Site ◽  
Angle Of Internal Friction ◽  
Geotechnical Characteristics ◽  
Geotechnical Tests

The aim of the present study is to determine the physical and geotechnical characteristics of municipal solid waste (MSW) from an open dump site located in Una town, Himachal Pradesh (India) for the analysis of settlement and structural stability of landfill. Degraded waste was tested for different time intervals ranging from 6 months to 6 years. The physical characterization and the geotechnical tests were performed to determine the composition and the engineering properties of MSW respectively. The presence of moisture content in the fresh waste was 49.5±1.05% but for the degraded (or old) waste it varied between 39.8 to 51.6%. The specific gravity of fresh and old waste varied between 1.83±0.05 and 1.85 for 6 months old waste and 2.28 for 5-6 years old degraded waste respectively. The maximum dry density (MDD) was observed to be 4.28 kN/m2 for fresh waste at the optimum moisture content (OMC) of 78.1% and 4.47 kN/m3 for 6 months old waste and 6.25 kN/m3 for the degraded waste of 5-6 years at 80.2, 85.4% of OMC respectively. The hydraulic conductivity (k) of MSW was found to be decreasing with the degradation of MSW and the overburden pressure whereas the shear strength increased along with the degradation of the waste. The cohesion (c) and angle of internal friction (φ) increased respectively from 31.2 kPa(fresh) to 38 kPa(degraded) and 14° to 22° with the increase in waste degradation. The compression ratio of fresh waste was within the ranges of 0.19-0.29 and for degraded MSW it varied between 0.12 for 6 months old waste and 0.17 for 5-6 years old degraded waste respectively.

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 Engineering Properties of Foamed Concrete Containing Water Repellent

2018 ◽  
Vol 65 ◽  
pp. 02005 ◽  
Author(s):  
Yee Ling Lee ◽  
Chen Hoe Oh ◽  
Ming Han Lim ◽  
Foo Wei Lee
Keyword(s):  
Construction Industry ◽  
Vital Role ◽  
Engineering Properties ◽  
Water Repellent ◽  
Initial Surface ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Foamed Concrete ◽  
Optimum Water ◽  
Water Repellents

Concrete plays a vital role in the construction industry. Over the years, increasing demands from the construction industry had led to the birth of various types of concrete. Foamed concrete is one of the variations of lightweight concrete and yields a high percentage of porosity due to the internal presence of multiple air bubbles. Consequently, foamed concrete is prone to harmful substances’ penetration, which will disrupt its overall durability and the purpose of usage. Hence, water repellent is introduced into foamed concrete in this study and its effect on various engineering properties of foamed concrete will be investigated. The objectives of this study are to obtain optimum water-to-cement ratio for the 1200 kg/m3 foamed concrete and to study the impacts of water repellents on the fresh and engineering properties of foamed concrete. This study was separated into two main research phases. The first phase aimed at determining the optimum water-to-cement ratio for foamed concrete without the presence of water repellents, which was then determined as 0.48. The continuation of this research exhibited the utilization of the obtained optimum water-to-cement ratio from the first phase of the study to delve into the impact analysis of 0.2% and 0.4% calcium stearate (CS) on the fresh and engineering properties of foamed concrete. The incorporation of CS into foamed concrete had affected its mechanical properties in terms of compressive strength. However, it had played a vital role in improving the foamed concrete’s physical properties in terms of absorption, initial surface absorption and sorptivity. It was also found that the recommended dosage for CS incorporation was determined as 0.2% of cement weight as to prevent the adverse effects from overdosing of water repellents.

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.

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