scholarly journals The influence of OPC and PPC on compressive strength of ALWA concrete

2018 ◽  
Vol 195 ◽  
pp. 01021
Author(s):  
Fedya Diajeng Aryani ◽  
Tavio ◽  
I Gusti Putu Raka ◽  
Puryanto

Lightweight concrete is one of the options used in construction in lieu of the traditional normal-weight concrete. Due to its lightweight, it provides lighter structural members and thus, it reduces the total weight of the structures. The reduction in weight resulting in the reduction of the seismic forces since its density is less than 1840 kg/m3. Among all of the concrete constituents, coarse aggregate takes the highest portion of the concrete composition. To produce the lightweight characteristics, it requires innovation on the coarse aggregate to come up with low density of concrete. One possible way is to introduce the use of the artificial lightweight aggregate (ALWA). This study proposes the use of polystyrene as the main ingredient to form the ALWA. The ALWA concrete in the study also used two types of Portland cements, i.e. OPC and PPC. The ALWA introduced in the concrete comprises various percentages, namely 0%, 15%, 50%, and 100% replacement to the coarse aggregate by volume. From the results of the study, it can be found that the compressive strength and the modulus of elasticity of concrete decreased with the increase of the percentage of the ALWA used to replace the natural coarse aggregate.

2010 ◽  
Vol 3 (2) ◽  
pp. 195-204 ◽  
Author(s):  
W.G Moravia ◽  
A. G. Gumieri ◽  
W. L. Vasconcelos

Nowadays lightweight concrete is used on a large scale for structural purposes and to reduce the self-weight of structures. Specific grav- ity, compressive strength, strength/weight ratio and modulus of elasticity are important factors in the mechanical behavior of structures. This work studies these properties in lightweight aggregate concrete (LWAC) and normal-weight concrete (NWC), comparing them. Spe- cific gravity was evaluated in the fresh and hardened states. Four mixture proportions were adopted to evaluate compressive strength. For each proposed mixture proportion of the two concretes, cylindrical specimens were molded and tested at ages of 3, 7 and 28 days. The modulus of elasticity of the NWC and LWAC was analyzed by static, dynamic and empirical methods. The results show a larger strength/ weight ratio for LWAC, although this concrete presented lower compressive strength.


Author(s):  
Christopher Collins ◽  
Saman Hedjazi

In the present study, a non-destructive testing method was utilized to assess the mechanical properties of lightweight and normal-weight concrete specimens. The experiment program consisted of more than a hundred concrete specimens with the unit weight ranging from around 850 to 2250 kg/m3. Compressive strength tests were performed at the age of seven and twenty eight days. Ultrasonic Pulse Velocity (UPV) was the NDT that was implemented in this study to investigate the significance of the correlation between UPV and compressive strength of lightweight concrete specimens. Water to cement ratio (w/c), mix designs, aggregate volume, and the amount of normal weight coarse and fine aggregates replaced with lightweight aggregate, are the variables in this work. The lightweight aggregate used in this study, Poraver®, is a product of recycled glass materials. Furthermore, the validity of the current prediction methods in the literature was investigated including comparison between this study and an available expression in the literature on similar materials, for calculation of mechanical properties of lightweight concrete based on pulse velocity. It was observed that the recently developed empirical equation would better predict the compressive strength of lightweight concrete specimens in terms of the pulse velocity.


2012 ◽  
Vol 626 ◽  
pp. 344-349 ◽  
Author(s):  
Maryam Mortazavi ◽  
Mojtaba Majlessi

The purpose of this paper is to evaluate the effect of silica fume on compressive strength of structural lightweight concrete, containing saturated LECA (Light Expanded Clay Aggregate) as lightweight aggregate (LWA). In experimental phase of study 120 cubic specimens (10*10*10) were made and cured. For every mix design, different cement percentages were replaced with silica fume, containing same amount of saturated LECA. The mixes incorporate 0%, 5%, 10%, 15%, 20%, 25% silica fume. Constant level of Water/Cement ratio (0.37) was considered. For each mix design 20 specimens were prepared and cured for 7, 14, 28, 42 days in standard 20 C water. Also 20 specimens with the same mix design of 0% silica fume as normal weight concrete were prepared and cured to compare the results. For these specimens LECA were replaced with same volume and size of sand. The testing results showed; increasing silica fume causes considerable increase in compressive strength. The rate of strength gain slows down at high percentage of silica fume. Also silica fume leads concrete to get higher initial compressive strength at certain time compared with normal weight concrete.


Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3050 ◽  
Author(s):  
Khan ◽  
Usman ◽  
Rizwan ◽  
Hanif

This paper assesses the mechanical and structural behavior of self-consolidating lightweight concrete (SCLWC) incorporating bloated shale aggregate (BSA). BSA was manufactured by expanding shale pellets of varying sizes by heating them up to a temperature of 1200 °C using natural gas as fuel in the rotary kiln. Fly ash (FA) and limestone powder (LSP) were used as supplementary cementing materials (10% replacement of cement, each for LSP and FA) for improved properties of the resulting concrete. The main parameters studied in this experimental study were compressive strength, elastic modulus, and microstructure. The fresh-state properties (Slump flow, V-funnel, J-Ring, and L-box) showed adequate rheological behavior of SCLWC in comparison with self-consolidating normal weight concrete (SCNWC). There was meager (2%–4%) compressive strength reduction of SCLWC. Lightweight aggregate tended to shift concrete behavior from ductile to brittle, causing reduced strain capacity and flexural toughness. FA and LSP addition significantly improved the strength and microstructure at all ages. The study is encouraging for the structural use of lightweight concrete, which could reduce the overall construction cost.


2018 ◽  
Vol 4 (9) ◽  
pp. 2011 ◽  
Author(s):  
Meity Wulandari ◽  
Tavio Tavio ◽  
I G. P. Raka ◽  
Puryanto Puryanto

In the last decade, there have been many innovations developed to replace the aggregate as material for concrete, particularly the coarse aggregate using the artificial lightweight aggregates a.k.a. ALWA. In the study, the main ingredient used to develop the artificial lightweight aggregates is the styrofoam. Styrofoam has a lightweight characteristic so that it can reduce the density of the concrete. If the density of the concrete can be lighter than the normal-weight concrete then the overall weight of the structure of a building will also be lighter. Thus, the shear force due to the earthquake will also be smaller so that the safety of the building becomes better. The styrofoam used was dissolved with the acetone solution and formed into granules in which the size resembled the coarse aggregate size of about 10 to 20 mm. The styrofoam which has been formed then dried up so that the texture becomes hard. In addition, steel fiber was also used as an added ingredient in concrete mixtures so that the concrete was highly resistant against cracking and was expected to increase the compressive strength of the concrete. ALWA compositions used to replace coarse aggregates were 0%, 15%, 50%, and 100%. While the composition of steel fiber used was 0%, 0.75%, and 1.5% of the total volume of the cylinder. The type of steel fiber used was hooked-end steel fiber with the diameter and the length of 0.8 mm and 60 mm, respectively. The results showed that the concrete with 15% styrofoam ALWA and 1.5% of steel fiber were able to produce optimum compressive strength by 28.5 MPa and the modulus of elasticity by 23,495 MPa. In addition, the use of Styrofoam ALWA as a substitution to the coarse aggregate can reduce the density of concrete as much as 5 to 35%.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1187 ◽  
Author(s):  
Lucyna Domagała

The aim of this paper is to discuss the unrecognized problem of the scale effect in compressive strength tests determined for cored specimens of lightweight aggregate concrete (LWAC) against the background of available data on the effect for normal-weight concrete (NWAC). The scale effect was analyzed taking into consideration the influence of slenderness (λ = 1.0, 1.5, 2.0) and diameter (d = 80, 100, 125, and 150 mm) of cored specimens, as well as the type of lightweight aggregate (expanded clay and sintered fly ash) and the type of cement matrix (w/c = 0.55 and 0.37). The analysis of the results for four lightweight aggregate concretes revealed no scale effect in compressive strength tests determined on cored specimens. Neither the slenderness, nor the core diameter seemed to affect the strength results. This fact should be explained by the considerably better structural homogeneity of the tested lightweight concretes in comparison to normal-weight ones. Nevertheless, there were clear differences between the results obtained on molded and cored specimens of the same shape and size.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Teewara Suwan ◽  
Pitiwat Wattanachai

Global warming is a vital issue addressed to every sector worldwide, including the construction industry. To achieve the concept of green technology, many attempts have been carried out to develop low-carbon footprint products. In the construction sector, Autoclaved Aerated Concrete (AAC) has become more popular and been manufactured to meet the construction demand. However, errors from manufacturing process accounted for approximately 3 to 5% of the AAC production. The development of AAC waste as lightweight aggregate in concrete is one of the potential approaches which was extendedly studied in this paper. The results showed that the compressive strength of AAC-LWA concrete was decreased with an increase in volume and coarse size. The optimum mix proportion was the AAC aggregate size of 1/2′′ to 3/8′′ with 20 to 40% replacement to normal weight aggregate. Internal curing by AAC-LWA was also observed and found to provide sufficient water inside the specimens, leading to an achievement in higher compressive strength. The main goal of this study is not only utilising unwanted wastes from industry (recycling of waste materials) but also building up a new knowledge of using AAC-LWA as an internal curing agent as well as the production of value-added lightweight concrete products.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Mehdi Maghfouri ◽  
Payam Shafigh ◽  
Muhammad Aslam

Oil palm shell (OPS) is a biosolid waste in palm oil industry in the tropical countries which could be used as aggregate in concrete mixture. Since 1984, OPS has been experimented as natural lightweight aggregate in research studies to produce lightweight concrete (LWC). Medium and high-strength LWCs using OPS as coarse aggregate were successfully produced. However, higher drying shrinkage and lower mechanical properties for concretes containing higher volume of OPS are reported in previous studies. Therefore, OPS is not fit to be used as full coarse aggregate in concrete mixture and therefore, there should be an optimum OPS content in concrete. In this study, in a normal-weight concrete, normal coarse aggregate was replaced with OPS from zero to 100% with an interval of 20%. Tests such as slump, density, compressive strength in different curing conditions, splitting tensile strength, initial and final water absorptions, and drying shrinkage of cured and uncured specimens were conducted to find out optimum OPS content in concrete. From the test results, it could be summarized that OPS content should not exceed 60% of total volume of coarse aggregate.


2010 ◽  
Vol 168-170 ◽  
pp. 2235-2240
Author(s):  
How Ji Chen ◽  
Wen Po Tsai ◽  
Ming Der Yang

A kind of lightweight aggregate (LWA) has been successfully developed in Taiwan, which was made by expanding under heat fine sediments dredged from the Shihmen Reservoir. In this study the performances of concrete made from the aforementioned LWA were tested and compared with those of the companion normal weight concrete (NC). The test results show that the so produced lightweight concrete (LWAC) exhibited a comparable time-dependent properties (i.e., compressive strength, elastic modulus, drying shrinkage, and creep) as compared with those of the companion NC. Based on the results, it can be concluded that the use of prewetted LWAs and the incorporation of pozzolan materials can effectively control the drying shrinkage of LWAC. The specific creep of the LC mixture was obviously higher than that of the NC mixture at the same curing time.


2010 ◽  
Vol 150-151 ◽  
pp. 1588-1594
Author(s):  
Chao Wei Tang ◽  
Kuo Haung Fan ◽  
Wen Po Tsai ◽  
How Ji Chen

In the paper the properties of concrete masonry unit (CMU) made from sedimentary lightweight aggregate (LWA) were investigated. The main variables include water to cementitious material ratio (W/CM), filling ratio of paste or mortar in voids between coarse aggregate particles (Fv), filling ratio of sand in mortar (Fm), and cement replacement level by slag (Sc). Test results of representative CMU specimens show that unit weight ranged from 1585 to 1743 kg/m3, which was 30-25% lower than that for a normal weight CMU (2300 kg/m3); compressive strengths ranged from 8.4 to 18.7 MPa; water absorption was found to vary between 0.05 to 0.13 g/cm3; and thermal conductivity ranged from 0.27 to 0.41 W/mK. The research findings demonstrate that the use of sedimentary LWA as coarse aggregate in various concrete mixtures could produce high performance lightweight CMU, which comply with the requirements of Chinese National Standards (CNS) standards.


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