Ground River Sand Research Articles

Influence of fly ash, cement and ground river sand on compressive strength and chloride penetration of mortar

The study deals with the strength and chloride resistance properties of mortar prepared by combining the Portland cement 43 grade, fly-ash and ground river sand. Fly ash and ground river sand were utilized to partially replace ordinary Portland cement type I. The replacement percentage of fly ash and ground river sand was varied from 0 to 40% and the mortar mixes were prepared. Fly ash and ground river sand was processed using ball mill and sieve with openings of 45 µm (sieve No. 325) was used to obtain 3% weight retained. The mortar samples were tested for their strength (compressive), penetration (Rapid chloride) and microstructural properties. The results indicated that the strength (compressive) increased and resistance to chloride penetration was excellent. According to SEM analysis, homogeneous and dense structure of the newly developed mortar was observed. Ground river sand addition, however, reduced strength and improved chloride resistance which indicated that it made changes to only packing structure. Strength and penetration resistance were enhanced and it was due to the pozzolanic effect of fine fly ash.

Evaluation of Strengths from Cement Hydration and Slag Reaction of Mortars Containing High Volume of Ground River Sand and GGBF Slag

This paper investigates the cement hydration, and the slag reaction contributes to the compressive strengths of mortars mixed with ground river sand (GRS) and ground‐granulated blast furnace (GGBF) slag with different particle sizes. GRS (inert material) and GGBF slag (reactive material) were ground separately until the median particle sizes of 32 ± 1, 18 ± 1, and 5 ± 1 micron and used to replace Portland cement (PC) in large amount (40–60%) by weight of the binder. The results showed that, at the early age, the compressive strength obtained from the cement hydration was higher than that obtained from the slag reaction. The results of compressive strength also indicated that the GGBF slag content and particle size play important roles in the slag reaction at the later ages, whereas cement hydration is more prominent at the early ages. Although the results could be expected from the use of GGBF slag to replace PC in mortar or concrete, this study had presented the values of the compressive strength along with ages and the finenesses of GGBF slag that contributed from cement hydration and from GGBF slag reaction.

Evaluation of Heat Evolution of Pastes Containing High Volume of Ground River Sand and Ground Granulated Blast Furnace Slag

This paper investigated the heat evolution of pastes containing inert and active materials with different particle sizes. Ground river sand was used as an inert material while ground granulated blast furnace (GGBF) slag was used as an active material. Ground river sand (GRS) and GGBF slag were ground to have the same particle size and were used separately as a replacement of Portland cement type I at rates of 50 – 70 % by weight of the binder. Heat evolution of pastes containing GRS and GGBF slag was measured using an isothermal conduction calorimeter up to 72 h. The results showed that GRS with different particle sizes had a slight effect on the heat evolution of pastes. GGBF slag with median particle size d50 of 4.4 µm and d50 of 17.8 µm had a small effect on the heat evolution of pastes during the first 24 h, and the pastes also had very low heat evolution for up to 72 h. At the same replacement rate of Portland cement, however, the heat evolution due to the slag reaction was slightly increased when the particle size of the GGBF slag was decreased. Finally, the higher is the cement replacement by GGBF slag, the higher is the slag reaction.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.13579

Strength and chloride resistance of the blended Portland cement mortar containing rice husk ash and ground river sand

In this paper, the strength and chloride penetration resistance of the blended Portland cement mortar containing rice husk ash (RHA) and ground river sand (GS) were studied. Portland cement type I (OPC) was partially replaced with RHA and GS and a blended of RHA and GS. The mortar mixtures were made with OPC containing 0–40 % of RHA and GS. RHA and GS with 3 % by weight retained on sieve No. 325 (opening 45 µm of sieve No. 325) were obtained using ball mill. The study includes compressive strength, rapid chloride penetration test, chloride ion diffusion coefficient and chloride penetration depth of mortars. Test results indicated that the use of RHA produced mortars with relatively high strength and excellent resistance to chloride penetration. However, the incorporation of GS reduced the strength and resistance to chloride penetration of mortars indicating that it asserted only the packing effect. The blend of equal portions of RHA and GS produced relatively high strength mortars with good resistance to chloride penetration which is probably due to the synergy of the pozzolanic effect of RHA and packing effect of GS.

Permeability and abrasion resistance of concretes containing high volume fine fly ash and palm oil fuel ash

In this paper, compressive strength, water permeability and abrasion resistance of concretes containing high volume fine fly ash (FFA) and fine ground palm oil fuel ash (GPA) were studied. Portland cement type I was replaced with FFA and GPA at dosages up to 70% by weight of binder. Ground river sand (GRS) was also used to replace Portland cement in order to indicate the level of filler effect. Results indicated that FFA was slightly more reactive than GPA. The replacement of 40-70% of FFA produced concretes with compressive strength, permeability and abrasion resistance comparable to those of normal concretes. The incorporation of GPA slightly reduced the performances of concretes as compared to those of FFA concretes. The reduction of Portland cement was partly compensated by the increase in pozzolanic activity of the fine fly ash and palm oil fuel ash and thus enabled the large replacement levels.

Strength and water permeability of concrete containing various types of fly ashes and filler material

Abstract In this study, the strength and water permeability of concretes containing various types of fly ashes and filler material were investigated. Five types of fly ashes with two levels of fineness and ground-river sand were used to partially replace Portland cement at the dosages of 20 and 40% by weight. Results indicated that pulverized coal combustion fly ash produced concrete with good strength and low permeability. Normal fluidized bed combustion fly ashes containing very irregular particles with pores produced concrete with low strength and relatively low permeability. Fly ash from fluidized bed combustion of coal with bio-mass materials and fly ash with high amount of CaO and SO3 produced poor concretes with low strength and high permeability. The increase in fly ash fineness helped improve both strength and permeability of concrete due to the increase in the reactivity of fly ash. Filler material could also be used to replace Portland cement at low replacement level of 20% with small effects on strength and water permeability.

Effect of W/B ratios on pozzolanic reaction of biomass ashes in Portland cement matrix

Abstract In this study, the effects of W/B ratios on pozzolanic reaction of by-product biomass ashes, namely rice husk–bark ash (RHBA) and palm oil fuel ash (POFA), were determined. These biomass ashes were ground to the same fineness as that of Type I Portland cement (OPC) and partially replaced OPC at replacement levels of 10–40% by weight of binder. Water to binder (W/B) ratios of 0.50, 0.575, and 0.65 were used. The compressive strengths of mortars were compared to those of mortars made with OPC partially replaced with ground river sand of similar particle size. The results demonstrate that at the same cement replacement levels, the degrees of pozzolanic reaction of RHBA and POFA increase with W/B ratio. In addition, ground river sand with the same particle size of OPC can be used as a non-reactive material to replace OPC for determining the compressive strength due to pozzolanic reaction of biomass ash.

Filler effect and pozzolanic reaction of ground palm oil fuel ash

This research examines the compressive strength of mortar and how the filler effect and pozzolanic reaction of ground palm oil fuel ash (POFA) contribute to this strength. POFA and river sand were ground to three different particle sizes and used to replace Type I Portland cement at 10–40% by weight of binder to cast the mortar. The compressive strengths of ground POFA and ground river sand mortars were determined at various ages between 7 and 90 days. The results showed that the compressive strength of mortar due to the filler effect of ground river sand was nearly constant during the 7–90 day period for a specified replacement rate of cement. However, the compressive strength of mortar due to the filler effect tended to increase slightly with increased cement replacement. The pozzolanic reaction of ground POFA increased with increasing particle fineness of ground POFA, replacement rate of cement, and age of the mortar. The compressive strength contribution from the pozzolanic reaction of ground POFA was much more pronounced than the contribution from the filler effect when the smallest sizes of both materials were considered.

Filler effect of fine particle sand on the compressive strength of mortar

The river sand, which is a non-pozzolanic material, was ground into 3 different particle sizes. Portland cement type I was replaced by the ground river sands at 10wt%–40wt% of binder to cast mortar. Compressive strengths of mortar were investigated and the filler effect of different fine particles of sand on the compressive strength of mortar was evaluated. The results show that the compressive strength of mortar contributed from the filler effect of smaller particles is higher than that of the coarser ones. The difference in compressive strength of mortar tends to be greater as the difference in ground river sand fineness increases. The results also suggest that ASTM C618 specification is not practically suitable for specifying pozzolan in concrete since the strength activity index of mortar containing ground river sand (high crystalline phase) with 33.8wt% of particles retained on a 45-μm sieve can pass the strength requirement.

Effect of Palm Oil Fuel Ash Fineness on Packing Effect and Pozzolanic Reaction of Blended Cement Paste

This paper presents the effect of particle size of palm oil ash on packing effect and pozzolanic reaction in cement paste. Ground palm oil fuel ash and ground river sand, having high crystalline and insoluble material of 2 different size with median particle size 15±1 and 2±1μm. Portland cement type I was replaced by palm oil fuel ash or ground river sand at 10, 20, 30 and 40 by weight of cementitious materials. The water to binder ratio (W/B) of 0.35 was used for all the blended cement paste mixes. Compressive strength of cement paste, percentage compressive strength due to hydration reaction, percentage compressive strength due to packing effect, percentage compressive strength due to pozzolanic reaction and fractured surface of cement paste were determined. The results showed that the packing effect of palm oil fuel ash cement paste increases with high fineness. Percentage pozzolanic reaction with median particle size smaller than cement was 12-23% at the age of 28 days. Palm oil fuel ash high fineness is good pozzolanic material and it can be used replace Portland cement Type I at the rate of 30% by weight of binder.

Strength and chloride penetration of Portland cement mortar containing palm oil fuel ash and ground river sand

This paper presents a study of the strength and chloride penetration of blended Portland cement mortar containing ground palm oil fuel ash (POA) and ground river sand (GS). Ordinary Portland cement (OPC) was partially replaced with POA and GS. Compressive strength, rapid chloride penetration test (RCPT) and chloride penetration depth of mortars were determined. The GS only asserted the packing effect and its incorporation reduced the strength and the resistance to chloride penetration of mortar. The POA asserted both packing and pozzolanic effects. The use of the blend of equal portion of POA and GS also produced high strength mortars, save cost and excellent resistance to chloride penetration owing to the synergic effect of the blend of POA and GS. For chloride depth, the mathematical model correlates well with the experimental results. The computer graphics of chloride depth of the ternary blended mortars are also constructed and can be used to aid the understanding and the proportioning of the blended system.

Grinding Properties of Abandoned Concrete

The grinding properties of abandoned concrete, which consists primarily of hardened cement, limestone aggregate and river sand, are studied. Theoretical models of grinding are used to explain the experimental observation. The results show that 1) The principle disintegration mechanism of hardened cement and river sand is volumetric grinding, although at later stages grinding of cement becomes difficult because of its flaked structure; 2) The limestone grinding process can be divided into two steps. First, volumetric grinding, with an obvious component of surface grinding, followed by primarily surface grinding as the micro-particle content increases; 3) Initially, the principle mechanism of grinding limestone and river sand is volumetric grinding, albeit less efficient grinding than if these components were ground separately, and; 4) After 10 to 20 min of grinding the grinding bottleneck phenomenon appears and after 20 min of grinding the content of micro-particles is large and surface grinding is the main mechanism while the particle size of the mixture is smaller than that of separately ground river sand and cement but bigger than that of separately ground limestone.

Micropropagation ofCereus peruvianus mill. (cactaceae) by areole activation

Currently,Cereus peruvianus plants can be rapidly clonedin vitro via adventitious organogenesis using callus cultures; however, somaclonal variation is a problem. A method is described herein using lateral bud explants to produce multiple shoots for clonal propagation. Apical and lateral explants were cultured on MS (Murashige and Skoog, 1962) media with factorial combinations of the auxins indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), and cytokinins 6-ben-zyladenine (BA) and N-(2-furanyl-methyl)-1-purine-6 amine (kinetin) at the concentrations 0.0, 0.01, 0.1, 1.0 mg“l−1. Positive results were obtained from the lateral explants in all conditions tested, but apical explants did not respond toin vitro multiplication ofC. peruvianus cactus at all growth regulator combinations tested. Formation of axillary shoots inC. peruvianus seems most frequent in medium containing BA at 1.0 mg·l−1 (4.44 μM) and IAA or NAA at 1.0 mg·l−1 (5.71 μM or 5.37 μM respectively), but the frequency of shoot formation in the BA or kinetin and NAA or IAA combinations indicated that any of the combinations tested can be used for multiplication ofC. peruvianus plants regenerated from callus tissue culture. Root formation occurred in all (100%) of the cactus shoots after 9 wk in the same culture medium. All the cacti that developed at the different auxin and cytokin combinations continued growth after transfer to a potting mix of red earth (Paleudult) and ground river sand (1∶1).