The influence of crystalline technology as concrete admixture on compressive strength and permeability

In regions prone to frequent rainfall or coastal exposure, concrete gradually becomes porous due to environmental influences. This study systematically examines the impact of different concrete formulations on compressive strength and permeability. It evaluates standard concrete, concrete with 1% and 2% crystalline admixtures, and concrete utilizing Portland cement type V. Compressive strength tests reveal that concrete with 1% and 2% crystalline admixtures, alongside Portland cement type V concrete, exhibit superior quality compared to standard concrete. Permeability assessments unveil intriguing trends: Portland cement type V concrete displays heightened permeability relative to standard concrete, while 1% and 2% crystalline admixture concretes exhibit significantly reduced permeability, surpassing both standard concrete and Portland cement type V concrete. The heightened concrete density associated with crystalline admixtures can be attributed to their dual influence on augmenting compressive strength and decreasing permeability. By reinforcing these mechanisms, crystalline admixtures effectively enhance concrete durability. This research contributes to the understanding of advanced construction materials and offers insights into sustainable infrastructure development possibilities. Subsequent sections delve into experimental intricacies, result explications, and wider implications of these findings, shaping the trajectory of future construction practices.


Introduction
Concrete, as a foundational material in construction, is inevitably susceptible to deleterious processes that compromise its durability.Among the prominent causative factors are external influences and the ambient conditions encompassing the concrete structure.Notably, regions characterized by recurrent precipitation or proximity to maritime zones exemplify settings where long-term concrete durability is jeopardized.
To address these concerns, the application of high-strength concrete has emerged as an astute choice, particularly in aggressive environments.This specialized concrete variant, in addition to its commendable mechanical robustness, boasts reduced permeability and porosity, thereby hindering the ingress of potentially corrosive agents to the inner concrete matrix.Consequently, this impedes their progression towards the core of the concrete structure.It is noteworthy, however, that despite the heightened adhesion between cement paste and aggregates that typifies high-quality concrete, its susceptibility to degradation within such contexts remains a salient apprehension.
In the pursuit of enhancing concrete performance, this study diverges from the conventional approach and instead focuses on the integration of crystalline additives during the concrete mixing phase.This strategic inclusion aims not at rectifying bleeding, as initially stated, but rather at investigating the broader ramifications of these additives on concrete's mechanical and permeability attributes.The crystalline additives, endowed with fine particulate morphology, confer the ability to modulate water loss, leading to controlled hydration dynamics.It is this nuanced interaction that forms the cornerstone of their potential influence on concrete performance.
The methodology employed involves the systematic introduction of these crystalline additives into the concrete mixtures, with varying concentrations to ascertain their impact.Subsequent to mixing, the specimens undergo a comprehensive battery of tests to discern alterations in compressive strength and permeability characteristics.This experimental rigour affords a robust basis for elucidating the efficacy of crystalline additives in influencing concrete properties.
The outcomes of this research not only augment the scholarly comprehension of concrete behavior but also bear tangible implications for the construction industry.By shedding light on the potential of crystalline additives to modulate concrete performance, particularly in terms of compressive strength and permeability, this study strives to contribute to the evolving paradigm of sustainable construction practices.

Crystalline admixture
This additive is a type of crystalline mixture containing portland cement, silica sand (reactive silica), and other chemical additives (reactive components).This chemical additive will react with Ca(OH) 2 to produce the formation of insoluble crystals throughout the pores and capillaries of the concrete which permanently seals the concrete and prevents the penetration of water and other liquids in all directions.[1] Based on the provisions of the admixture product, the recommended dosage is 0.8% -1.2% of the weight of the cement content.

Portland Cement Type V
Type V cement is used for concrete applications that require resistance to heavy sulfate levels (C3A content in cement is limited to a maximum of 5%).Cement hydration products with a C3A content of more than 5% will produce monosulfate hydrate which is unstable when exposed to a sulfate solution.[2] Tricalcium Aluminate (C3A) is a component that greatly determines the resistance of cement to sulfate compounds.The lower the C3A content in the cement, the more resistant the cement is to sulfate attack.

Slump Test
Slump value is a standard value to determine the workability of concrete.[3] The tools used for the slump test were an abram cone and a skewer with a diameter of 16 mm and a length of about 600 mm and having one or both ends in the shape of a hemispherical ball with a diameter of 16 mm.[4]

Compressive Strength Test
Compression strength test on concrete is when loading a concrete sample until it cracks and records the maximum load received by the concrete sample during loading.[5] f'c = Where: f'c = compressive strength on concrete sample (N/mm 2 atau MPa); P = load (N); A = area of concrete sample (mm 2 ).

Permeability Test
Water is applied under pressure to the hardened concrete surface.The specimen is then sectioned and the depth of penetration is measured.[6] The test shall be placed in the specimen in the apparatus and subjected to a water pressure of (500 ± 50) kPa for (72 ± 2) hours.During the test, make sure the surface is dry and not exposed to water.[6]

Concrete Durability
The durability of concrete is affected by the concrete's resistance to fluid penetration.This is mainly influenced by the cement water factor and the composition of the cementitious material used in the concrete.[7]

Concrete Mix Design
The preparation of the concrete mix design is an important phase in the concrete control process.The value of the concrete used will be inappropriate if the wrong combination is used.The first step in designing a concrete mix is determining the specifications that must be met.Mechanical efficiency, reliability, concrete properties and special criteria defined by project specifications.The solution to concrete's extraordinary characteristics is found in this process: it is plastic and malleable when freshly mixed, but solid and firm when it hardens.The correct selection and proportion of the constituent materials is the secret to producing strong and durable concrete.[8]

Slump Test
Based on the results of the concrete slump test as shown in Figure 1, the normal concrete slump value is 100 mm, the normal concrete slump value and crystalline admixture with a 1% content is 115 mm, the normal concrete slump value and crystalline admixture with a 2% content is 120 mm, and the slump value of normal concrete and type V cement is 130 mm.
The slump value of normal concrete and crystalline admixture added material with a content of 2% has a greater value than normal concrete and crystalline admixture with a content of 1% which indicates that the crystalline admixture added material is mixed in normal concrete, the slump value will get bigger.Both variants are only 5 mm difference.
The normal concrete slump value is the lowest slump value compared to other concrete sample variants.The slump value of type V concrete and cement has the largest slump value compared to other concrete test sample variants, which means that the workability of the concrete will be easier which refers to how easily the fresh concrete mix can be placed, consolidated and finished with minimal loss of homogeneity.

Compressive Strength Test
Based on the results of the concrete compressive strength test as shown in Figure 2, the compressive strength value of normal concrete and crystalline admixture with a content of 2% is the highest compared to other concrete sample variants where the compressive strength value is 43.54 MPa.The compressive strength value of normal concrete is the lowest where the compressive strength value is 41.01 MPa.
By using more crystalline admixture levels, the compressive strength of the concrete will be higher.This statement can be seen in normal concrete crystalline admixture with a content of 1% has a compressive strength value of 43.18 MPa and normal concrete and crystalline admixture with a content of 2% has a compressive strength value of 43.54 MPa.The difference in the compressive strength values of the two is not too far but higher than normal concrete and type V concrete and cement.
Type V concrete and cement has a higher compressive strength value than normal concrete but still lower than normal concrete and crystalline admixture where the compressive strength value of type V concrete and cement is 42.76 MPa.By changing the type of cement or adding crystalline admixture crystalline admixture, the compressive strength of the concrete will be even higher.Compressive Strength Test

Permeability Test
Based on the results of the concrete permeability test as shown in Figure 3, the permeability value data of concrete which are colored red and printed in italics are anomalous data (unexpected distorted data arising from certain processes) caused by the presence of a large enough air shaft in the concrete test object so that the data does not become valid data and is not included in the calculation of the average concrete permeability value.The permeability value of normal concrete and crystalline admixture with a content of 2% is the lowest compared to other concrete sample variants where the permeability value is 15 mm.The permeability value of type V concrete and cement is the highest where the permeability value is 48.33 mm.
The permeability value of normal concrete and crystalline admixture with a content of 1% has a permeability value of 20 mm and normal concrete and crystalline admixture with a content of 2% has a permeability value of 15 mm.The difference in the permeability values of the two is not too far but lower than normal concrete and type V concrete and cement.
Normal concrete has a lower permeability value than type V concrete and cement but both are still higher than normal concrete and crystalline admixture where the normal concrete permeability value is 43.50 mm.

Conclusion
1.In terms of compressive strength test.Concrete and crystalline admixture with a content of 1%, a content of 2%, and concrete with portland cement type V are proven to have much better quality compared to normal concrete; 2. In terms of permeability test.The use of type V cement in concrete proved to be less optimal than normal concrete, so that type V cement needs to be reviewed.Concrete and crystalline admixture with a content of 1% and 2% are proven to have lower permeability values than normal concrete and concrete with portland cement type V; 3. The addition of crystalline admixture additives produces a higher concrete density value than normal concrete which can help increase compression strength and reduce the permeability of concrete structures.Therefore, the addition of crystalline admixture is proven to be used as an alternative to replace the use of type V cement.

4 Figure 1
Figure 1 Diagram of Concrete Slump Test Results

Figure 2
Figure 2 Diagram of Concrete Compressive Strength Test Results